Manual:Technical Manual

Multi Session Gaming

Mudlet lets you play several simultaneous MUD sessions. However, currently we have the restriction that you cannot use the same profile twice. Consequently, if you want to play three characters on the same MUD at the same time, you need to make 3 profiles with 3 different names e.g. ernie@avalon.de, bert@avalon.de etc.

Split Screen

Mudlet has a split screen. If you scroll up in the MUD text screen (or any other mini console window), the screen will split in two parts. The lower part will follow the MUD output while the upper part will stay focused on your scrolling. This way you can read easier through old passages without missing what is going on at the moment.

Split screen can be activated via the scroll bar, page up / page down keys or the mouse wheel. Scrolling back to the end will close the split screen automatically. A click on the middle mouse button will close the split screen immediately as well as pressing control+return on the keyboard (command+return for mac). The size of the 2 parts of the split screen can be modified by dragging the separator bar in the middle with the mouse. Split screen usage is necessary when selecting text in order to copy it to trigger editor e.g. when making triggers. If you don’t use split screen when selecting text, new arriving text will upset your selection.

Command Line Auto-Completion, Tab-Completion and Command History

Mudlets command line is especially designed for MUD and MUSH playing. It aims at reducing the amount of typing by using autocompletion and tab completion schemes that are optimized for typical MUD playing situations. The command line offers tab completion (TAB key with or without shift) and autocompletion (cursor up and cursor down keys).

Tab completion searches the last 100 lines in the MUD output buffer for words matching the word that you are currently typing. This is useful if you have to type complicated long names. You only have to type the first letters and then press the tab key until the proposal is what you want.

Autocompletion tries to match your current typing with your command history. Example: If you typed the same command a while ago, you only have to start typing the first couple of letters and then press the cursor up key until the proposal matches the command that you want to use.

Command history - if you haven’t started to type anything yet, you can browse through your command history with the cursor up and cursor down keys. However, if you have started typing pressing cursor up will result in a shot at autocompletion.

Escape key - to get out of autocompletion you can press the ESC key any time. After pressing ESC the entire text gets selected and you can overwrite it or get back into command history mode.

Using Variables in Mudlet

One of the major design goals in Mudlet was to integrate scripts and variables into triggers/aliases/buttons etc. as seamlessly as possible. The usage of variables in Mudlet is distinctly different from the other major clients, as native Lua scripting has been integrated into Mudlet from the ground up. As scripts are so closely intertwined with the core of Mudlet, variables do not need any special treatment as in other clients i.e. there is no need for code such as:

totalKills = getVariable("killedMonsters") + getVariable("killedVillains")
echo( "kills=" .. totalKills )

In Mudlet, the above code translates into:

totalKills = killedMonsters + killedVillains
echo( "kills=" .. totalKills )

If you define a variable in any given script in Mudlet, be it a trigger, a button, an alias key, an event handler, a free function, etc. It can be used from within any context without any special getVariable() type of function or any special variable symbols, such as @myVar etc.. In Mudlet all variables are native Lua variables. Each session (= profile/connection tab) runs in its own dedicated Lua interpreter. Consequently, all scripts of a profile are compiled into the same Lua interpreter and thus their code runs in the same variable space. All scripts from another simultaneously opened profile will not interfere because each profile uses its own Lua interpreter. Note Everything shares the same variables & functions.

To give you an example: Let’s make a little trigger that counts how many monsters you have killed. Each time you have made a new kill, the trigger matches on the kill message and runs a little script that increases the amount of kills by one each time the trigger fires - in other words, each time you kill a monster and the kill message is sent from the MUD. For the kill counter we declare a variable and call it myKills. This variable is going to hold the number of kills we’ve made so far. The script will look like this:

myKills = myKills + 1

Then we add a little alias, a button or a keybindings that executes another little script that prints your current kill statistics on the screen. The attached script would look like this:

echo( "I have killed " .. myKills .. " monsters today." )

Lua variables can be either a string of letters (aka string) or a number, among a few others. They are whatever there were initially created with or what data type they can be converted to.

a = "Jim"
b = "Tom"
c = 350
d = 1

--Then you can write:

e = c + d -- and e will equal 351
e = a .. b -- and e will equal "JimTom" 
e = a .. c -- and e will equal "Jim350"

Note: You can't use a + b to concatenate string values. For this you must use the double-dot: ..

String Interpolation - the f function

However, starting with Mudlet 4.11.0 we have included the f function to perform string interpolation. This is a very fancy way of saying "replacing code in strings with their value". When you run a string through the f function then it replaces anything inside a pair of {} with the value of the variable or outcome of the expression. To expand upon the example above:

a = "Jim"
b = "Tom"
c = 350
d = 1

function simple_addition(a,b)
  return a+b
end

--Then you can write:

e = c + d -- and e will equal 351 (no change here)
e = f"{c + d}" -- end e will equal "351". This is a string, not a number, if you need to do math with e then do it like above.
e = f"{simple_addition(c,d)}" -- same as above, but shows using the function we've defined.
e = f("{a}{b}") -- and e will equal "JimTom" 
e = f"{a}{c}" -- and e will equal "Jim350"

A shrewd observer might notice that I have written the above uses of f without the usual parentheses. In Lua you can omit the () when you are only passing a single string argument to the function. It is usually considered best practice to include the () but in the case of f for interpolation I find it reads a bit better without them. As shown in the example above it works with or without them in place.

For a more 'real world' example and comparison of concatenation, f, and string.format consider the following:

-- For the following, we assume the following variables exist:
-- target which holds the target's name
-- target_health_color which is a cecho color determined elsewhere
-- target_health which is the actual health the target has.

-- this function uses the concatenation operator .. to glue strings together for display
function displayTarget()
  local msg = "\n<green>Target:<r> " .. target .. " <green>Health:<r> " .. target_health_color .. target_health
  cecho(msg)
end

-- this function does the same thing, but uses f
function displayTarget()
  local msg = f"\n<green>Target:<r> {target} <green>Health:<r> {target_health_color}{target_health}"
  cecho(msg)
end

Tables as Lists

There is another form of variables in Lua called tables which can be used for lists, arrays or dictionaries. This is explained later. For an in-depth coverage of variables in Lua take a look at a Lua tutorial e. g. this one on numbers http://Lua-users.org/wiki/NumbersTutorial and this one on strings http://Lua-users.org/wiki/StringsTutorial or this one on Lua tables http://Lua-users.org/wiki/TablesTutorial

Let’s get back to our example. The trigger script expects myKills to be a number so you have to initialze the variable myKills to 0 before running the script for the first time. The best place to initialize variables is in script script outside of a function definition as this code is executed when the session is loaded or if you compile the script again after you have edited it. To do this click on the "Scripts" icon and select the standard script "My Global Variable Definitions". If you are using an older version of Mudlet or a profile that doesn’t have this script item, simply click on the "Add" icon and make your own script. You can call it whatever you want to. Add following code to initialize your new variable myKills to a number and set its value to 0:

myKills = 0

Whenever you edit this script, it will be recompiled and the code will be run as it is not part of a function definition. This is the major difference between trigger-scripts, alias-scripts etc. and script-scripts. Script-scripts can contain an unlimited amount of function definitions and also free code i. e. code outside of a function definition - code that is not enclosed by function xyz() …. end. On saving the script the script gets compiled and the free code is run instantly. All other item scripts, i. e. trigger-scripts etc., secretly define a function name for the script and thus the script is not free code, but function code. When a trigger fires Mudlet calls this invisible function name to run the script e.g. trigger738(), button82(), alias8(). This means that if you define variables inside a trigger script the variable will not be defined before the trigger runs for the first time. However, if you define this variable as free code in a script-script the definition becomes available immediately on script save. Now, whenever you add new variables to your variable definition script, the script gets run and your old variables will be reinitialized and reset to 0. This will be no big problem in most cases as you won’t work on your systems while really playing in most cases. To solve this problem you have two options:

First option: Add a script group (a folder) and add a new script item for each variable you define. This way, editing a variable definition will only reset the edited variable and none of the others that are defined in different scripts. This has the added advantage that you have a nice graphical overview of your defined variables. Note Organize your variables

Second option (more advanced): Change the variable initialization to only initialize the variable if it hasn’t been initialized before, thus keeping the values of previously defined variables. The following code initializes the variable myKills (to the number 0) but only if it hasn't been initialized before. This would look like this:

if myKills == nil then    
    myKills = 0
end

In Lua all undefined variables are initialized to the value nil. The value nil is not the same thing as the number 0 or the empty string "". What it means is that a variable that has the value nil has not been declared yet and does not exist. If a variable does not exist, it cannot be used as its value is undefined at this point. Consequently, increasing the value of nil by one is impossible as the variable doesn’t exist yet and will lead to a Lua error. The above script simply checks if the variable myKills has been defined yet and if it hasn’t, it will declare the variable and set its value to 0.

Having variables that hold a single value is the most important usage of variables, but very often you’ll like to define variables that hold a list of values e. g. a list of your enemies, a list the items you are currently carrying etc.. To define a variable to be a list you need to declare it to be a Lua table. Let’s declare the variable myEnemies as a list containing the names of your enemies:

myEnemies = {}

You can now add new enemies to this list by calling the Lua function table.insert( listName, item ). For example:

table.insert( myEnemies, "Tom" )
table.insert( myEnemies, "Jim" )

To print the contents of your enemy list on the screen, you can run this script:

display( myEnemies )

Now, let’s make a little alias that adds a new name to your enemy list when you type "add enemy" followed by the name of the enemy (e.g., "add enemy Peter"). Open the alias editor by clicking on the "Aliases" icon. Click on the "Add Item" icon to add a new alias. Choose any name you like for your alias (e.g., "Add Enemy Alias"), and then define the following pattern for the alias: ^add enemy (.*). Next, add the following little script in the script input field below your alias:

table.insert( myEnemies, matches[2] )
echo( f"Added a new enemy:{ matches[2] }\n" )

Save the alias by clicking on "Save Item" and try it out by entering into the Mudlet's command input line. Aliases are explained in further detail below.

Another way to declare a list is to define its values directly. For example,

myEnemies = { "Peter", "Jim", "Carl", "John" }

To remove an item from the list, you can use the function table.remove( listName, item index ).

Saving variables

You might notice that Mudlet doesn't save your variables between profiles restarts. The reasons for this are technical, but all it means is that you have flexibility in how to deal with them. There are several ways, so the most common and easiest ones will be explained here.

Tick the box in the variables view

Head to the variables view in the Mudlet editor and tick the box besides a variable - Mudlet will remember it between restarts now!

Saving by coding them in a script

The title sounds a bit complicated, but that's pretty much what you do. Go to Scripts, click `Add Item`, and create your variables like so:

myname = "Bob"
mypack = "pack1234"
rapierID = 67687

Now, since scripts are run when the profile is started, these variables will be created and assigned to those values. This was simple to do, but it has one problem - if you want to change the value of the variables to be saved, you have to edit the script by hand each time; and if you change the value of variables while playing via scripting, the new values won't be recorded.

Saving via table.save & table.load

Next, enter a more proper solution. This'll actually save the variables to a file and load them from it - so if you change the variable values, the current ones will be saved, and will be loaded next time properly. This method works with a table containing your variables though, not individual variables themselves - see Lua tables tutorial on how to create and use those.

table.save(where to save, what table to save) takes the location and name of a file to save variables to, and a table containing your variables to save. Location can be anywhere on your computer, but a good default place is your profile folder, whose location can be obtained with getMudletHomeDir().

mychar = {
  name = "Bob",
  age = 26,
  sex = "male"
}

local location = getMudletHomeDir() .. "/mychar.lua"
table.save(location, mychar)
-- sample echo to show where the file went:
echo(f"Variables saved in: '{location}'")

table.load(where to load from, what table to use) is similar - it takes the location and name of the file to load, and a table name to use for the loaded variables.

mychar = mychar or {}
table.load(getMudletHomeDir() .. "/mychar.lua", mychar)
display(mychar)
echo(f"My name is: {tostring(mychar.name)}")

Now that you have a way to save and load your tables, you can create triggers to load and save your variables at appropriate times, and you'll be set.

React on input - Mudlets Alias Engine

Note: A screencast is available on getting started with aliases - watch it!

Mudlet has a feature called "aliases" that allows you to set up certain phrases or commands that will automatically trigger certain actions or responses. These actions are defined using a specific type of language called "Perl regex expressions." Aliases only work on the input that the user types into the command line, while a separate feature called "triggers" works on the output that the game sends back. When you type a command and press enter, it is sent to the alias feature to see if it matches any of the phrases or commands that have been set up. If it does match, the alias will take over and either send a different command to the game or run a script (a set of instructions) that you have defined. This system is powerful because it gives you control over what happens when a certain phrase or command is entered. You can even change the user's input as it is being processed, allowing you to manipulate the command before it is sent to the game.

The example in the diagram above shows 2 matching aliases, but only one of them sends commands to the game - and only if the player is healthy enough to attack the opponent. The other alias that matched the user input (enemy) choses a fitting opponent and sets the variable enemy accordingly, otherwise it issues a warning that attacking one of the available enemies would be too dangerous.

For an alias to match the command text the same rules as explained above in the trigger section apply. However, to simplify matters there is only one alias type. As alias are not performance critical we could reduce the amount of trigger types to just Perl regex as this type can do it all and performance is no issue with alias as the amount of data is much less. Even if you type like a madman you’ll never get close to sending the same amount of text to the game than the amount of text the game sends back to you.

What does it mean that a regex is true or "matched"? A trigger or an alias fires - or executes its commands/script - when the text matches the pattern of the trigger or alias. In most cases this means that the text contains the trigger/alias pattern. If the regex pattern is reen then a text "The green house" will match because "reen" is contained in the text. More complex regex patterns can also hold information on where in the text a certain pattern must occur in order to match. ^tj only matches when the letters "tj" occur at the beginning of the text. Consequently, a text like "go tj" would not match. Regex patterns can also capture data like numbers, sequences of letters, words etc. at certain positions in the text. This is very useful for game related scripting and this is why it is explained below.

Let’s get back to alias. We start with a simple example.

We want Mudlet to send "put weapon in bag" whenever we type "pwb". Consequently, the pattern is pwb and as the task is so simple it’s enough to enter "put weapon in bag" in the send field. Then we click on save to save the changes and activate the alias by clicking on the padlock icon. Then we leave the trigger editor and test our new alias. After typing "pwb" and pressing return Mudlet will send the command "put weapon in bag" to the game.

Let’s move on to a more complicated example that is needed very often.

We want our script to automatically put the weapon in the correct bag as we have many bags and many weapons. The pattern stays the same. ^pwb The ^ at the beginning of the line means that the command starts with pwd and no other letter in front of this. If we define our pattern more clearly, the pattern will match less often. Without the ^ the alias will match and the alias script will always be run whenever there is the sequence of letters "pwb" in your commands. This may not always be what you want. This is why it’s usually a good idea to make the pattern definition as exact as needed by being less general. The more general the pattern, the more often it will match.

Back to our task: The pattern is ^pwb. Let’s assume that we have defined 2 variables in some other script. The variable "weapon" is the weapon we use and the variable "bag" is the name of the bag. NOTE: In Mudlet global variables can be accessed anywhere from within Mudlet scripts - no matter if they have been defined in a trigger script, in an alias script or in a key or button script. As soon as it’s been defined it somewhere it is usable. To make sure that a variable is local only, i. e. cannot be referenced from other scripts, you have to use the keyword local in front of your variable definition. Back to our alias: Pattern is: ^pwb

Script is:

send(f"put {weapon} in {bag}")

Depending on the values of our variables weapon and bag the command "pwb" will be substituted with an appropriate command. To set your weapon and bag variables we use 2 more aliases: Alias to set the weapon: uw (\w)+

Script:

weapon = matches[2]
send( "wield " .. weapon )

To set our bag variable: Pattern:^set bag (.*)

bag = matches[2]

Now let’s go back to our initial problem. We want an alias to put our current weapon into our current bag. But what happens if we are in the middle of a fight and absolutely need to sip a healing potions because we are close to death and cannot take the risk that the bag may be too full to take the weapon? We want to upgrade out little alias to take into account that the bag may be full and chose an empty bag instead. To do this we set up a trigger that detects messages that indicate that the attempt to put the weapon in the bag failed. In this trigger we execute this little bag-is-full-detection-trigger Trigger Pattern: (type substring) Your bag is full.

Script:

bagIsFull = true;

This detection trigger will set the variable bagIsFull to true as soon as it sees the message "Your bag is full.". Then you know that you have to use your spare bag to take the weapon.

Now we have the tools to write an improved version of our little alias script:

if bagIsFull then
    send(f"put {weapon} in {spareBag}")
else
    send(f"put {weapon} in {bag}")
end

The next example is one of the most common aliases a tell alias: Pattern:^tj (.*)

Script:

send("tell Jane " .. matches[2])

Sadly, Jane is your fiancée and the one thing she is a vegetarian and absolutely hates all words that relate to meat. Luckily, you know enough about aliases by now to make her believe that you’d never ever even think about meat. So you head to your global function script (any script item will do as long as you define your variables outside of your function definitions. See the scripts chapter below for more information. In your script "my global functions" you add a Lua table containing a list of all of all words that a vegetarian might hate. For example:

happyJaneTable = {"meat", "burger", "steak", "hamburger", "chickenburger"}

Now you can upgrade your tell-jane script to automatically search our tell for all words that Jane might not like. In case such a word is found we substitute the entire tell with "How is the weather?".

for key, value in ipairs(happyJaneTable) do       -- looking at each element of the list
    badWord = happyJaneTable[key]                 -- check out the Lua table chapter below for more info
    begin, end = string.find(command, badWord)    -- begin holds the start position of the word, end* the end-position
    if begin ~= nil then                          -- we have found a bad word
        send("tell Jane How is the weather?")
        return
    end
end

Alias Examples

Alias:

^cc( .+)?

Script:

local target = matches[2] or ""
send("c cure critical" .. target)

Default keybindings in the main window

Keypress	Action
Left Arrow	Moves the cursor one character to the left.
Shift+Left Arrow	Moves and selects text one character to the left.
Right Arrow	Moves the cursor one character to the right.
Shift+Right Arrow	Moves and selects text one character to the right.
Home	Moves the cursor to the beginning of the line.
End	Moves the cursor to the end of the line.
Backspace	Deletes the character to the left of the cursor.
Ctrl+Backspace	Deletes the word to the left of the cursor.
Delete	Deletes the character to the right of the cursor.
Ctrl+Delete	Deletes the word to the right of the cursor.
Ctrl+A	Select all.
Ctrl+C	Copies the selected text to the clipboard.
Ctrl+Insert	Copies the selected text to the clipboard.
Ctrl+K	Deletes to the end of the line.
Ctrl+V	Pastes the clipboard text into line edit.
Shift+Insert	Pastes the clipboard text into line edit.
Ctrl+X	Deletes the selected text and copies it to the clipboard.
Shift+Delete	Deletes the selected text and copies it to the clipboard.
Ctrl+Z	Undoes the last operation.
Ctrl+Y	Redoes the last undone operation.
Ctrl+<Click>	Select the whole line.
Ctrl+Enter	Close split screen (scroll all the way to the bottom).
Ctrl+F	Search for text in the main output window.

Considerations

• Mudlet 4.17.2 currently does not support named capture groups for aliases.
  • You will need to use matches[1],matches[2] etc. instead.

• You can use modifiers for these regexes. Declare these at the start, in the form (?modifiers)
  • For example, to match the command test, ignoring case, you would need to declare the regex as being case-insensitive, like so: (?i)^test$

Trigger Engine

Unlike alias that define patterns that match on user input, triggers define patterns that match on game output. In other words, triggers react to text that has been sent by the game, whereas alias react to user commands that have been typed into the command line.

Simple Trigger Matching

Note: QUICKSTART: Here is a simple video tutorial on how to make basic triggers in Mudlet.

Steps To Create A Trigger

1. Click on the "Add" button to create a new trigger.
2. Put the text pattern that you’d like to trigger on into the trigger conditions table on the right side of the screen above the script editor.
3. Choose the correct pattern type of your trigger pattern in the drop down list on the right side of the trigger pattern i.e. in the second column of the trigger pattern table. If you define multiple patterns in the same trigger, your trigger will run whenever any one of these patterns matches unless you chose the AND-trigger option, in which case the trigger will only fire if all patterns match within a specified amount of lines from the game. For more advanced information on AND and OR trigger see the corresponding AND/OR trigger section below.
4. Define what happens when the trigger matches. Usually, this will be done by a Lua script in the Lua editor below the table with the pattern list. In the beginning, you can simply choose the "highlight trigger" option to make your trigger highlight the text that it has triggered on or send a clear text command to the game whenever the trigger fires until you have learned enough Lua to more meaningful scripts. Clear text command can be defined in the "send plain text" input box next to the trigger name above the pattern table.
5. Save the new trigger and then activate it with the padlock icon button. By default, new triggers are deactivated and thus will do nothing unless you explicitly activate them. Activated triggers show a green tick in the little blue box on the left side of the trigger name in the trigger tree on the left side of the script editor dialog.

There are three ways to save your changes; click on the save icon, adding another new trigger, clicking on another trigger item. Triggers that have not been saved yet cannot be activated.

Note: If you see a bug icon instead of an activation box, there is some error that prevents activation of your trigger. Check the error message above the pattern table.

Example: You want to trigger on the word "pond" in a line such as: "The frog swims in the pond. Plop." All you need to do is add "pond" as a pattern and choose "substring" as a pattern type. Then enter the command you like to send to the game if the trigger matches. For example enter "drink water" into the "send plain text" input box and activate your new trigger. Your new trigger will send the command "drink water" to the game any time it sees the word "pond" somewhere in the game output.

Simple Highlighter Triggers

Note: Beginners should use Mudlets automated highlight triggers in the beginning to get the hang of the different trigger and pattern types quicker.

1. Create a new trigger and add a pattern as detailed above.
2. Click on the "highlight trigger" option and pick a foreground and a background color. When the trigger matches it automatically highlights its pattern.
3. Save.

This is one of the most used form of triggers in mudding. It is a quick way of highlighting words that are important to you at the moment. This helps you spot things at a single glance instead of reading the entire text. You don’t have to know anything about scripting, regular expressions etc. to use highlight triggers. Just type in the word you like to be highlighted, select appropriate colors, save the new trigger and activate it.

More advanced users will often want to do custom highlighting from within scripts. This is how it works: If you want to highlight the word "pond" in the above example you have to add the following little Lua script to the script editor on the lower right side of the Script Editor window:

selectString( "pond", 1 )
fg( "red" )
bg( "blue" )
resetFormat()

Testing Triggers

You can test your triggers with the `echo alias from the command line. This requires the echo package, which is installed by default on a new profile.

`echo A test line.

`echo One line.$Next line.$Third line.

Or from your Lua code using feedTriggers

feedTriggers([[
You are carrying:
  a credstick                                       a pair of steel toed boots (worn)
  a Soko Sukeban (worn)                             a medikit
  a cherry moon katana                              a GPS device
  a NV contacts                                     a Tsunami MkII
  a MeshGirl Helm                                   an Alto 500 CellPhone
  a Kantan Sukeban (worn)                         
Your load barely slows you down.
]])

Alternatively, you can also record a replay and play it - triggers will be matched on it.

Pattern Matching Types

Substring

This trigger type will match any text on a single line. Useful for matching strings of text which don't change at all.

Examples:

---

Pattern:	pond
String:	The frog swims in the pond.
Outcome:	match (pond matches the word pond)

---

Pattern:	pond
String:	The frog swims in the swamp.
Outcome:	no match (pond does not match swamp)

---

Perl Regex

This trigger type will match text using Regular Expressions (Regex). Regex in Perl is a special text string for describing a search pattern within a given text. For example \w+ is used to match a single word, or \d is used to match a single digit.

Pattern matching also allows the match to be saved in the matches table variable if enclosed in parentheses. matches[1] contains the entire line of the trigger whereas matches[2] contains the first regex pattern (in our examples pond or swamp).

Examples:

---

Pattern:	The frog swims in the (\w+).
String:	The frog swims in the pond.
Outcome:	match (\w+ matches pond, and is also saved to matches[2] variable)

---

Pattern:	The frog swims in the (\w+).
String:	The frog swims in the swamp.
Outcome:	match (\w+ matches swamp)

---

Pattern:	The frog swims in the (\w+).
String:	The fish swims in the pond.
Outcome:	no match (fish should be changed to a regex pattern \w+)

---

Note: regex101.com is highly recommended to testing out your regular expressions. It includes a pattern tester, cheat sheet and explanations about the matches.

Start of Line

This is a combined variation of substring matching and regex matching. This type will match any line with text at the start of the string only.

Examples:

---

Pattern:	The frog
String:	The frog swims in the pond.
Outcome:	match (The frog is at the start of the string)

---

Pattern:	frog swims
String:	The frog swims in the swamp.
Outcome:	no match (frog swims is not at the start of the string)

---

Note: This is exactly the same as using a Perl regex pattern with the ^ anchor (start of a line).

Exact Match

The string must match exactly the pattern. On a whole line, this is the same as using a perl regex pattern with the ^ and $ (start and end of line) anchors.

Examples:

---

Pattern:	The frog swims in the pond.
String:	The frog swims in the pond.
Outcome:	match (the entire line matches)

---

Pattern:	The frog swims in the pond.
String:	The frog swims in the pond. The bird flies in the sky.
Outcome:	no match (The entire line does not match as the bird information has been added. This would match a start of line pattern though)

---

Lua Function

The purpose of Lua function triggers is to be able to run Lua scripts as trigger conditions. This trigger types takes an actual Lua function as the pattern. This function must return true or false to evaluate correctly, but will only match when returned true.

For example, let's say we wish to enable our entire offensive combat triggers when we commence combat, but otherwise be disabled when we are not in combat. One would create a trigger chain that contains all the offensive triggers. The chain head (the root trigger of the chain) simply contains this Lua function condition as its only trigger condition: return inCombat

Now, whenever you enter combat you set the variable "inCombat" to true and thus automatically enable you entire combat triggers that are otherwise disabled.

Examples of patterns:

• if myVar > 20 then return true else return false end
• if myFunc() < myVar then return true else return false end
• return myFunc() if myFunc returns a boolean value

Another example:

Create a new trigger with the pattern checkHealth(). Define a new Lua function checkHealth(). Open the script editor, add a new script "health monitor" and add this code to the new script.

function checkHealth()
    if health <= 100 then  -- health is a variable we capture from e.g. the prompt or GMCP
        echo( "WARNING: Low health! I have to run away!\n" )
        send( "flee" )     -- we send a command to run away to the game
        return true
    else
        return false
    end
end

Lua Syntax Primer: Expressions

Note: Mudlet used to only allow the boolean true value as the return value to consider the pattern to have been a match. It has since been improved to allow any value Lua would consider true - but if you see any Lua Function Conditions (LFC) making use of and true or false at the end, that'd be why.

if A == B then (...)   ----> if A equals B
if A ~= B then (...)   ----> if A *NOT* equals B
if A <= B then (...)   ----> if A is smaller or equal to B
if A >= B then (...)   ----> if A is greater or equal to B
if A < B then (...)    ----> if A is smaller than B
if A > B then (...)    ----> if A is greater than B

The operators and and or behave differently in Lua than in most other programming languages as they are not guaranteed to return a boolean value.[1]

Lua Function Conditions (LFC) effectively means that you run the Lua code they represent on every single line that is received from the game, unless the LFCs are part of a multi-condition trigger, in which case the LFCs would only be run when they would be the current test-condition of their respective trigger state. LFCs are implemented in such a way that the trigger engine only calls the compiled byte code, but running as few scripts as possible is always the best idea. LFCs are nice and handy, and for most people the performance aspect will not be relevant at all.

Line Spacer

To make the engine skip lines in a multiline / AND trigger, use the line spacer pattern: select 'line spacer' as the type and put in a number on the left to make it go to the next X lines, for example 1 will make it go to the next line. See the multline section below for further explanation.

Color Trigger

This type of trigger matches the color of the text, as opposed to the actual text incoming. Both foreground and background matching is available and you will be prompted to select the required colors.

Examples:

---

Pattern:	Foreground color [ANSI 12], Background color [ANSI 15] (blue foreground on a white background)
String:	The bird flies in the sky.
Outcome:	match (the COLOR matches)

---

Prompt

This type of trigger will only work with servers that have implemented the telnet suboption GO AHEAD. If you server does not implement GA this will be shown in the bottom right corner of Mudlet with the characters No GA.

This option has one function, to match your prompt and will fire when it does.

Multi-Line Triggers and Multi-Condition Triggers

Multi Condition Triggers are the most advanced feature of Mudlets trigger engine. Like trigger chains or filter chains they are a form of AND-Triggers. All conditions in the list must have matched within the specified margin of lines (delta), in order to trigger the script. Normal triggers fire and run the script as soon as one of the conditions in the regex list is met i.e. if one of the regex/string matches match - or the Lua function condition returns true, the trigger script is run. In multiline triggers, however, each single regex/string/Lua function condition in the list has to have matched within the specified margin of lines at least once to trigger the script. The sequence of the conditions is binding. This means that if the 10th regex on the regex list would be matched on the eleventh line after the match of the first line happened, the trigger will NOT run unless the margin of lines is set to 11. If condition #3 is true but currently #2 is waiting to be true, condition #3 is ignored and must be true again after condition #2 has been true. Conditions can also be Lua Functions or plain Lua code that returns a boolean truth value. You can mix all types of conditions to build complex multi-condition triggers that only fire if all conditions are met. This is a very powerful feature as it reduces the amount of scripting to a minimum or even takes away with the need to script formerly complex processes completely. Multicondition triggers are multi-line triggers, i. e. the conditions can all be met in a single line or many lines after the first condition has been fulfilled. This effectively reduces the amount of complexity as you have all the important conditions placed into a single trigger and all the tedious bookkeeping, variable and condition state accounting is being done by Mudlets trigger engine. The result of this is that the amount of manual condition checking via many different trigger scripts and legions of if condition1 == true then check condition2 can be forgotten about. All you have to do is to define the conditions and the final action that is taken if the trigger fires.

Note: to retrieve wildcards in multi-line or multi-condition triggers, use the multimatches[line][match] table instead of matches[].

Note: This diagram shows what steps are involved in the process of problem solving with Mudlets trigger engine. The main question is: How do we arrive at a solution to our problem, and how can we simplify the problem as much as possible?

Example: Let’s go back to our pond & frog example. We have explained the difference between AND-triggers and OR-triggers. If you have a room description consisting of 3 lines:

1. You see a pond
2. You see a frog.
3. The frog sits on a stone.

Every single one of these 3 lines will be fed into the trigger engine one after another. If we define an OR-trigger with a condition list consisting of 3 condition patterns:

condition #1 pattern = pond

condition #2 pattern = frog

condition #3 pattern = stone

Whether or not a condition is found to be true also depends on another property, namely the type of the condition. The condition type can be among others:

1. substring matching → the condition is true if the condition pattern is a substring of the output line from the game. In other words: If the pattern "pond" is contained in any line of output, the condition is true.
2. begin of line matching → the condition is only true if the condition pattern can be found at the beginning of a line from the game.
3. Perl regular expression → the condition is true if the Perl regex pattern is matched. You’ll find more information on Perl regex below.
4. Lua code that returns a truth value e.g. a call to a function check() that return either true or false depending on the condition

In our example we chose condition type "substring" for all three conditions. Consequently, the trigger will fire the command or script 3 times i. e. the trigger will do on each line it is matched against because in every line at least one condition evaluates to true because the pattern is a substring of the line.

in line #1 we get: pond = true.

in line #2 we get frog = true and

in line #3 two conditions are true i.e. frog=true and stone = true

Because an OR-trigger fires on the first condition that is true and ignores the rest the trigger will only execute 3 times on these 3 lines although 4 conditions are true.

Note: CAUTION: The multi line condition switch must be turned off to get an OR-trigger! If the multi-line condition switch is turned on the trigger becomes an AND trigger which means that the trigger only fires if all conditions are true and fulfilled in the correct sequence. With OR-triggers the sequence is irrelevant.

To complicate matters, however, you don’t want your trigger to fire 3 commands, because you want to use this room description as a whole to fire your trigger e. g. this pond is the only kind of ponds in the entire world that doesn’t have poisoned water. So you want to make sure that you only drink water from a pond of this kind and from no other pond. Your solution is to use Multi Condition Triggers (MCT). If you check the MCT checkbox this trigger will fire only once from now on - and only if all conditions are met i e. when you can guarantee that you only drink water from a good pond because your drinking trigger is matching on the entire room description despite that this room description my be spread over a number of lines. (NOTE: If you have word wrap turned off in your game chances are that the entire room description will be contained in a single line, but we are trying to keep the examples as easy as possible.)

Sadly, there are many unfriendly people in this world and somebody goes around and poisons your good ponds. Consequently, you would want to examine the frog and find out if it is poisoned before drinking water from the pond. This is difficult because the villain is a mean magician who used illusion spells to make everything look like the good pond. To solve the problem you can now resort to Lua function conditions in the trigger condition list that perform certain check ups to put the current room description into a wider context e. g. check if you have been here before etc. This adds yet another level of complexity to your problem but this is a very powerful means to use the full potential of Mudlets MCTs.

You can combine all forms of conditions with trigger chains, filters and Lua functions. Mudlet gives you relatively easy to use tools that require no programming background. However, these tools can evolve into complex powerful problem solving mechanisms if they are combined with each other thus enabling non-programmer users to solve problems that would need a profound programming background in other gameclients. However, unlocking the full potential of Mudlet requires you do learn some Lua basics. In this manual we’ll try to be as easy on you as we can in this respect, but it’s highly recommended that you dig deeper into Lua after a while. It’s one of the easiest fully fledged scripting languages available, easy to learn and the fastest of them all, and this is why it has been chosen by us. You don’t need to become a programmer to be able to use Mudlet effectively. All you have to know is how to work with variables and how to do if conditions and maybe a few loops. But knowing more won’t harm you and it will make your systems more effective.

"multiline / AND" and "OR" Condition Triggers

Multiline, or AND triggers execute their respective command or script only if all conditions in their respective conditions expression list are fulfilled.

OR-Triggers execute when any one of their conditions is true. To make OR-Triggers you simply have to add a few conditions to the conditions list e.g. in our example: "pond", "frog", "Plop". The trigger will now also execute on lines like this: "A frog is green" or "You hear a loud Plop!" because "frog" matched in the first line and "Plop" matched in the second line.

Multiline / AND triggers execute when all of their conditions are true. Taking the previous patterns of "pond", "frog", "Plop" and clicking the 'AND' button will make the trigger not fire on "A frog is green" or "You hear a loud Plop!" anymore, because all 3 patterns don't match. It however would fire on "In a brown pond, the frog said Plop!" because all 3 patterns matched. As you might have noticed, all 3 patterns are on the same line: this means that in a multiline/AND trigger, the next pattern starts matching on the same line to make this work.

To make the engine skip lines in a multiline / AND trigger, use the line spacer pattern: select 'line spacer' as the type and put in a number on the left to make it go to the next X lines, for example 1 will make it go to the next line.

The simplest form of AND-Triggers in Mudlet are Trigger Chains or Filter Chains, whatever you’d like to call it.

Any of the patterns in this trigger can match for it to fire

All of the patterns have to match for it to fire. This is a common example of a "shielded regex" - don't run the expensive regex all the time unless you really need to, and match on the faster begin of line the majority of the time

Trigger Chains & Filter Chains

"Chains" and "filters" are different trigger group entities in Mudlet and serve completely different ends.

Chains

A chain is defined in Mudlet by making a trigger group and adding a trigger pattern to the group. A group without a pattern is a simple trigger group that serves no other purposes than adding structure to your trigger system in order to organize your triggers better. Such a normal trigger group will always grant access to its children unless it has been explicitly disabled (= all access to itself or any of its children is locked) either manually or by a script.

A trigger group with a defined trigger pattern, however, will behave like a normal trigger and match if the pattern matches. Such a trigger group is called "chain head". A chain head will only grant access to its children if the trigger pattern has matched and the chain has been enabled. Thus, chains can be looked at as a mechanism to automatically enable and disable triggers or groups of triggers when a certain condition has been met i. e. the trigger pattern of the chain head has been matched. (However, technically this is not correct as disabled child triggers will not be invoked if the chain head matches. In other words, in chains you can still have enabled/disabled elements. The idea of a chain can better be described by necessary and sufficient condition - both of which need to be met before a child trigger is being run.)

Adding child triggers to this group will add elements to the trigger chain. These chain elements will only be activated if the chain head has matched before and thus opened the trigger chain. The chain stays open until the "keep chain open for x lines" value has been reached. The default is 0 which means that the chain only stays open for the current line. When access to the chain has been granted all child triggers will be tested against the content of the current line. Consequently, trigger chains are a means to automatically enable/disable trigger groups without the hassle of enabling and disabling trigger groups manually. This has 2 important advantages: Chains are faster than conventional solutions and chains reduce the complexity of your scripts and greatly reduce the usual system bugs that inevitably go along with enable/disable trigger xy function calls as it’s very difficult and error prone to enable and disable your triggers correctly in large complex trigger systems. This is one of the most powerful features in Mudlet and should be used whenever possible.

Let’s look at a practical example for a trigger chain:

My newbie prompt on Achaea looks like this 500h, 500m ex- when I have balance and 500h, 500m e- when I have lost balance. We are going to develop a prompt detection trigger that raises the event gotPrompt and sets the variables myBalance=true or myBalance=false To begin with, we add a new trigger group and add the Perl regex pattern to detect the prompt:

^(\d+)h, (\d+)m

The pattern reads in plain English: At the beginning of a prompt line there are is a number directly followed by the letter h, a comma, a space and another number followed by the letter h. Whenever this pattern matches the trigger will fire and we’ll know that we have a prompt line. We use the 2 numbers that we captured in our pattern to update our health and mana stats.

Detecting balance is more difficult as balance is indicated by the letters ex- on the same line after the prompt and imbalance is indicated by the letters e-. As we have set a pattern in a trigger group (folder), the folder is turned into a trigger chain head. It will now only let data through to its children when its own pattern is matched. In other words, the child triggers of the trigger chain will only receive data on prompt lines. We are going to take advantage of this by adding two simple substring triggers to detect balance and imbalance. The balance trigger pattern is ex- and the imbalance detector pattern is e-.

In the two balance detection triggers we now write myBalance=false and myBalance=true respectively plus a little echo on the screen that shows our current balance status.

We could now add a call deleteLine() to the prompt detection trigger to erase the prompt from the screen if we don’t want to see it as we have computed all relevant information.

Filters

You can turn a trigger chain head into a filter by checking the "only pass matches" option. This changes the content of what is forwarded as trigger text to the children triggers in the chain. Chains forward the content of the current line as trigger text whereas filters forward the matched pattern instead of the current line. In other words, the text of the current line is filtered according to the pattern of the filter. For example: You want to know the exits in the current room. The simplest solution is a simple filter on You see exits to: (.*) Then you simply add triggers to the filter chain such as north, south, west, east etc. The direction triggers will only be called if the filter head has matched.

Imagine the following scenario: You want to collect some berries. You know that the room contains some berries if the room description contains the words "You are inside a forest. There are some strawberries." or "You are inside a forest. There are some blackberries." and there are always only one kind of berry in the room. You make a new substring trigger for this line, but instead of choosing a regular trigger, you chose to add a new trigger group. Now you add You are inside a forest\. There are some (\w+)\. as an Regular Expression to the expression list of the trigger group. When adding conditions to a trigger group, the trigger group turns from an organizational unit into a filter unit, if the "filter" option is checked. From now on this folder is a filter and will only let its matches pass through. In our case this is exactly what we want, because we don’t want to collect all sorts of berries, but we only want 2 particular kinds, namely, strawberries and blackberries, and we know that these berries can only be trusted if they are picked inside a forest as other areas may contain contaminated berries. Now you add two regular triggers to our berry-in-the-forest filter - one containing the condition: strawberries and the other one blackberries. Then we add the commands to pick the particular kind of berry to both triggers (send field). Now what happens is that as soon as a room description reads "You are inside a forest. There are some strawberries/blackberries." the filter will let the kind of berry pass through to our two berry triggers and they will issue commands to pick berries, if there are such berries. However, in any other situation the words "strawberries" and "blackberries" will NOT trigger a pick - only in the above scenario when the filter parent’s condition is met. This is a very nice way to solve complicated problems with a few easy filter chains. This example is trivial, but using filter chains will rapidly show you how formerly complicated things that could only be solved with very complicated regular expressions can be solved easily now with a couple of filter chains.

Named Capture Patterns

You can use named patterns - that is, giving your captures names instead of [2], [3], [4] numbers - by adding ?<variablename> to your capture in Mudlet 4.11+:

-- before: 
(\w+) = matches[2]

-- now:
(?<name>\w+) = matches.name or matches["name"]
(?<weapon>\w+) = matches.weapon or matches["weapon"]

This can be particularly handy if you have several patterns in a trigger and the location of matches[n] moves around. Try this out in a demo package.

Named capture groups still will be available under their respective number in matches.

You can programatically check if your Mudlet supports this feature with mudlet.supports.namedPatterns.

Example:

Let's assume we want to capture name and class of character, but MUD outputs it two ways.

1. My name is Dargoth. My class is a warrior.
2. I am a wizard and my name is Delwing.

Instead of creating two different triggers we can create only one containing alternative matching patterns:

1. ^My name is (?<name>\w+)\. My class is a (?<class>\w+)\.
2. ^I am a (?<class>\w+)\ and my name is (?<name>\w+)\.

Notice that class and name come in different order, therefore in first case we will have name under matches[2] and in second case under matches[3]. With named capture groups in both cases we will have name available under matches.name and class under matches.class.

Code example to handle named matches above:

  echo("Name: " .. matches.name .. "\n")
  echo("Class: " .. matches.class .. "\n")

Note: To verify whether named groups are available you can use flag mudlet.supports.namedGroups.

Advanced Lua

Lua version

Mudlet uses Lua 5.1.

Lua tables

A good overview of tables is available on Lua's wiki in the TablesTutorial. Nick Gammon has also written a nice overview on how to deal with Lua tables.

Creating Tables

Tables can be created manually, by scripting or by a return value from a function (e.g. getRoomExits())

-- create a simple table
local myTable = { value1, value2, value3 }
local exits = { "north", "south", "west" }

-- create a table with keys in uses the following format
local myTable = { key1 = value1, key2 = value2, key3 = value3 }
local stats = { hp = 1234, mana = 321, moves = 678 }

Tables can also be a mixture of the above!

Accessing Tables

There are a number of different ways to access tables and it depends on how they are created.

Here are a few examples from the tables created above.

  print(exits[1])     -- will display north, tables start indexing at position 1
  print(stats["hp"])  -- will display 1234
  print(stats.hp)     -- will display 1234, a shorthand method
  print(stats[1])     -- will return nothing (or nil), there is no key called 1

Assigning Values to Table Elements

Now you know how to access table elements, addressing and assigning values to them works in the same way as normal variables.

  
stats["hp"] = 2000
-- or -- stats.hp = 2000
exits[1] = "down"

-- create a new entry in the stats table with the key called gold and assign it the value of 35
stats["gold"] = 35

Deleting a Table Element

Assigning an element the value of nil will remove it entirely.

stats["gold"] = nil
-- the stats table now only contains hp, mana and moves

See also: Table Functions API

How to use multimatches[n][m]

multimatches[n][m] is the complement of matches[n] when matching multi-line triggers. multimatches[n][m] stores its matches by lines, inside each line are the relevant matches to it. The following example can be tested on the game batmud.bat.org:

In the case of a multiline trigger with these 2 Perl regex as conditions:

^You have (\w+) (\w+) (\w+) (\w+)

^You are (\w+).*(\w+).*

The command "score" generates the following output on batMUD:

 You have an almost non-existent ability for avoiding hits.
 You are irreproachably kind.
 You have not completed any quests.
 You are refreshed, hungry, very young and brave.
 Conquer leads the human race.
 Hp:295/295 Sp:132/132 Ep:182/181 Exp:269 >

If you add this script to the trigger:

showMultimatches()

The script, i.e. the call to the function showMultimatches() generates this output:

 -------------------------------------------------------
 The table multimatches[n][m] contains:
 -------------------------------------------------------
 regex 1 captured: (multimatches[1][1-n])
           key=1 value=You have not completed any quests
           key=2 value=not
           key=3 value=completed
           key=4 value=any
           key=5 value=quests
 regex 2 captured: (multimatches[2][1-n])
           key=1 value=You are refreshed, hungry, very young and brave
           key=2 value=refreshed
           key=3 value=young
           key=4 value=and
           key=5 value=brave
 -------------------------------------------------------

The function showMultimatches() prints out the content of the table multimatches[n][m]. You can now see what the table multimatches[][] contains in this case. The first trigger condition (=regex 1) got as the first full match "You have not completed any quests". This is stored in multimatches[1][1] as the value of key=1 in the sub-table matches[1] which, in turn, is the value of key=1 of the table multimatches[n][m].

The structure of the table multimatches:

multimatches {
                1 = {
                       matches[1] of regex 1
                       matches[2] of regex 1
                       matches[3] of regex 1
                              ...
                       matches[m] of regex 1 },
                2 = {
                       matches[1] of regex 2
                       matches[2] of regex 2
                             ...
                       matches[m] of regex 2 },
                 ...         ...
                n = {
                       matches[1] of regex n
                       matches[2] of regex n
                             ...
                       matches[m] of regex n }
}

The sub-table matches[n] is the same table matches[n] you get when you have a standard non-multiline trigger. The value of the first key, i. e. matches[1], holds the first complete match of the regex. Subsequent keys hold the respective capture groups. For example: Let regex = "You have (\d+) gold and (\d+) silver" and the text from the game = "You have 5 gold and 7 silver coins in your bag." Then matches[1] contains "You have 5 gold and 7 silver", matches[2] = "5" and matches[3] = "7". In your script you could do:

myGold = myGold + tonumber( matches[2] )
mySilver = mySilver + tonumber( matches[3] )

However, if you’d like to use this script in the context of a multiline trigger, matches[] would not be defined as there are more than one regex. You need to use multimatches[n][m] in multiline triggers. Above script would look like this if above regex would be the first regex in the multiline trigger:

myGold = myGold + tonumber( multimatches[1][2] )
mySilver = mySilver + tonumber( multimatches[1][3] )

What makes multiline triggers really shine is the ability to react to game output that is spread over multiple lines and only fire the action (=run the script) if all conditions have been fulfilled in the specified amount of lines.

Regex in Lua

Lua has its own, fast and lightweight pattern matching built in - see 20.2 – Patterns. Should you need proper regex however, Mudlet has lrexlib available - which works as a drop-in replacement; replace string. with rex. - for example string.gsub to rex.gsub. See manual for documentation.

-- example: strip out trailing .0's from text using a regex
local stripped = rex.gsub("1.0.0", [[(\.0+)+$]], '')
print(stripped)

The lrexlib manual can be hard to read, so the instructions in this section should provide most of what you need.

lrexlib comes preinstalled in Mudlet and it is automatically bounded to the rex variable, as the rex_pcre version. If you want to test your lua code outside Mudlet, you have to install it yourself. The easiest installation method uses luarocks. There are a few flavors that you can specify, but in this section we will focus on the POSIX and PCRE flavors.

luarocks install --local lrexlib-POSIX
luarocks install --local lrexlib-PCRE

After installation, you can use the library:

> local rex = require("rex_posix")

If you set the flavor to rex_pcre, your code should work afterwards in Mudlet.

Keep in mind that precomputing a pattern with the new function has the advantage that objects resulted will be garbage collected and that regexes are greedy by default.

Another thing that may surprise some users is that, when escaping, you need to backslashes:

> rex.match("The answer is 42", "(\\d+)")

You can also achieve this using long string literal syntax, where you don't need the double escape:

> rex.match("The answer is 42", [[(\d+)]])

There are a few functions that you need to know: gsub, count, split, find, match.

count

The count function counts the matches:

> print(rex.count("ab", "."))
2

A single dot here has the same meaning it has in POSIX regexes.

You can also precompute the pattern, using the new function:

> print(rex.count("ab", rex.new"."))
2

Remember that regexes are greedy by default:

> print(rex.count("aaa", ".*"))
1

split

The split function splits a string according to a regex pattern:

> for a in rex.split("aba", "b") do
print(a)
end
a
a

> for a in rex.split("aba", ",") do
print(a)
end
aba

Be careful though, because while the split consumes all the characters with the same value, if they are adjacent, you will also have the borders between them resulting in an empty string:

> for a in rex.split("abba", "b") do
print(a)
end
a

a

find

The find function searches for the first match, and returns the offsets where the match starts and ends.

> print(rex.find("aaa", "b"))
nil

> print(rex.find("aba", "b"))
2	2

find also takes an additional parameter, which is the starting position:

> print(rex.find("abab", "b"))
2	2
> print(rex.find("abab", "b", 3))
4	4

A negative starting position will circle back from the end:

> print(rex.find("ababab", "b", -1))
6	6
> print(rex.find("ababab", "b", -3))
4	4

match

The match function works similarly to the find function, but returns the matches instead of the indices:

> print(rex.match("abcdef", "ab"))
ab
> print(rex.match("abcdef", ".*"))
abcdef
> print(rex.match("abcdef", "ab.."))
abcd
> print(rex.match("abcdef", ".*", 3))
cdef
> print(rex.match("abcdef", ".*", -3))
def

gsub

The gsub function replaces the pattern in the string, with the value in the third parameter:

> print(rex.gsub("abcdef", "[abef]+", ""))
cd	2	2

This snippet replaces all the "a", "b", "e" or "f" characters with the empty string, so only "c" and "d" remain.

The fourth parameter determines how many replacements are made:

> print(rex.gsub("abcdef", "[abef]+", "", 1))
cdef	1	1

Because the regex is greedy, the "ab" is a single match, so it gets replaced.

PCRE specific functionality

The case insensitive flag:

> rex = require("rex_pcre")
> flags = rex.flags()
> print(rex.find("ABab", "a", 0, flags.CASELESS))
1	1

Coroutines

Mudlet supports Lua's coroutines starting with 3.2.0, which opens up a whole lot of possibilities for the way you program your scripts. A pretty technical description and a tutorial is available, but for a quick explanation, think of coroutines allowing you to pause and resume running a function. If you're familiar with other clients, it is something like a #wait statement where a script will stop running, except unlike a #wait which auto-resumes the script later, you resume it when it yourself whenever you'd like.

Here's an example - add this code as a new script:

function ritual()
  send("get wood")
  -- think of coroutine.yield as yielding (giving away) control,
  -- so the function will stop here and resume on making fire 
  -- when called the next time
  coroutine.yield()
  send("make fire")
  coroutine.yield()
  send("jump around")
  coroutine.yield()
  send("sacrifice goat")
end

Make a ^ritual$ alias - which seems big, but that's just because there's a lot of explanation inside it:

-- create a coroutine that'll be running our ritual function
-- or re-use the one we're already using if there is one
ritualcoroutine = ritualcoroutine or coroutine.create(ritual)

-- run the coroutine until a coroutine.yield() and see
-- if there's any more code to run
local moretocome = coroutine.resume(ritualcoroutine)

-- if there's no more code to run - remove the coroutine,
-- so next time you call the alias - a new one gets made
if not moretocome then
  ritualcoroutine = nil
end

Now try doing the ritual command. You'll see that the send()'s are being sent one at a time, instead of all at once as they would have been without the yields. Cool, huh?

You can also install the demo as a package - paste this into Mudlet:

lua installPackage("http://wiki.mudlet.org/images/3/36/Ritual-coroutine-demo.zip")

Note that if you'll be using coroutines as part of a package you'll give to others, remember about the if mudlet.supports.coroutines then return end bit. Older Mudlets that don't support coroutines might crash, which sucks. Newer ones that do support them are completely fine, however!

Coroutines have many uses: finite state machines, running intensive tasks (yielding every once in a while so Mudlet isn't frozen), and so on.

Batching Processing with Coroutines

Say you want to process large jobs that lock up the user interface for the duration of the job, such as colouring entire maps, deleting rooms or processing large files. You can process these jobs in small amounts and then yield to the main loop where you can display a progress meter.

local function task()

  -- process a large task, like colouring all rooms in a map
  for i = 1, 100 do
    -- setRoomEnv(i, ...)                  -- perform a small part of the job, colour just one room
    echo("processed part of a task.. ")
    coroutine.yield()                      -- now yield to the progress meter function
  end
end

function batch()

  local routine = coroutine.create(task)
  
  for i = 0, 100 do
    coroutine.resume(routine, i)
    echo(i .. "% complete.\n")    
  end
end

All running lua batch() you will see;

processed part of a task.. 0% complete.
processed part of a task.. 1% complete.
processed part of a task.. 2% complete.
processed part of a task.. 3% complete.
processed part of a task.. 4% complete.
processed part of a task.. 5% complete.

...

Introspective facilities

Lua brings a helpful debug.getinfo(function) function, which gets you some information about where a function comes from: whenever it's your own, or one defined by Mudlet (in C++ or Lua). You can also use it to get more information on the Alias## / Trigger## objects you see in the error console:

If you're working on coding Mudlet itself, use this function to tell where the actual definition of a function is.

Event System

Events in Mudlet allow a paradigm of system-building that is easy to maintain (because if you’d like to restructure something, you’d have to do less work), enables interoperability (making a collection of scripts that work with each other is easier) and enables an event-based way of programming.

The essentials of it are as such: you use Scripts to define which events a function should listen to, and when the event is raised, the said function(s) will be called. Events can also have function parameters with them, which’ll be passed onto the receiving functions.

Registering an event handler via UI

Registering an event handler means that you’ll be telling Mudlet what function it should call for you when an event is raised, so it’s a two step process - you need to tell it both what function you’d like to have called, and on what event it should be called.

To tell it what function should be called, create a new script, and give the script the name of the function you’d like to be called. This is the only time where an items name matters in Mudlet. You can define the function right inside the script as well, if you’d like.

Next, we tell it what event or events this function should be called on - you can add multiple entries. To do that, enter the events name in the Add User Defined Event Handler: field, press enter, and it’ll go into the list - and that is all.

Registering an event from a script

You can also register your event with the registerAnonymousEventHandler(event name, function reference, [one shot]) function inside your scripts:

-- example taken from the God Wars 2 (http://godwars2.org) Mudlet UI - forces the window to keep to a certain size
function keepStaticSize()
  setMainWindowSize(1280,720)
end -- keepStaticSize

registerAnonymousEventHandler("sysWindowResizeEvent", keepStaticSize, false)

Note: : registerNamedEventHandler can also be used. Doing so causes Mudlet to handle saving of the IDs for you.

Note: Mudlet also uses the event system in-game protocols (like GMCP, MSDP and others).

Raising a custom event

To raise an event, you'd use the raiseEvent() function:

raiseEvent(name, [arguments...])

It takes an event name as the first argument, and then any amount of arguments after it which will be passed onto the receiving functions.

Example of registering and raising an event

Add a script to each profile you need the event.

-- This is the function that will be called when the event is raised.
-- "event" is set to the event name.
-- "arg" is the argument(s) provided with raiseEvent/raiseGlobalEvent.
-- "profile" - Is the profile name from where the raiseGlobalEvent was triggered from
--             It is 'nil' if raiseEvent() was used.
function onMyEvent(event, arg, profile)
  echo("Event: " .. event .. "\n")
  echo("Arg  : " .. arg .. "\n")
  -- If the event is not raised with raiseGlobalEvent() profile will be 'nil'
  echo("Profile: " .. (profile or "Local") .. "\n")
end

-- Register the event handler.
registerAnonymousEventHandler("my_event", onMyEvent)

To raise the event you can call:

-- Trigger only in the current profile:
raiseEvent("my_event", "Hello world!")

-- Trigger the event in all OTHER profiles:
raiseGlobalEvent("my_event", "Hello World!")

To review, count and extract from an unknown number of arguments received by an event:

function eventArgs(...)
  local args = {...}
  local amount = #args
  local first = args[1]
  echo("Number of arguments: " .. amount)
  echo("\nTable of all arguments: ")
  display(args)
  echo("First argument: " .. first)
  echo("\n\n")
end

Gamepad functionality

Note: will be removed in 4.18 as this is blocking Mudlet updates and is not used by players.

Gamepad functions are not fully supported with all operating systems and hardware. Windows supports XInput devices like Xbox 360 and Xbox One controllers. DirectInput controllers like a PlayStation 4 controller can be translated to XInput with third party software. Mudlet on Linux can support gamepads but only if you compile it yourself. The automated builds are made using the oldest supported version of Ubuntu, and the Qt5 gamepad module was not available on Ubuntu 18.04 LTS.

Mudlet-raised events

Mudlet itself also creates events for your scripts to hook on. The following events are generated currently:

AdjustableContainerReposition

Raised while a adjustable container is re-positioned.

function repositioningContainer(eventName, containerName, width, height, x, y, mouseAction)
  print(f"{containerName}: {x}x, {y}y, {width}x{height}, using mouse? {mouseAction}")
end

registerAnonymousEventHandler("AdjustableContainerReposition", repositioningContainer)

AdjustableContainerRepositionFinish

Raised when an adjustable container done being re-positioned.

function finishedRepositioning(eventName, containerName, width, height, x, y)
  print(f"{containerName}: {x}x, {y}y, {width}x{height}")
end

registerAnonymousEventHandler("AdjustableContainerRepositionFinish", finishedRepositioning)

channel102Message

Raised when a telnet sub-option 102 message is received (which comprises of two numbers passed in the event). This is of particular use with the Aardwolf MUD who originated this protocol. See this forum topic for more about the Mudlet Aardwolf GUI that makes use of this.

mapModeChangeEvent

Raised when the mapper is switching between "view-only" and "editing" mode of the Visual Map Editor. A value of "editing" or "viewing" will be given as argument to indicate which mode was entered.

mapOpenEvent

Raised when the mapper is opened - either the floating dock or the in-Mudlet widget.

sysAppStyleSheetChange

Raised when setAppStyleSheet is called and a new stylesheet applied to Mudlet.

-- This will respond to a future (as yet unpublished) addition to the Mudlet code that will allow some
-- of a default application style sheet to be supplied with Mudlet to compensate for some text colors
-- that do not show up equally well in both light and dark desktop themes. That, perhaps, might finally
-- allow different colored texts to be uses again for the trigger item types!
function appStyleSheetChangeEvent( event, tag, source )
  if source == "system" then
    colorTable = colorTable or {}
    if tag == "mudlet-dark-theme" then
      colorTable.blue = {64, 64, 255}
      colorTable.green = {0, 255, 0}
    elseif tag == "mudlet-light-theme" then
      colorTable.blue = {0, 0, 255}
      colorTable.green = {64, 255, 64}
    end
  end
end

Available in Mudlet3.19+

sysBufferShrinkEvent

Raised when the oldest lines are removed from the back of any console or buffer belonging to a profile because it has reached the limit (either the default or that set by setConsoleBufferSize). The two additional arguments within the event are: the name of the console or buffer and the number of lines removed from the beginning of the buffer. This information will be useful for any situation where a line number is being stored as it will need to be decremented by that number of lines in order to continue to refer to the same line (assuming that it is still present - indicated by the number remaining positive) after the oldest ones have been removed.

Available in Mudlet4.17+

sysConnectionEvent

Raised when the profile becomes connected to a MUD.

sysCustomHttpDone

Raised whenever a customHTTP() request completes successfully. Arguments with the event are the URL that the request was sent to and the response body (if it's less than 10k characters) and HTTP method.

See also sysCustomHttpError.

sysCustomHttpError

Raised whenever a customHTTP() request fails. Arguments are the error message and the URL that the request was sent to and HTTP method.

See also sysCustomHttpDone.

sysDataSendRequest

Raised right before a command from the send(), sendAll() functions or the command line is sent to the game - useful for keeping track of what your last command was, manipulating input or even denying the command to be sent if necessary with denyCurrentSend().

sysDataSendRequest will send the event name and the command sent (in string form) to the functions registered to it. IE: commandSent in the example below will be "eat hambuger" if the user entered only that into command line and pressed enter, send("eat hamburger"), sendAll("eat humburger", "eat fish") or sendAll("eat fish", "eat humburger")

Note: if you'll be making use of denyCurrentSend(), you really should notify the user that you denied their command - unexperienced ones might conclude that your script or Mudlet is buggy if they don't see visual feedback. Do not mis-use this and use it as keylogger either.

-- cancels all "eat hambuger" commands
function cancelEatHamburger(eventName, commandSent)
  if commandSent == "eat hamburger" then
    denyCurrentSend() --cancels the command sent.
    cecho("<red>Denied! You can't do "..commandSent.." right now.\n")
  end --if commandSent == eat hamburger
end

registerAnonymousEventHandler("sysDataSendRequest", cancelEatHamburger)

If you wanted to control input you could set a bool after a trigger. This is useful if you want alias like control, do not know what text will be entered, but do know a trigger that WILL occur just before the user enters the command.

function controlInput(_, command) 
  if changeCMDInput then
    changeCMDInput = false --set this if check to false to it doesn't occur every input
    --Also set the bool check BEFORE any send() functions within a sysDataSendRequest function
    sendAll(command .. "some target", command .. "some other target", true) --Duplicate and unknown command
    denyCurrentSend() --Deny the original command, not the commands sent with sendAll.
  end
end
registerAnonymousEventHandler("sysDataSendRequest", controlInput)

Take note that functions registered under sysDataSendRequest WILL trigger with ALL commands that are sent.

sysDeleteHttpDone

Raised whenever a deleteHTTP() request completes successfully. Arguments with the event are the URL that the request was sent to and the response body (if it's less than 10k characters).

See also sysDeleteHttpError.

sysDeleteHttpError

Raised whenever a deleteHTTP() request fails. Arguments are the error message and the URL that the request was sent to.

See also sysDeleteHttpDone.

sysDisconnectionEvent

Raised when the profile becomes disconnected, either manually or by the game.

If you'd like to automatically reconnect when you get disconnected, make a new Script and add this inside:

registerAnonymousEventHandler("sysDisconnectionEvent", reconnect)

sysDownloadDone

Raised when Mudlet is finished downloading a file successfully - the location of the downloaded file is passed as a second argument, the file size is passed as the third, and the HTTP response is passed as the fourth.

Example - put it into a new script and save it to run:

-- create a function to parse the downloaded webpage and display a result
function downloaded_file(_, filename)
  -- is the file that downloaded ours?
  if not filename:find("achaea-who-count.html", 1, true) then return end

  -- read the contents of the webpage in
  local f, s, webpage = io.open(filename)
  if f then webpage = f:read("*a"); io.close(f) end
  -- delete the file on disk, don't clutter
  os.remove(filename)

  -- parse our downloaded file for the player count
  local pc = webpage:match([[Total: (%d+) players online]])
  display("Achaea has "..tostring(pc).." players on right now.")
end

-- register our function to run on the event that something was downloaded
registerAnonymousEventHandler("sysDownloadDone", downloaded_file)

-- download a list of fake users for a demo
downloadFile(getMudletHomeDir().."/achaea-who-count.html", "https://www.achaea.com/game/who")

You should see a result like this:

sysDownloadError

Raised when downloading a file failed - the second argument contains the error message, the third the local filename that was to be used and the actual URL used (might not be the same as what was given if redirection took place).

Example

--if a download fails notify the player.
function downloadErrorEventHandler(event, errorFound, localFilename, usedUrl)
    cecho("fuction downloadErrorEventHandler, "..errorFound)
    debugc("fuction downloadErrorEventHandler, "..errorFound) --display to error screen in editor
end --function downloadErrorEventHandler
registerAnonymousEventHandler("sysDownloadError", downloadErrorEventHandler)

sysDownloadFileProgress

Raised while file is being downloaded to indicate progess of download.

The arguments passed areː: event name, url of download, bytes downloaded, total bytes (if available).

Example

-- will show progress bar while download file and hide it after file download is complete
local progressBar = Geyser.Gauge:new({
  name="downloadProgressBar",
  x="25%", y="10%",
  width="50%", height="5%",
})
progressBar:setFontSize(13)
progressBar:setAlignment("center")
progressBar:hide()


local fileUrl = "https://www.mudlet.org/download/Mudlet-4.10.1-linux-x64.AppImage.tar"
local targetFile = getMudletHomeDir() .. "/Mudlet.tar"
function handleProgress(_, url, bytesDownloaded, totalBytes)
  if url ~= fileUrl then
    return
  end
  
  progressBar:show()
  
  if not totalBytes then
    bytesDownloaded = 0
    totalBytes = 1
  end
  
  progressBar:setValue(bytesDownloaded, totalBytes, math.floor((bytesDownloaded / totalBytes) * 100) .. "%")
end

registerAnonymousEventHandler("sysDownloadFileProgress", handleProgress)

function hideProgressBar()
  tempTimer(3, function() progressBar:hide() end)
end 

registerAnonymousEventHandler("sysDownloadDone", hideProgressBar)
registerAnonymousEventHandler("sysDownloadError", hideProgressBar)

downloadFile(targetFile, fileUrl)

Available in Mudlet4.11+

sysDropEvent

Raised when a file is dropped on the Mudlet main window or a userwindow. The arguments passed areː filepath, suffix, xpos, ypos, and consolename - "main" for the main window and otherwise of the userwindow/miniconsole name.

Available in Mudlet4.8+

function onDragAndDrop(_, filepath, suffix, xpos, ypos, consolename)
  print(string.format("Dropped new file into %s: %s (suffix: %s)", consolename, filepath, suffix))
end
registerAnonymousEventHandler("sysDropEvent", onDragAndDrop)

sysDropUrlEvent

Raised when a url is dropped on the Mudlet main window or a userwindow. As an url at the moment Mudlet understands The arguments passed areː url, schema, xpos, ypos, and consolename - "main" for the main window and otherwise of the userwindow/miniconsole name.

Available in Mudlet4.11+

function onDragAndDropUrl(_, url, schema, xpos, ypos, consolename)
  print(string.format("Dropped new url into %s: %s (suffix: %s)", consolename, filepath, suffix))
  if schema == "http" or schema == "https" then
    print("\nOh boy... this might be a link to some website")
  end
end
registerAnonymousEventHandler("sysDropUrlEvent", onDragAndDropUrl)

sysExitEvent

Raised when Mudlet is shutting down the profile - a good event to hook onto for saving all of your data.

sysGetHttpDone

Raised whenever a getHTTP() request completes successfully. Arguments with the event are the URL that the request was sent to and the response body (if it's less than 10k characters).

This event is also raised when a post/put/delete request redirects to a GET.

See also sysGetHttpError.

Available in Mudlet4.10+

sysGetHttpError

Raised whenever a getHTTP() request fails. Arguments are the error message and the URL that the request was sent to.

See also sysGetHttpDone.

Available in Mudlet4.10+

sysInstall

Raised right after a module or package is installed by any means. This can be used to display post-installation information or setup things.

Event handlers receive the name of the installed package or module as additional argument.

Note: Installed modules will raise this event handler each time the synced profile is opened. sysInstallModule and sysInstallPackage are not raised by opening profiles.

Available in Mudlet3.1+

function myScriptInstalled(_, name)
  -- stop if what got installed isn't my thing
  if name ~= "my script name here" then return end

  print("Hey, thanks for installing my thing!")
end
registerAnonymousEventHandler("sysInstallPackage", myScriptInstalled)

sysInstallModule

Raised right after a module is installed through the module dialog. This can be used to display post-installation information or setup things.

See also sysLuaInstallModule for when a module is installed via Lua.

Event handlers receive the name of the installed module as well as the file name as additional arguments.

Available in Mudlet3.1+

sysInstallPackage

Raised right after a package is installed by any means. This can be used to display post-installation information or setup things.

Event handlers receive the name of the installed package as well as the file name as additional arguments.

Available in Mudlet3.1+

sysIrcMessage

Raised when the IRC client receives an IRC message. The sender's name, channel name, and their message are passed as arguments to this event.

Starting with Mudlet 3.3, this event changes slightly to provide more information from IRC network messages. Data such as status codes, command responses, or error messages sent by the IRC Server may be formatted as plain text by the client and posted to lua via this event.

• sender: may be the nick name of an IRC user or the name of the IRC server host, as retrievable by getIrcConnectedHost()
• channel: may not always contain a channel name, but will be the name of the target/recipient of a message or action. In some networks the name may be that of a service (like "Auth" for example)

Example

function onIrcMessage(_, sender, target, message)
  echo(string.format('(%s) %s says, "%s"\n', target, sender, message))
end

registerAnonymousEventHandler("sysIrcMessage", onIrcMessage)

To send a message, see sendIrc().

sysLabelDeleted

Raised after a label is deleted, with the former label's name as an argument.

sysLoadEvent

Raised after Mudlet is done loading the profile, after all of the scripts, packages, and modules are installed. Note that when it does so, it also compiles and runs all scripts - which could be a good idea to initialize everything at once, but beware - scripts are also run when saved. Hence, hooking only on the sysLoadEvent would prevent multiple re-loads as you’re editing the script.

sysLuaInstallModule

Raised right after a module is installed through the Lua installModule() command. This can be used to display post-installation information or setup things.

Event handlers receive the name of the installed module as well as the file name as additional arguments.

Available in Mudlet3.1+

sysLuaUninstallModule

Raised right before a module is removed through the lua uninstallModule command. This can be used to display post-removal information or for cleanup.

Event handlers receive the name of the removed module as additional argument.

Available in Mudlet3.1+

sysManualLocationSetEvent

Raised whenever the "set location" command (on the 2D mapper context menu) is used to reposition the current "player room". It provides the room ID of the new room ID that the player has been moved to.

Available in Mudlet3.0+

sysMapAreaChanged

Raised whenever the area being viewed in the mapper changes, it returns two additional arguments being the areaID numbers being changed to and the previously viewed area.

Available in Mudlet4.17.0+

sysMapDownloadEvent

Raised whenever an MMP map is downloaded and loaded in.

sysMediaFinished

Raised when media finishes playing. This can be used in a music player for example to start the next song.

Event handlers receive the media file name and the file path as additional arguments.

Available in Mudlet4.15+

sysPathChanged

Raised whenever file or directory added through addFileWatch() is modified.

For directories this event is emitted when the directory at a specified path is modified (e.g., when a file is added or deleted) or removed from disk. Note that if there are several changes during a short period of time, some of the changes might not emit this signal. However, the last change in the sequence of changes will always generate this signal.

For files this event is emitted when the file at the specified path is modified, renamed or removed from disk.

Available in Mudlet4.12+

Example

herbs = {}
local herbsPath = getMudletHomeDir() .. "/herbs.lua"
function herbsChangedHandler(_, path)
  if path == herbsPath then
    table.load(herbsPath, herbs)
    removeFileWatch(herbsPath)
  end
end

addFileWatch(herbsPath)
registerAnonymousEventHandler("sysPathChanged", herbsChangedHandler)

sysPostHttpDone

Raised whenever a postHTTP() request completes successfully. Arguments with the event are the URL that the request was sent to and the response body (if it's less than 10k characters).

See also sysPostHttpError.

sysPostHttpError

Raised whenever a postHTTP() request fails. Arguments are the error message and the URL that the request was sent to.

See also sysPostHttpDone.

sysProfileFocusChangeEvent

Raised whenever a profile becomes or stops being the foreground one when multi-playing, whether multi-view (show all profiles side-by-side) is active or not. The event comes with a second boolean argument which is true if the profile is now the one that has the focus, i.e. will receive keystrokes entered from the keyboard, or false if the focus has just switched from it to another profile.

Available in Mudlet4.17.0+

sysProtocolDisabled

Raised whenever a communications protocol is disabled, with the protocol name passed as an argument. Current values Mudlet will use for this are: GMCP, MDSP, ATCP, MXP, and channel102.

sysProtocolEnabled

Raised whenever a communications protocol is enabled, with the protocol name passed as an argument. Current values Mudlet will use for this are: GMCP, MDSP, ATCP, MXP, and channel102.

function onProtocolEnabled(_, protocol)
  if protocol == "GMCP" then
    print("GMCP enabled! Now we can use GMCP data.")
  end
end

sysPutHttpDone

Raised whenever a putHTTP() request completes successfully. Arguments with the event are the URL that the request was sent to and the response body (if it's less than 10k characters).

See also sysPutHttpError.

sysPutHttpError

Raised whenever a putHTTP() request fails. Arguments are the error message and the URL that the request was sent to.

See also sysPutHttpDone.

sysSoundFinished

This event is obsolete in Mudlet 4.15. Please replace this with sysMediaFinished()

Available in Mudlet3.1+

sysSpeedwalkFinished

Raised when a speedwalk finishes, either one started by speedwalk() or the generic mapping script

sysSpeedwalkPaused

Raised when a speedwalk is paused, either via pauseSpeedwalk() or the generic mapping script.

sysSpeedwalkResumed

Raised when a speedwalk is resumed after pausing, whether it's the generic mapping script or the resumeSpeedwalk() function

sysSpeedwalkStarted

Raised when a speedwalk is started, either by the speedwalk() function or the generic mapping script

sysSpeedwalkStopped

Raised when a speedwalk is stopped prematurely by stopSpeedwalk() or the generic mapping script

sysSyncInstallModule

Raised right after a module is installed through the "sync" mechanism. This can be used to display post-installation information or setup things.

Event handlers receive the name of the installed module as well as the file name as additional arguments.

Available in Mudlet3.1+

sysSyncUninstallModule

Raised right before a module is removed through the "sync" mechanism. This can be used to display post-removal information or for cleanup.

Event handlers receive the name of the removed module as additional argument.

Available in Mudlet3.1+

sysTelnetEvent

Raised whenever an unsupported telnet option is encountered, allowing you to handle it yourself. The arguments that get passed with the event are type, telnet option, and the message.

sysUninstall

Raised right before a module or package is uninstalled by any means. This can be used to display post-removal information or for cleanup.

Event handlers receive the name of the removed package or module as additional argument.

Available in Mudlet3.1+

sysUninstallModule

Raised right before a module is removed through the module dialog. This can be used to display post-removal information or for cleanup.

Event handlers receive the name of the removed module as additional argument.

Available in Mudlet3.1+

sysUninstallPackage

Raised right before a package is removed by any means. This can be used to display post-removal information or for cleanup.

Event handlers receive the name of the removed package as additional argument.

Available in Mudlet3.1+

sysUnzipDone

Raised when a zip file is successfully unzipped using unzipAsync()

Event handlers receive the zip file name and the unzip path as additional arguments.

Available in Mudlet4.6+

sysUnzipError

Raised when a zip file fails to unzip using unzipAsync()

Event handlers receive the zip file name and the unzip path as additional arguments.

Available in Mudlet4.6+

sysUserWindowResizeEvent

Raised when a userwindow is resized, with the new height and width coordinates and the windowname passed to the event. A common usecase for this event is to move/resize your UI elements according to the new dimensions.

See alsoː sysWindowResizeEvent

Example

This sample code will echo whenever a resize happened with the new dimensions:

function resizeEvent( event, x, y, windowname )
  echo("RESIZE EVENT: event="..event.." x="..x.." y="..y.." windowname="..windowname.."\n")
end

sysWindowMousePressEvent

Raised when a mouse button is pressed down anywhere on the main window (note that a click is composed of a mouse press and mouse release). The button number, the x,y coordinates of the click and the windowname are reported.

Note: Windowname reported in Mudlet 4.9+

See alsoː sysWindowMouseReleaseEvent

Example

function onClickHandler( event, button, x, y, windowname )
  echo("CLICK event:"..event.." button="..button.." x="..x.." y="..y.." windowname="..windowname.."\n")
end

sysWindowMouseReleaseEvent

Raised when a mouse button is released after being pressed down anywhere on the main window (note that a click is composed of a mouse press and mouse release).

See sysWindowMousePressEvent for example use.

sysWindowResizeEvent

Raised when the main window is resized, or when one of the borders is resized, with the new height and width coordinates passed to the event. A common usecase for this event is to move/resize your UI elements according to the new dimensions.

See alsoː sysUserWindowResizeEvent

Example

This sample code will echo whenever a resize happened with the new dimensions:

function resizeEvent( event, x, y )
  echo("RESIZE EVENT: event="..event.." x="..x.." y="..y.."\n")
end

ttsPitchChanged

Raised when text-to-speech function ttsSetPitch(...) has been called.

See also: Manual:Text-to-Speech

ttsRateChanged

Raised when text-to-speech function ttsSetRate(...) has been called.

See also: Manual:Text-to-Speech

ttsSpeechError

Raised when a text-to-speech function encountered an error while changing states (eg. from stopped to playing to pausing). Usually indicated when the operating system TTS engine is not working correctly.

See also: Manual:Text-to-Speech

ttsSpeechPaused

Raised when text-to-speech function ttsPause(...) has been called.

See also: Manual:Text-to-Speech

ttsSpeechQueued

Raised when text-to-speech function ttsQueue(...) has been called.

See also: Manual:Text-to-Speech

ttsSpeechReady

Raised when the text-to-speech engine is ready to beginning processing text.

See also: Manual:Text-to-Speech

ttsSpeechStarted

Raised when text-to-speech functions ttsSpeak(...) or ttsResume(...) have been called.

See also: Manual:Text-to-Speech

ttsVoiceChanged

Raised when text-to-speech functions ttsSetVoiceByIndex(...) or ttsSetVoiceByName(...) have been called.

See also: Manual:Text-to-Speech

ttsVolumeChanged

Raised when text-to-speech function ttsSetVolume(...) has been called.

See also: Manual:Text-to-Speech

Scripting with Mudlet

Lua tables can basically be considered multidimensional arrays and dictionaries at the same time. If we have the table matches, matches[2] is the first element, matches[n+1] the n-th element.

 a = "Tom"
 matches[2] = "Betty"
 b = matches[2]
 c = a .. b and e will equal "TomBetty"

To output a table you can use a convenience function - display(mytable), which is built into Mudlet.

Lua interface functions - triggers, timers etc.

How to get data from regex capture groups? Regular expression capture groups (e.g. "(\d+)" ) are passed on to Lua scripts as a Lua table matches. To make use of this information inside Lua scripts, you need to specify the number of the capture group within the regex.

Example: You have (\d+) weapons and they are (?:(\b\w+\W+)+)

This regex contains 3 capture groups, but only the 2 green colored ones contain data as the red capture group is a non-capturing group. Consequently, your Lua script gets passed only 2 instead of 3 capture groups and matches[4] is undefined.

In your Lua script you may write following program in order to print the number and status of your weapons on the screen:

You have (\d+) weapons and they are (?:(\b\w+\W+)+)

 number_of_weapons = matches[2]
 status_of_weapons = matches[3]
 notice = number_of_weapons .. status_of_weapons
 echo( notice )
 send( "put weapons in backpack" )

 -- the following 2 lines color the first capture
 -- group red and the second group blue
 -- see below for details

 selectCaptureGroup( 2 )
 setFgColor( 255,0,0 )

 selectCaptureGroup( 3 )
 setFgColor( 0,0,255 )

The best way is to use selectCaptureGroup( number ) to select the proper capture group and then perform your actions on it e.g. replace(), highlight etc. Note: Both selectCaptureGroup() and matches[n] start with group 1 (which is the whole match. The defined capture groups start with 2).

How to select all occurrences of "Tom" and highlight them?

You add a function like this to a script containing you main function definitions. Note that script items differ from all other "scripts" in triggers, timers, actions etc. because they require you to put your code in proper functions that can be called by your other trigger-scripts, timer-scripts etc. via normal function calls. Trigger-scripts, timer-scripts etc. cannot contain any function definitions because they are automatically generated functions themselves because this makes usage a lot easier.

To come back to our question how to select all occurrences of "Tom" and highlight them:

  function setBgColorAll( word, r, g, b )
    i = 0
    word_count = 1
    while i > -1 do
        i = selectString(word, word_count)
        if i == -1 then
             return
        end
        word_count = word_count +1
        setBgColor( r, g, b )
    end
  end

Then you simply define a substring matching trigger on the word "Tom" and in the trigger script you call above function:

setBgColorAll("Tom", 255,50,50)

Since Mudlet 4.11+ it is possible to use name capture groups. You can verify if feature availability by checking mudlet.supports.namedPatterns flag. Let's say you have multiple patterns that you want to handle with one code.

^My name is (?<name>\w+)\. My class is (?<class>\w+)\.

^I am (?<class\w+)\ and my name is (?<name>\w+)\.

Notice that class and name come in different order, therefore in first case we will have name under matches[2] and in second case under matches[3]. With named capture groups in both cases we will have name available under matches.name and class under matches.class.

Code example to handle named matches above:

  echo("Name: " .. matches.name .. "\n")
  echo("Class: " .. matches.class .. "\n")

Sending commands or printing information messages

To print information messages on the session screen you can use the echo( message ) function, or insertText( text ). Currently, it only takes one string as argument.

To send a command to the MUD, you can use the send( command ) function. In Alias scripts the command that is being sent to the MUD is contained in the variable command that you can change in the context of Alias scripts. Alias take regular expressions, as well. As a result, you can use following regex and script to talk like Yoda: Perl regex:

say (\w+).*(\w*).*(.*)

script:

send( "say " .. matches[4] .." " .. matches[2] .." ".. matches[3] )

Note: The variable "command" contains what was entered in the command line or issued via the expandAlias( ) function. If you use expandAlias( command ) inside an alias script the command would be doubled. You have to use send( ) inside an alias script to prevent recursion. This will send the data directly and bypass the alias expansion.

Changing and formatting text from the MUD

When sending commands to the MUD - from now on referred to as output stream - alias scripts find the command that was issued by the user stored in the variable "command".

By manipulating the value, the command can easily be changed before it is being sent to the MUD.

However, things get much more complicated with the data received from the MUD, from now on referred to as input stream. Before triggers can be run on the MUD data, Mudlet has to strip all format codes from the text and store it in data structures associated with the text. Consequently, the text that is being passed on to the trigger processing unit is a small subset of the data received from the MUD. If you want to edit, replace, delete or reformat text from within your trigger scripts you have to keep this in mind if you don’t want to lose all text format information such as colors etc.

As the text is linked with data structures containing the format of the text, the cursor position inside the line is important if data is being changed. You select a word or a sequence of characters from the line and then issue commands to do actions on the selected data.

Replacing the word "Tom" with "Betty" in the line: Jim, Tom and Lucy are learning a new spell. This could be done with following script:

selectString("Tom",1)
replace("Betty")

Things get more complicated if there are two or more occurrences of "Tom" in the line e.g. Jim and Tom like magic. Jim, Tom and Lucy are learning a new spell.

The above example code would select the first occurrence of "Tom" in this line and ignore the second. If you want to work on the the second occurrence of "Tom" you have to specify the occurrence number in the call to select().

selectString( "Tom", 2 )
replace( "Betty" )

This code would change the second "Tom" and leave the first "Tom" alone. The function call

replaceAll( "Betty" )

will replace all occurrences of "Tom" with "Betty" in the line if "Tom" has been selected before. replaceAll() is a convenience function defined in LuaGlobal.lua.

Colorization example: You want to change to color of the words "ugly monster" to red on a white background.

You add a new trigger and define the regex: ugly monster In the script you write:

selectString("ugly monster", 1 )
setFgColor(255,0,0)
setBgColor(255,255,255)
resetFormat()

Another means to select text is to select a range of characters by specifying cursor positions. If we have following line: Jim and Tom like magic. Jim, Tom and Lucy are learning a new spell.

selectSection( 28, 3 )

This example would select the second Tom. The first argument to selectSection is the cursor position within the line and the second argument is the length of the selection.

selectCaptureGroup( number )

This function selects the captureGroup number if you use Perl regular expressions containing capture groups. The first capture group starts with index 1.

Deleting Text - Gagging

deleteLine()

This function deletes the current line - or any line where the cursor is currently placed. You can use repeated calls to this function to effectively erase the entire text buffer. If you want to delete or gag certain words only, you can select the text that you want to delete and then replace it with an empty string e.g:

If you get this line form the MUD: "Mary and Tom walk to the diner."

selectString( "Tom", 1 )
replace( "" )

Then the output will be changed to: "Mary and walk to the diner."

Cursor Movement and Cursor Placement

Mudlet allows you to insert text arbitrarily within the buffer - in the previous line, in the previous ten lines, or even the first line that you've ever saw. These are the tools to help you with the job:

moveCursor( windowName, x, y ) This will move the user cursor of window windowName to the absolute (x/y) coordinates in the text.

moveCursor( "main", 20, 3950 ) will move the cursor on the 20th character from the left on line number 3950. To determine the current cursor position you can use getLineNumber() and getColumnNumber() as well as getLastLineNumber() to get the number of the last line in the text buffer. moveCursorEnd("main") will move the cursor of the main display to end of the buffer. This is always a new line of size 1 containing the character \n.

number_of_last_line_in_text = getLineCount() returns the number of the last line of the text in the console buffer. This number will change as soon as a new \n is printed either by the user or when a new line arrives from the MUD. All lines from the MUD are terminated with \n which is called line feed or the new line character. This control character ends the current line and move the cursor to the beginning of the next line, thus creating a new, empty line below the line that contains the \n.

line_number_of_the_current_cursor_position = getLineNumber()

column_number_of_the_current_cursor_position = getColumnNumber()

luaTable_containing_textlines = getLines( absolute_line_number_from, absolute_line_number_to ) this will return a Lua table containing all lines between the absolute positions from and to.

Note: This function uses absolute line numbers, not relative ones like in moveCursor().

moveCursor() returns true or false depending on whether the move was possible and done.

Inserting text in the middle of the line

Here's an example where we'll append the text (one) right after the word exit in the line of You see a single exit leading west.

The pattern we used was an exact match for You see a single exit leading west. and the code is:

if moveCursor(string.find(line, "exit")+#("exit")-1, getLineNumber()) then
  insertText("(one)")
end

What happened here:

• we triggered on the desired line using our pattern above
• we used moveCursor() to place the cursor in the desired position within the line. moveCursor() takes both the line number and the position within the line to place our virtual cursor on, so
  • we used string.find() to find the position of the word "exit" within the line
  • but string.find() returns us the position of the first character of the word we want, while we want to have the text be right after it - so we find out how long our word is with #("exit"), add that to the number returned by string.find() which gets us the first character + the length of the word - which isn't quite at the end of the word, but the word plus the space (because of string.find() and the first character) - so we substract 1 to move our cursor right at the end of the word
  • we then use getLineNumber() to get the current line number, so our cursor is placed on the current line, at our desired position
• lastly we finally insert the text with insertText(), which puts the text exactly where our virtual cursor is

Done! You can also use cinsertText() for coloured inserts, and other functions mentioned above and in the API manual to help you do what you'd like.

User defined dockable windows

You may want to use dock windows to display information you gathered in your scripts, or you may want to use them as chat windows etc. Check out Geyser.UserWindow on how to add them!

Dynamic Triggers

triggerID = tempTrigger( substring pattern, code ) creates a fast substring matching trigger

triggerID = tempRegexTrigger( regex, code ) creates a regular expression matching trigger

triggerID = tempBeginOfLineTrigger( begin of line pattern, code ) creates a fast begin of line substring trigger

Scripting howtos

How to convert a string to value?

Say you'd like to capture a number from a trigger, but the capture always ends up being a "string" (or, just text on which you can't do any maths on) even if it's a number. To convert it to a number, you'd want to use the tonumber() function:

myage = tonumber(matches[2])

How to highlight my current target?

You can put the following script into your targetting alias:

if id then killTrigger(id) end
id = tempTrigger(target, function() selectString(target, 1) fg("gold") deselect() resetFormat() end)

Where target is your target variable. Note that you have to use the full name, capitalized. If you’d like the script to auto-capitalize for you, you can use this version:

target = target:title()
if id then killTrigger(id) end
id = tempTrigger(target, function() selectString(target, 1) fg("gold") deselect() resetFormat() end)

Note: Ensure you're on Mudlet 3.5.0+ so you can put function() in a tempTrigger().

How to format an echo to a miniConsole?

One of the ways you can create multi-line displays in a miniConsole with variable information is with string.format and the use of [[ ]] brackets for text, which allow for multiple line in text:

local WindowWidth, WindowHeight = getMainWindowSize();
createMiniConsole("sys",WindowWidth-650,0,650,300)

local name, age, sex = "Bob", 34, "male"

cecho("sys", string.format([[

  /---------\
      %s
   %dyrs
   sex - %s 
  \---------/
]], name, age, sex))

How to play a sound when I receive communication while afk?

For this to work, place the line you'd like to trigger on in the first pattern box and select the appropriate pattern type. Then add return not hasFocus() with the Lua function as the second pattern, enable the AND trigger, and set the line delta to zero. Then just enable play sound, choose your sound and you're set!

How can I make a key that toggles between commands?

To make a key that toggles between two actions, for example - sleep/wake, you can use this as the script:

if not sleeping then
  send("sleep")
  sleeping = true
else
  send("wake")
  sleeping = false
end

How can I make a trigger with a next-line condition?

Here's how you can set it up - replace line1 and line2 with appropriate lines.

Here's the Mudlet XML you can download for this!

How to target self or something else?

Using regex and an 'or' statement allows us to consolidate multiple aliases, or an if statement, into a single more simple alias. When a regex is found it will use it, but if you don't specify one then the alternative will be used. The use of 'or' can be used with any function in Mudlet. In this example, one can type "buff" to buff themself, or "buff ally" to buff their ally instead.

^buff(?: (\w+))?$

send("cast buff on "..(matches[2] or "myself"))

How to delete everything between two lines?

When deleteLine() is called, every following line shifts back in numerical position. Thus if we know where we're starting and how many lines to expect, we can use a for loop to gag everything between line a and b by leaving the cursor in one spot. In the below example, line_a_number is the number of the line you want to start at, and line_b_number is the ending line. To gag x number of lines instead, use line_a_number + x in place of line_b_number.

for i = line_a_number, line_b_number, 1
do
   moveCursor(0, line_a_number)
   selectCurrentLine()
   deleteLine()
end

How to capture foreground line color information?

Here's an example that loops through each character in a line of text and prints the character and its foreground color to a miniconsole if the color has changed from the previous character:

Trigger: ^ (regex)

Code:

miniconsoleContainer =
  miniconsoleContainer or Adjustable.Container:new({name = "miniconsoleContainer"})
myMiniconsole =
  Geyser.MiniConsole:new(
    {
      name = "myMiniconsole",
      x = 0,
      y = 0,
      autoWrap = true,
      color = "black",
      scrollBar = false,
      fontSize = 8,
      width = "100%",
      height = "100%",
    },
    miniconsoleContainer
  )

local index = 0
local line = getCurrentLine()
local linesize = #line
local currentlinenumber = getLineNumber()
local r, g, b = 0, 0, 0
local cr, cg, cb -- last seen colors
while index < linesize do
  index = index + 1
  moveCursor("main", index, currentlinenumber)
  selectString(line:sub(index), 1)
  r, g, b = getFgColor()
  if cr ~= r or cg ~= g or cb ~= b then
    cr, cg, cb = r, g, b
    myMiniconsole:echo(string.format("rgb(%d,%d,%d)%s", r, g, b, line:sub(index, index)))
  else
    myMiniconsole:echo(string.format("%s", line:sub(index, index)))
  end
  line:sub(index, index)
end
myMiniconsole:echo("\n")

How to enter a carriage return / enter command?

Say you'd like to gag the following line, and just continue ...

[ Press Enter to continue ]

Trigger: [ Press Enter to continue ]  (set to exact match)
Code: deleteLine()
      send("\n")

How to repeat commands with #?

Install the following alias, and with it #5 mycommand will get repeated five times.

How to move the command line over?

See the first example in the setCmdLineStyleSheet function. Read the note attached to the function description.

How to add a background for Mudlets buttons?

You can give Mudlets buttons a background to have them blend in with your UI by doing this:

-- replace the /home/vadi/Pictures/tile.png location below with the one of your picture!
-- you can download the sample tile.png from https://opengameart.org/content/bevouliin-free-game-background-for-game-developers
local backgroundpath = [[/home/vadi/Pictures/tile.png]]
-- Windows:
-- local backgroundpath = [[C:/Users/Vadim/Downloads/Free game background/transparent PNG/tile.png]]

setAppStyleSheet([[
QToolBar {
  border-image: url(]]..backgroundpath..[[);

}

QToolBar QToolButton:!hover {
  color: white;
}
QToolBar QToolButton:hover {
  color: black;
}
]])

Result:

Advanced scripting tips

Do stuff after all triggers/aliases/scripts are run

This little snippet will have your commands be executed right after, depending on the context you run it in, all triggers, aliases or scripts are completed:

tempTimer(0, [[mycode]])

How to delete the previous and current lines

This little snippet comes from Iocun:

moveCursor(0,getLineCount()-1)
deleteLine()
moveCursor(0,getLineCount())
deleteLine()

db: Mudlet's database frontend

The DB package is meant to provide easier access to a database, so you don’t have to know SQL or use the luasql module to set and get at your data. However, it does require that the luasql module be compiled and included in Mudlet to function.

Creating a Database

Before you can store anything in a database, you need to create one. You may have as many independent databases as you wish, with each having as many unique tables-- what we will call sheets in this package, so as to avoid confusion with Lua tables - think spreadsheets.

To create a database, you use the db:create() function, passing it the name of your database and a Lua table containing its schema configuration. A schema is a mold for your database - it defines what goes where. Using the spreadsheet example, this would mean that you’d define what goes into each column. A simple example:

db:create("people", {friends={"name", "city", "notes"}, enemies={"name", "city", "notes"}})

This will create a database which contains two sheets: one named friends, the other named enemies. Each has three columns, name, city and notes-- and the datatype of each are strings, though the types are very flexible and can be changed basically whenever you would like. It’ll be stored in a file named Database_people.db in your Mudlet config directory on the hard drive should you want to share it.

It’s okay to run this function repeatedly, or to place it at the top-level of a script so that it gets run each time the script is saved: the DB package will not wipe out or clear the existing data in this case.

Note: You may not create a column or field name which begins with an underscore. This is strictly reserved to the db package for special use.

Note: Adding new columns to an existing database did not work in Mudlet 2.1 - see db:create() on how to deal with this.

Adding Data

To add data to your database, you must first obtain a reference (variable) for it. You do that with the db:get_database function, such as:

  local mydb = db:get_database("people")

The database object contains certain convenience functions (discussed later, but all are preceded with an underscore), but also a reference to every sheet that currently exists within the database. You then use the db:add() function to add data to the specified sheet.

  db:add(mydb.friends, {name="Ixokai", city="Magnagora"})

If you would like to add multiple rows at once to the same table, you can do that by just passing in multiple tables:

  db:add(mydb.friends,
    {name="Ixokai", city="Magnagora"},
    {name="Vadi", city="New Celest"},
    {name="Heiko", city="Hallifax", notes="The Boss"}
  )

Notice that by default, all columns of every table are considered optional-- if you don’t include it in the add, then it will be set to its default value (which is nil by default)

For those familiar with databases: with the DB package, you don’t have to worry about committing or rolling back any changes, it will commit after each action automatically. If you would like more control than this, see Transactions below.

You also cannot control what is the primary key of any sheets managed with DB, nor do you have to create one. Each row will get a unique integer ID that automatically increments, and this field can be accessed as "_row_id".

Querying

Putting data in isn’t any fun if you can’t get it out. If you want every row from the sheet, you can do:

  db:fetch(mydb.friends)

But rarely is that actually useful; usually you want to get only select data. For example, you only want to get people from the city of Magnagora. To do that you need to specify what criteria the system should use to determine what to return to you. It looks like this:

  db:fetch(mydb.friends, db:eq(mydb.friends.city, "Magnagora"))

So the basic command is - db:fetch(_sheet_, _what to filter by_)

The following filter operations are defined:

  db:eq(field, value[, case_insensitive]) -- Defaults to case insensitive, pass true as the last arg to
              reverse this behavior.
  db:not_eq(field, value[, case_insensitive) -- Not Equal To
  db:lt(field, value) -- Less Than
  db:lte(field, value) -- Less Than or  Equal to.
  db:gt(field, value) -- Greater Than
  db:gte(field, value) -- Greater Than or Equal To
  db:is_nil(field) -- If the column is nil
  db:is_not_nil(field) -- If the column is not nil
  db:like(field, pattern) -- A simple matching pattern. An underscore matches any single character,
          and a percent(%) matches zero or more characters. Case insensitive.
  db:not_like(field, pattern) -- As above, except it'll give you everything but what you ask for.
  db:between(field, lower_bound, upper_bound) -- Tests if the field is between the given bounds (numbers only).
  db:not_between(field, lower_bound, upper_bound) -- As above, only... not.
  db:in_(field, table) -- Tests if the field is in the values of the table. NOTE the trailing underscore!
  db:not_in(field, table) -- Tests if the field is NOT in the values of the table *

The db:in_ operator takes a little more explanation. Given a table, it tests if any of the values in the table are in the sheet. For example:

  db:in_(mydb.friends.city, {"Magnagora", "New Celest"})

It tests if city == "Magnagora" OR city == "New Celest", but with a more concise syntax for longer lists of items.

There are also two logical operators:

  db:AND(operation1, ..., operationN)
  db:OR(operation1, operation2)

You may pass multiple operations to db:fetch in a table array, and they will be joined together with an AND by default. For example:

  db:fetch(mydb.friends,
    {db:eq(mydb.friends.city, "Magnagora"), db:like(mydb.friends.name, "X%")}
  )

This will return every record in the sheet which is in the city of Magnagora, and has a name that starts with an X. Again note that in LIKE patterns, a percent is zero or more characters — this is the same effect as "X.*" in pcre patterns. Similarly, an underscore matches any single characters and so is the same as a dot in pcre.

Passing multiple expressions in an array to db:fetch is just a convenience, as its exactly the same as:

  db:fetch(mydb.friends, db:AND(db:eq(mydb.friends.city, "Magnagora"), db:like(mydb.friends.name, "I%")))

The db:OR operation only takes two arguments, and will check to see if either of the two is true. You can nest these logical operators as deeply as you need to.

You can also just pass in a string directly to db:fetch, but you have to be very careful as this will be passed straight to the SQL layer. If you don’t know any SQL then you want to avoid this… for example, in SQL there’s a very big difference between double and single quotes. If you don’t know that, then stick to the db functions. But an example is:

  db:fetch(mydb.friends, "city == 'Magnagora'")

Now, the return value of db:fetch() is always a table array that contains a table dictionary representing the full contents of all matching rows in the sheet. These are standard Lua tables, and you can perform all normal Lua operations on them. For example, to find out how many total items are contained in your results, you can simply do #results. If a request from the friends sheet were to return one row that you stored in the results variable, it would look like this if passed into the display() function:

  table {
  1: table {
    'name': 'Bob',
    'city': 'Magnagora',
    'notes': 'Trademaster of Tailoring'
  }
}

And if you were to echo(#results), it would show 1.

The order of the returned rows from db:fetch is generally the same as the order in which you entered them into the database, but no actual guarantees are made to this. If you care about the order then you can pass one or two optional parameters after the query to db:fetch() to control this.

The first table is an array of fields that indicate the column names to sort by; the second is a flag to switch from the default ascending(smallest to largest) sort, to a descending(largest to smallest) sort. For example:

  db:fetch(mydb.friends, db:eq(mydb.friends.city, "Magnagora"), {mydb.friends.city})

This will return all your friends in Magnagora, sorted by their name, from smallest to largest. To reverse this, you would simply do:

  db:fetch(mydb.friends, db:eq(mydb.friends.city, "Magnagora"), {mydb.friends.city}, true)

Including more then one field in the array will indicate that in the case that two rows have the same value, the second field should be used to sort them.

If you would like to return ALL rows from a sheet, but still sort them, you can do that by passing nil into the query portion. For example:

  db:fetch(mydb.friends, nil, {mydb.friends.city, mydb.friends.name})

This will return every friend you have, sorted first by city and then their name.

Indexes and Types

The sheets we’ve defined thus far are very simple, but you can take more control over the process if you need to. For example, you may assign default values and types to columns, and the DB package will attempt to coerce them as appropriate. To do that, you change your db:create() call as:

db:create("people", {
  friends={"name", "city", "notes"},
  enemies={
    name="",
    city="",
    notes="",
    enemied="",
    kills=0
  }
})

This is almost the same as the original definition, but we’ve defined that our first four fields are strings with a default value of blank, and the new kills field which is an integer that starts off at 0. The only way to set a datatype is to set a default value at this time.

Please note, beneath the DB package is SQLite, and SQLite is very data-type neutral. It doesn’t really care very much if you break those rules and put an integer in a string field or vice-versa, but the DB package will — to a limited degree — attempt to convert as appropriate, especially for the operations that work on numbers.

You may also create both standard and unique indexes. A unique index enforces that a certain criteria can only happen once in the sheet. Now, before you go and make indexes, pause and consider. There is no right or wrong answer when it comes to what to index: it depends on what kind of queries you do regularly. If in doubt, don’t make an index. Indexes will speed up reading data from the sheet, but they will slow down writing data.

To add an index, pass either the _index or _unique keys in the table definition. An example:

db:create("people", {
  friends={"name", "city", "notes"},
  enemies={
    name="",
    city="",
    notes="",
    enemied="",
    kills=0,
    _index = { "city" },
    _unique = { "name" }
  }
})

Now, bear in mind: _index = { "name", "city"} creates two indexes in this sheet. One on the city field, one on the name field. But, _index = { {"name", "city"} } creates one index: on the combination of the two. Compound indexes help speed up queries which frequently scan two fields together, but don’t help if you scan one or the other.

The admonition against making indexes willy-nilly holds double for compound indexes: do it only if you really need to!

Uniqueness

As was specified, the _unique key can be used to create a unique index. This will make it so a table can only have one record which fulfills that index. If you use an index such as _unique = { "name" } then names must be unique in the sheet. You can specify more than one key to be unique; in that case they will be checked in an OR condition.

Now, if you use db:add() to insert a record which would violate the unique constraint, a hard error will be thrown which will stop your script. Sometimes that level of protection is too much, and in that case you can specify how the db layer handles violations.

There are three possible ways in which the layer can handle such violations; the default is to FAIL and error out.

You can also specify that the db layer should IGNORE any commands that would cause the unique constraint to be violated, or the new data should REPLACE the existing row.

For example:

db:add(mydb.enemies, {name="Bob", city="Sacramento"})
db:add(mydb.enemies, {name="Bob", city="San Francisco"})

With the name field being declared to be unique, these two commands can’t succeed normally. The first db:add() will create a record with the name of Bob, and the second would cause the uniqueness of the name field to be violated. With the default behavior (FAIL), the second db:add() call will raise an error and halt the script.

If you want the IGNORE behavior, the second command will not cause any errors and it will simply fail silently. Bob’s city will still be Sacramento.

With the REPLACE behavior, the second command will cause its data to completely overwrite and replace the first record. Bob’s city will now be San Francisco.

A word of caution with REPLACE, given:

db:add(mydb.enemies, {name="Bob", city="Sacramento", notes="This is something."})
db:add(mydb.enemies, {name="Bob", city="San Francisco"})

With the REPLACE behavior, the second record will overwrite the first-- but the second record does not have the notes field set. So Bob will now not have any notes. It doesn’t -just- replace existing fields with new ones, it replaces the entire record.

To specify which behavior the db layer should use, add a _violations key to the table definition:

db:create("people", {
  friends={"name", "city", "notes"},
  enemies={
    name="",
    city="",
    notes="",
    enemied="",
    kills=0,
    _index = { "city" },
    _unique = { "name" },
    _violations = "IGNORE"
  }
})

Note that the _violations behavior is sheet-specific.

Timestamps

In addition to strings and floats, the db module also has basic support for timestamps. In the database itself this is recorded as an integer (seconds since 1970) called an epoch, but you can easily convert them to strings for display, or even time tables to use with Lua’s built-in time support.

The most common use for the Timestamp type is where you want the database to automatically record the current time whenever you insert a new row into a sheet. The following example illustrates that:

local mydb = db:create("combat_log",
  {
    kills = {
      name = "",
      area = "",
      killed = db:Timestamp("CURRENT_TIMESTAMP"),
      _index = { {"name", "killed"} }
    }
  }
)

-- observe that we don't provide the killed field here - DB automatically fills it in for us.
db:add(mydb.kills, {name="Drow", area="Undervault"})

results = db:fetch(mydb.kills)
display(results)

The result of that final display would show you this on a newly created sheet:

table {
  1: table {
    '_row_id': 1
    'area': 'Undervault'
    'name': 'Drow'
    'killed': table {
      '_timestamp': 1264317670
    }
  }
}

As you can see from this output, the killed fields contains a timestamp-- and that timestamp is stored as an epoch value in the GMT timezone. For your convenience, the db.Timestamp type offers three functions to get the value of the timestamp in easy formats. They are as_string, as_number and as_table, and are called on the timestamp value itself.

The as_number function returns the epoch number, and the as_table function returns a time table. The as_string function returns a string representation of the timestamp, with a default format of "%m-%d-%Y %H:%M:%S". You can override this format to anything you would like. Details of what you can do with epoch values, time tables, and what format codes you can use are specified in the Lua manual at: http://www.lua.org/pil/22.1.html for the Lua date/time functions.

A quick example of the usage of these functions is:

results = db:fetch(mydb.kills)
for _, row in ipairs(results) do
  echo("You killed " .. row.name .. " at: " .. (row.killed and row.killed:as_string() or "no time") .."\n")
end

Deleting

The db:delete function is used to delete rows from the sheet. It takes two arguments, the first being the sheet you are deleting and the second a query string built using the same functions used to build db:fetch() queries.

For example, to delete all your enemies in the city of Magnagora, you would do:

db:delete(mydb.enemies, db:eq(mydb.enemies.city, "Magnagora"))

Be careful in writing these! You may inadvertantly wipe out huge chunks of your sheets if you don’t have the query parameters set just to what you need them to be. Its advised that you first run a db:fetch() with those parameters to test out the results they return.

As a convenience, you may also pass in a result table that was previously retrieved via db:fetch and it will delete only that record from the table. For example, the following will get all of the enemies in Magnagora, and then delete the first one:

results = db:fetch(mydb.enemies, db:eq(mydb.enemies.city, "Magnagora"))
db:delete(mydb.enemies, db:eq(mydb.enemies._row_id, results[1]._row_id))

That is equivalent to:

db:delete(mydb.enemies, results[1])

You can even pass a number directly to db:delete if you know what _row_id you want to purge.

A final note of caution: if you want to delete all the records in a sheet, you can do so by only passing in the table reference. To try to protect you from doing this inadvertently, you must also pass true as the query after:

db:delete(mydb.enemies, true)

Updating

If you make a change to a table that you have received via db:fetch(), you can save those changes back to the database by doing:

db:update(mydb.enemies, results[1])

A more powerful (and somewhat dangerous, be careful!) function to make changes to the database is db:set, which is capable of making sweeping changes to a column in every row of a sheet. Beware, if you have previously obtained a table from db:fetch, that table will NOT represent this change.

The db:set() function takes two arguments: the field to change, the value to set it to, and the db:fetch() like query to indicate which rows should be affected. If you pass true as the last argument, ALL rows will be changed.

To clear out the notes of all of our friends in Magnagora, we could do:

db:set(mydb.friends.notes, "", db:eq(mydb.friends.notes, "Magnagora"))

Be careful in writing these!

Transactions

As was specified earlier, by default the db module commits everything immediately whenever you make a change. For power-users, if you would like to control transactions yourself, the following functions are provided on your database instance:

local mydb = db:get_database("my_database")
mydb:_begin()
mydb:_commit()
mydb:_rollback()
mydb:_end()

Once you issue a mydb._begin() command, autocommit mode will be turned off and stay off until you do a mydb._end(). Thus, if you want to always use transactions explicitly, just put a mydb._begin() right after your db:create() and that database will always be in manual commit mode.

Viewing and editing the database contents

A good tool to view and edit the database contents in raw form is SQlite Sorcerer (free and available for Linux, Windows, Mac).

Debugging raw queries

If you'd like to see the queries that db: is running for you, you can enable debug mode with db.debug_sql = true.

Discord Messages

Can you send messages from Mudlet to Discord? Totally. Here is an example:

function sendToDiscord(data)
  local url = "https://discord.com/api/webhooks/1204151397977821184/Cu8ZQQo9R11AyIt3DxpOEeB8MtVMA6_AEfXoZaYxqEAOu_6hwhtA2cRLIw-VIs7py7p8"
  local headers = {["Content-Type"] = "application/json"}
  local json = yajl.to_string(data)
  postHTTP(json, url, headers)
end

local data = {
  content = "Hello, Discord!",
  embeds = {
    {
      title = "This is an embed",
      url = "https://example.com",
      image = {
        url = "https://example.com/image.jpg"
      }
    }
  }
}

sendToDiscord(data)

Sure enough, after starting this script, you can see a message in Discord:

What you just need to do is create a webhook in a channel. Go to channel settings, then create this:

Here you can find more documentation on which fields Discord allows: https://discord.com/developers/docs/resources/webhook#execute-webhook

All this is one way though. Mudlet won't listen to messages from Discord. For that you'd probably have to make a Discord bot first.

Discord Rich Presence

Discord Rich Presence in Mudlet allows you, the player, to show off the game you're playing and you, the game author, to get your game shown off! Advertise your game for free alongside AAA titles in server player lists :)

To respect the players privacy, this option is disabled by default - enable it by ticking the Discord option for the profile:

Once enabled, a Discord-capable game will show information in your Discord!

To fine-tune the information you'd like to see displayed, go to Settings, Chat tab:

Implementing

As a game author, you have two ways of adding Discord support to your game: via GMCP (easy) or via Lua.

Adding support via GMCP means that your players don't have to install any Lua scripts which is a nicer experience. To do so, implement the Discord over GMCP specification and get in touch to let us know your game implements GMCP.

GMCP

Here's a quick cheatsheet to implement the GMCP spec:

1. Create a discord application
2. Upload game logo for "rich presence invite image"
3. Upload same game logo in "Rich Presence Assets" with the name of server-icon
4. Upon receiving "External.Discord.Hello" from the game client, reply with "External.Discord.Info" with applicationid (see screenshot) and "External.Discord.Status"
5. Send "External.Discord.Status" whenever you need to send data to the client, and fill it with the values have changed since the last status. Discord has some ideas for filling it in.
6. Done. Mudlet will enable the Discord checkbox upon receiving the applicationid from the game at least once.

Lua

An alternative way to add Discord support as a game author is via Lua - all of Discords functionality can be manipulated from it. Create a discord application and set it with setDiscordApplicationID(), then set the set the rest of the options as necessary:

Credit: Discord

If you're a game player and your game doesn't support Discord, you can still use the functionality to set the detail, status, party and time information as desired.

Available in Mudlet3.14+

MUD Client Media Protocol

Client.Media

Want to add accessibility and excitement into your game? How about implementing sound and music via GMCP?

The Client.Media family of GMCP packages provide a way for games to send sound and music events. GMCP media events are sent in one direction: from game server to to game client.

Client.Media in Mudlet

Media files may be downloaded manually or automatically if certain conditions are met.

Available in Mudlet4.4+

Mudlet accepts case-insensitive GMCP for the Client.Media namespace (for example, these are all acceptable: "Client.Media.Play", "client.media.play", "cLiEnT.MeDiA.Play").

Enabling Media

When a new profile opens, Mudlet adds to the Core.Supports.Set GMCP package "Client.Media 1" to signal to servers that it supports processing media files via GMCP:

Core.Supports.Set ["Client.Media 1", ...]

To process Client.Media GMCP data in Mudlet, these boxes in the Settings window of Mudlet must be checked:

1. The "Enable GMCP" box in the Miscellaneous section.
2. The "Allow server to download and play media" box in the Game protocols section.

These boxes are checked by default upon the start of a new profile in Mudlet.

Storing Media

Mudlet plays files cached in the "media" folder within a game's profile. To get files into the "media" folder you could perform either of these options:

1. Copy media files or extract them from an archive (zip)
2. Automatically download them from external resources such as your game's web server on the Internet.

To enable the second option (Internet), use the "url" parameter made available in the "Client.Media.Default", "Client.Media.Load" and "Client.Media.Play" GMCP packages described below.

Loading Media

Send a Client.Media.Default GMCP event to setup the default URL directory to load sound or music files from external resources. This would typically be done once upon player login.

Required	Key	Value	Purpose
Yes	"url"	<url>	Resource location where the media file may be downloaded.

For example, to setup the default URL directory for your game:

Client.Media.Default {
  "url": "https://www.example.com/sounds/"
}

If downloading from external resources, it is recommended to use Client.Media.Default, set this default URL directory once, and let Mudlet download all of your media files automatically from this one resource location. Otherwise, explicitly set the "url" parameter on all of your Client.Media.Load GMCP and Client.Media.Play GMCP events to ensure that files are downloaded from the intended location(s).

Send Client.Media.Load GMCP events to load sound or music files. This could be done when the player logs into your game or at the beginning of a zone that will need the media.

Required	Key	Value	Purpose
Yes	"name"	<file name>	Name of the media file. May contain directory information (i.e. weather/lightning.wav).
Maybe	"url"	<url>	Resource location where the media file may be downloaded. Only required if a url was not set above with Client.Media.Default.

For example, download the sound of a sword swooshing within the "media" folder:

Client.Media.Load {
  "name": "sword1.wav",
  "url": "https://www.example.com/sounds/"
}

Playing Media

Send Client.Media.Play GMCP events to play sound or music files.

Required	Key	Value	Default	Purpose
Yes	"name"	<file name>		Name of the media file. May contain directory information (i.e. weather/lightning.wav). Wildcards * and ? may be used within the name to randomize media files selection.
Maybe	"url"	<url>		Resource location where the media file may be downloaded. Only required if the file is to be downloaded remotely and a url was not set above with Client.Media.Default or Client.Media.Load.
No	"type"	"sound" or "music"	"sound"	Identifies the type of media.
No	"tag"	<tag>		Helps categorize media.
No	"volume"	1 to 100	50	Relative to the volume set on the player's client.
No	"fadein"	<msec>		Volume increases, or fades in, ranged across a linear pattern from one to the volume set with the "volume" key. Start position: Start of media. End position: Start of media plus the number of milliseconds (msec) specified. 1000 milliseconds = 1 second.
No	"fadeout"	<msec>		Volume decreases, or fades out, ranged across a linear pattern from the volume set with the "volume" key to one. Start position: End of the media minus the number of milliseconds (msec) specified. End position: End of the media. 1000 milliseconds = 1 second.
No	"start"	<msec>	0	Begin play at the specified position in milliseconds. 1000 milliseconds = 1 second.
No	"finish"	<msec>	0	End play at the specified position in milliseconds. 1000 milliseconds = 1 second.
No	"loops"	-1, or >= 1	1	Number of iterations that the media plays. A value of -1 allows the sound or music to loop indefinitely.
No	"priority"	1 to 100		Halts the play of current or future played media files with a lower priority while this media plays.
No	"continue"	true or false	true	Only valid for media files with a "type" of "music". Continues playing matching new music files when true. Restarts matching new music files when false.
No	"key"	<key>		Uniquely identifies media files with a "key" that is bound to their "name" or "url". Halts the play of current media files with the same "key" that have a different "name" or "url" while this media plays.

name

For example, to simply play the sound of a cow mooing already stored in the "media" folder:

Client.Media.Play {
  "name": "cow.wav"
}

Or some lightning stored in a "weather" sub-folder under the "media" folder.

Client.Media.Play {
  "name": "weather/lightning.wav"
}

The "name" parameter may be used for stopping media with the Client.Media.Stop GMCP event.

url

If you maintain your sound files on the Internet and don't set a default URL with Client.Media.Default, or preload them with Client.Media.Load, include the "url" parameter:

Client.Media.Play {
  "name": "cow.wav",
  "url": "https://www.example.com/sounds/"
}

type: sound

Media files default to a "type" of "sound" when the "type" parameter is not specified, such as in the example above. It is good practice to specify the "type" parameter to best keep media organized within your implementation:

Client.Media.Play {
  "name": "cow.wav",
  "type": "sound"
}

The "type" parameter may be used for stopping matching media with the Client.Media.Stop GMCP event.

tag

To play the sound of a sword swooshing and categorized as "combat":

Client.Media.Play {
  "name": "sword1.wav",
  "type": "sound",
  "tag": "combat"
}

The "tag" parameter may be used for stopping matching media with the Client.Media.Stop GMCP event.

type: music

Add background music to your environment through use of the "music" value set upon the "type" parameter:

Client.Media.Play {
  "name": "river.wav",
  "type": "music",
  "tag": "environment"
}

The "type" parameter may be used for stopping matching media with the Client.Media.Stop GMCP event.

volume: 1 to 100

As the character draws nearer to or farther from the environmental feature, consider adjusting the "volume" parameter. Example values, followed by syntax examples:

• Maximum: 100 (recommended to use rarely)
• High: 75
• Default: 50
• Low: 25
• Minimum: 1 (recommended to use rarely)

Client.Media.Play {
  "name": "river.wav",
  "type": "music",
  "tag": "environment",
  "volume": 75
}

Although using the integer type is recommended, Mudlet parses "volume" values of type string ("75") into integers (75) as needed.

fadein

Increase volume from the start of the media [start position, volume one] to the number in milliseconds specified with the "fadein" parameter [position start + milliseconds, volume specified with the "volume" parameter]. Example values, followed by syntax examples:

• 1000 milliseconds (1 second)
• 60000 milliseconds (1 minute)
• 0 milliseconds (no fade in)

Client.Media.Play {
  "name": "monty_python.mp3",
  "type": "music",
  "volume": 100,
  "fadein": 1000
}

        +---------------------------+-----------------------+
        | Fade in 1000 milliseconds |         Normal        |
        +---------------------------+-----------------------+
Volume 1|........::::::::::iiiiiiiii%%%%%%%%%%%%%%%%%%%%%%%%|Volume 100
        +---------------------------+-----------------------+

Although using the integer type is recommended, Mudlet parses "fadein" values of type string ("1000") into integers (1000) as needed.

fadeout

Decrease volume from a position in milliseconds subtracted from the duration of the media [position duration - milliseconds, volume specified with the "volume" parameter] to the end of the media [position duration, volume one]. Example values, followed by syntax examples:

• 1000 milliseconds (1 second)
• 60000 milliseconds (1 minute)
• 0 milliseconds (no fade out)

Client.Media.Play {
  "name": "the_matrix.mp3",
  "type": "music",
  "volume": 50,
  "fadeout": 333
}

         +-----------------------+---------------------------+
         |        Normal         | Fade out 333 milliseconds |
         +-----------------------+---------------------------+
Volume 50|%%%%%%%%%%%%%%%%%%%%%%%%iiiiiiiii::::::::::........|Volume 1
         +-----------------------+---------------------------+

Although using the integer type is recommended, Mudlet parses "fadeout" values of type string ("333") into integers (333) as needed.

start

Start playing a media track at the number of milliseconds specified. Example values, followed by syntax examples:

• 1000 milliseconds (1 second)
• 60000 milliseconds (1 minute)
• 0 milliseconds (start from beginning)

Client.Media.Play {
  "name": "mudlet_beatboxing.mp3",
  "type": "music",
  "volume": 75,
  "start": 1000
}

Although using the integer type is recommended, Mudlet parses "start" values of type string ("100") into integers (100) as needed.

finish

Finish playing a media track at the number of milliseconds specified. Example values, followed by syntax examples:

• 1000 milliseconds (1 second)
• 60000 milliseconds (1 minute)
• 0 milliseconds (start from beginning)

Client.Media.Play {
  "name": "mudlet_beatboxing.mp3",
  "type": "music",
  "volume": 75,
  "finish": 35000
}

Although using the integer type is recommended, Mudlet parses "finish" values of type string ("100") into integers (100) as needed.

loops: -1, 1 or more

The "loops" parameter controls how many times the sound repeats and defaults to 1 if not specified. A value of -1 will loop the file indefinitely.

Client.Media.Play {
  "name": "clock/hour_bell.wav",
  "type": "sound",
  "loops": 3
}

Client.Media.Play {
  "name": "underdark.mp3",
  "type": "music",
  "tag": "environment",
  "loops": -1
}

Although using the integer type is recommended, Mudlet parses "loops" values of type string ("-1") into integers (-1) as needed.

priority: 1 to 100

The "priority" parameter sets precedence for Client.Media.Play GMCP events that include a "priority" setting. The values for the "priority" parameter range between 1 and 100. Given that two Client.Media.Play GMCP events have the same priority, the media already playing will continue playing. In Mudlet, media without priority set is not included comparisons based on priority.

A common place to find priority implemented is with combat. In the following example, imagine a combat scenario where some sounds of sword thrusts were interrupted by a successful blocking maneuver.

Client.Media.Play {
  "name": "sword1.wav",
  "type": "sound",
  "tag": "combat",
  "loops": 3,
  "priority": 60
}

Client.Media.Play {
  "name": "block1.wav",
  "type": "sound",
  "tag": "combat",
  "priority": 70
}

Although using the integer type is recommended, Mudlet parses "priority" values of type string ("25") into integers (25) as needed.

The "priority" parameter may be used for stopping matching media with the Client.Media.Stop GMCP event.

continue: true or false (for music)

Typically sent with the "type" of "music" is the parameter "continue", which presents the following values:

• true: continues music that is already playing if it is requested again through a new Client.Media.Play GMCP event
• false: restarts music that is already playing if it is requested again through a new Client.Media.Play GMCP event

Client.Media.Play {
  "name": "city.mp3",
  "type": "music",
  "tag": "environment",
  "continue": true
}

If the "continue" parameter is not specified, behavior will default to true for music.

Although using the boolean type is recommended, Mudlet parses "continue" values of type string ("true" and "false") into boolean (true and false) as needed, as not all game drivers support a boolean type.

key

The "key" parameter enables media categorization, similar to the "tag" parameter, however it adds a feature of uniqueness that halts media currently playing with the same key, replacing it with the media that arrived from a new Client.Media.Play GMCP event. This update will only occur if the "name" or "url" associated with the currently playing media does not match the new media, while the key is identical.

In the example below, consider that a player moves from a sewer area to a village. The "key" parameter is used to stop the previously playing sewer.mp3 and start playing village.mp3 within the second Client.Media.Play GMCP event.

Client.Media.Play {
  "name": "sewer.mp3",
  "type": "music",
  "tag": "environment",
  "loops": -1,
  "continue": true,
  "key": "area-music"
}

Client.Media.Play {
  "name": "village.mp3",
  "type": "music",
  "tag": "environment",
  "loops": -1,
  "continue": true,
  "key": "area-music"
}

The "key" parameter may be used for stopping matching media with the Client.Media.Stop GMCP event.

Note: Where music is bound to change, continue or stop as a player enters a new room, consider allowing for a slight pause of 1 heart beat or tick to send the Client.Media.Play or Client.Media.Stop GMCP events. This practice reduces the number of Client.Media.Play GMCP events sent when the player travels through several rooms quickly.

randomization

Wildcards * (asterisk) and ? (question mark) may be used within the name to randomize media file(s) selection.

Given that media files underdark.wav, underdark.mp3 and underdark_dark_elven_moshpit.mp3 were all present in the media/environment directory under the current game profile, the following Client.Media.Play GMCP event would randomly choose one of those files to play using the * wildcard.

Client.Media.Play {
  "name": "underdark*",
  "type": "music",
  "tag": "environment",
  "loops": -1,
  "continue": false
}

If media files sword1.wav, sword2.wav and sword3.wav were all present in the media/combat directory under the current game profile, the following Client.Media.Play GMCP event would randomly choose one of those files to play per each loop using the ? wildcard.

Client.Media.Play {
  "name": "combat/sword?.wav",
  "type": "sound",
  "tag": "combat",
  "loops": 3
}

Stopping Media

Send Client.Media.Stop GMCP events to stop sound or music media.

Required	Key	Value	Purpose
No	"name"	<file name>	Stops playing media by name matching the value specified.
No	"type"	"sound" or "music"	Stops playing media by type matching the value specified.
No	"tag"	<tag>	Stops playing media by tag matching the value specified.
No	"priority"	1 to 100	Stops playing media with priority less than or equal to the value.
No	"key"	<key>	Stops playing media by key matching the value specified.
No	"fadeaway"	true or false	Decrease volume from the current position for a given duration, then stops the track. Given duration is the lesser of the remaining track duration or the fadeout specified in Client.Media.Play. If fadeout was not specified in Client.Media.Play, then the optional fadeout parameter from Client.Media.Stop or a default of 5000 milliseconds will be applied.
No	"fadeout"		Default duration in milliseconds to decrease volume to the end of the track. Only used if fadeout was not defined in Client.Media.Play.

all

Send the Client.Media.Stop GMCP event with no parameters to stop all playing media within a given game profile.

Client.Media.Stop {}

parameters

Send any combination of the name, type, tag, priority or sound parameters and valid corresponding values to stop playing media that matches all combinations of the parameters.

Stop the rain.

Client.Media.Stop {
  "name": "rain.wav"
}

Stop all media using the "type" of "sound".

Client.Media.Stop {
  "type": "sound"
}

Stop all media categorized with the "tag" of "combat" and that has a "priority" less than or equal to 50.

Client.Media.Stop {
  "tag": "combat",
  "priority": 50
}

Stop all media categorized with the "key" of "area-music".

Client.Media.Stop {
  "key": "area-music"
}

Decrease volume for 5 seconds (or the fadeout parameter defined in Client.Media.Play) and then stop all playing music files for this profile

Client.Media.Stop {
  "fadeaway": true
}

Decrease volume for 10 seconds all media categorized with the "key" of "area-music" and then stop the music

Client.Media.Stop {
  "key": "area-music",
  "fadeaway": true,
  "fadeout": 10000
}

GUI Scripting in Mudlet

Mudlet has extremely powerful GUI capabilities built into it, and with the inclusion of the Geyser and Vyzors layout managers in Mudlet's Lua API it is quicker and easier to get a basic UI created.

Geyser

Geyser is an object oriented framework for creating, updating and organizing GUI elements within Mudlet - it allows you to make your UI easier on Mudlet, and makes it easier for the UI to be compatible with different screen sizes.

Geyser's manual is quite extensive - follow here to read up on it.

UI template

Akaya has created a UI template based on Geyser that can serve as a quick start for customizing the Mudlet interface to your character:

To get started with it, see the forum thread about Geyser UI Template.

Simple Window Manager

Simple Window Manager is a light-weight script designed to provide the GUI object placement and sizing functionality seen in Geyser and Vyzor without any of the extras. Any GUI object, once created normally, can be added to the SWM along with a corner to base its positioning info off of, the distance from that corner, and the size of the object in any combination of pixels and percentages of the screen. SWM does all the behind the scenes work to keep all objects it has been given to manage in their correct places and sizes as the screen changes size. All other interactions with GUI objects are handled using standard functions built into Mudlet.

Simple Window Managers manual, and download, can be found here.

Useful Resources

There are several useful resources you can refer to when creating your GUI.

Wiki Resources

• Geyser Tutorial:

Excellent for getting an initial feel of how to use the Geyser layout manager.

• GUI API:

The GUI section of the Lua API manual

External Resources

• Geyser subforum:

The Geyser Layout Manager subforum on Mudlet's forums.

• GUI Screenshots:

A pinned thread on Mudlet's forums for showing what your GUI looks like. Useful for ideas and to see what is possible.

• Godwars II Mudlet UI:

A forum thread which follows the evolution of the UI provided by God Wars II

Resetting your UI

While scripting your UI, you can reset it completely and have your scripts be loaded from scratch with the resetProfile() function - in the input line, type lua resetProfile().

Timer Engine

Mudlet supports four different sorts of timers:

1. Regular GUI Timers
2. Temporary Timers
3. Offset Timers
4. Stopwatches

The first can be configured by clicking and will start some code in regular intervals. The others can be used in other scripts you code. All of them are described in more detail below.

Regular GUI Timers

Regular GUI Timers that fire repeatedly in a certain interval specified by the user. To make one, go to the Timers section (1) in Mudlet, click Add (2), select the time periods you'd like the timer to be going off at - save (3) and activate it (4). The timer will go off after your specified interval and then at regular specified intervals after that, until disabled.

You can also enable/disable this timer via scripting with enableTimer() and disableTimer():

enableTimer("Newbie timer") -- enables the timer, so 2s after being enabled, it'll tick - and every 2s after that

disableTimer("Newbie timer") -- disables it, so it won't go off anymore

Temporary Timers

Temporary Timers are timers that go off only once and are the most common type of timer used for scripting purposes. You don't work with them from the Timers section - you just code with them only.

For a basic introduction to temporary timers, read up about them here. Here, we'll continue expanding on what you've learnt so far.

One thing to keep in mind when working with tempTimers is that they are unlike #wait statements you might see in other clients. While #waits are typically cumulative, tempTimers aren't - they go off from the same point in time. Thus if you'd like two timers to go off - one after 3s, and another 1s after the first one - you'd set the second timer to go off at 4s. For example:

tempTimer(3, [[ echo("this is timer #1 going off 3s after being made\n") ]])
tempTimer(4, [[ echo("this is timer #2 going off 4s after being made - and 1s after the first one\n") ]])

Note: Temporary timers cannot be accessed from the GUI and are not saved in profiles.

Stopping

To stop a temporary timer once you've made it and before before it went off - you use killTimer(). You give killTimer(id) the ID of the timer that you've made - which you get from Mudlet when you make it. Here's an example:

-- get and store the timer ID in the global "greeting_timer_id" variable
greeting_timer_id = tempTimer(2, [[ echo("hello!\n") ]])

-- delete the timer - thus nothing will actually happen!
killTimer(greeting_timer_id)

Refreshing

You can also use killTimer() to "refresh" a timer - the following code example will delete the previous timer if one exists and create the new one, thus making sure you don't get multiple copies of it:

if portal_timer then killTimer(portal_timer) end
portal_timer = tempTimer(2, [[ send("enter portal") ]])

Time remaining

You can use remainingTime() to check how much time remains on a provided Timer.

tid = tempTimer(600, [[echo("\nYour ten minutes are up.\n")]])
echo("\nYou have " .. remainingTime(tid) .. " seconds left, use it wisely... \n")

-- Will produce something like:

You have 599.923 seconds left, use it wisely... 

-- Then ten minutes time later:

Your ten minutes are up.

Using variables

To embed a value of a variable in tempTimer code, you might try using this given what you've learnt:

tempTimer(1.4, [[ echo("hello, "..matches[2].."!\n") ]])

But that won't work as you'd expect it to - that will try and use the value of matches[2] when the timer goes off - while by then, the variable could have changed! Instead, you take it outside the square [[ ]] brackets - this is correct:

tempTimer(1.4, [[ echo("hello, ]]..matches[2]..[[!\n") ]])

-- or with less brackets:
tempTimer(1.4, function() echo("hello, "..matches[2].."!\n") end)

Nesting

If you'd like, you can also nest tempTimers one inside another - though the first [[]]'s will become [=[ ]=]:

tempTimer(1, [=[
  echo("this is timer #1 reporting, 1s after being made!\n")
  tempTimer(1, [[
    echo("this is timer #2 reporting, 1s after the first one and 2s after the start\n")
  ]])
]=])

If you'd like to nest more of them, you'd increase the amount of ='s on the outside:

tempTimer(1, [==[
  echo("this is timer #1 reporting, 1s after being made!\n")
  tempTimer(1, [=[
    echo("this is timer #2 reporting, 1s after the first one and 2s after the start\n")

    tempTimer(1, [[
      echo("this is timer #2 reporting, 1s after the second one, 2s after the first one, 3s after the start\n")
    ]])
  ]=])
]==])

Closures

Last but not least, you can also use closures with tempTimer - using a slightly different syntax that has advantages. For example, you have access variables in its scope, when it goes off:

local name = matches[2]
tempTimer(2.4, function() echo("hello, "..name.."!\n") end)

Also syntax highlighting will work as expected, because the function will not be given as a string.

Note: In this case, you mustn't use matches[2] directly in the echo() command. It will not work as expected. Instead, bind the it to a new variable like name as seen in the example above.

Offset Timers

Offset Timers are child timers of a parent timer and fire a single shot after a specified timeout after their parent fired its respective timeout. This interval is an offset to the interval of its parent timer. To make them, add a regular GUI timer (see above), then create another timer and drag it onto the timer. This will make the timer that is "inside" the timer (the child inside the parent) go off at a certain time after its parent goes off. Offset timers differ visually from regular timers and are represented with a + icon for offset. Offset timers can be turned on and off by the user just like any other timer. For example - a parent timer fires every 30 seconds and by doing so kicks off 3 offset timers with an offset of 5 seconds each. Consequently, the 3 children fire 5 seconds after each time the parent timer fired. To make this happen, make the parent timer tic every 30 seconds, drag 3 timers into it with an offset of 5s on each:

Uses and examples

Enable/disable triggers

This'll make use of tempTimer to enable a trigger and disable it after a short period of time:

enableTrigger("Get enemy list")
tempTimer(3, [[disableTrigger("Get enemy list")]])

Running a script after the current triggers

A useful trick to get your code to run right after all of the current triggers (GUI and temporary) ran would be to use a time of 0:

-- in a script, this will run after all scripts were loaded - including the system, wherever in the order it is.
tempTimer(0, function()
  print("this timer is running after all triggers have run")
end)

Have more examples you'd like to see? Please add or request them!

Stopwatches

The stopwatch feature can be used to time how long things take, e.g. long running functions or how long a fight lasts. Stopwatches can be started, stopped and reset just like a regular physical stopwatch. They can also be given a name and made to be persistent, meaning that they can keep running (or timing) when Mudlet has been closed. This gives you the ability to time real-life events. Of course, you can also query how much time has passed and delete a stopwatch no longer required.

Creating and Starting

fightStopWatch = fightStopWatch or createStopWatch() -- create, or re-use a stopwatch, and store the watch variable ID in a global variable to access it from anywhere

-- then you start the stopwatch in some trigger/alias/script with;
startStopWatch(fightStopWatch)

The watch will now be running. Alternatively, you can create and instantly start a stopwatch in one line;

fightStopWatch = fightStopWatch or createStopWatch(true)

See also: createStopWatch(), startStopWatch()

Stopping and Resetting

You can stop a stopwatch and retrieve its run time as follows;

-- in a trigger script for example you can write:
fightTime = stopStopWatch(fightStopWatch)
echo("The fight lasted for " .. fightTime .. " seconds.")

Then reset it for the next fight.

resetStopWatch(fightStopWatch)

Note that resetting a stopwatch does not stop or start it, it's simply resets the time value to zero.

See also: stopStopWatch(), resetStopWatch()

Deleting a Stopwatch

To delete a stopwatch and free up the variable ID simply;

deleteStopWatch(fightTime)

See also: deleteStopWatch()

More Ways to Retrieve Running Time

The time can be retrieved at any point of a started and currently running or stopped stopwatch.

• getStopWatchTime - returns the time as a decimal number of seconds with up to three decimal places to give a milli-seconds
• getStopWatches - returns a table of the details for each stopwatch in existence
• getStopWatchBrokenDownTime - returns a table of times for a given stopwatch; days, hours, minutes, etc...

See also: getStopWatchTime(), getStopWatches(), getStopWatchBrokenDownTime()

Using Named Stopwatches

All variable names can be replaced with a string name. Let's rewrite the above code with named stopwatches instead.

fightStopWatch = fightStopWatch or createStopWatch("Fight Stopwatch", true) -- using the name 'Fight Stopwatch' and starting it automatically

-- some time has passed

stopStopWatch("Fight Stopwatch")
echo("The fight lasted for " .. getStopWatchTime("Fight Stopwatch") .. " seconds.")
resetStopWatch("Fight Stopwatch")

Using Persistence

It is preferable (for technical reasons) to assign a name to a stopwatch that will persist over Mudlet sessions.

fightStopWatch = fightStopWatch or createStopWatch("Fight Stopwatch")
setStopWatchPersistence("Fight Stopwatch") -- enable this stopwatch to persist over Mudlet sessions
display(getStopWatches()) -- will now show that the stopwatch is persistent

See also: setStopWatchPersistence()