Manual:Advanced Lua - Revision history

Dt192 at 08:20, 16 February 2026

2026-02-16T08:20:11Z

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Zooka: /* Lua tables */ tables tutorial

2025-10-13T01:47:23Z

Lua tables: tables tutorial

Zooka: /* Lua tables */

2024-11-03T12:33:32Z

Lua tables

Zooka: /* Lua tables */

2024-11-03T12:28:05Z

Lua tables

Atari2600tim: /* Coroutines */

2024-10-25T20:55:36Z

Coroutines

Zooka: batch processing with coroutines

2024-05-15T06:47:53Z

batch processing with coroutines

TachyonicBytes: /* Regex in Lua */

2023-06-02T17:47:25Z

Regex in Lua

TachyonicBytes: /* Regex in Lua */

2023-06-01T22:55:47Z

Regex in Lua

TachyonicBytes: Split the regex section by function

2023-06-01T05:18:58Z

Split the regex section by function

TachyonicBytes: Added lrexlib documentation

2023-05-31T08:49:30Z

Added lrexlib documentation

← Older revision		Revision as of 01:47, 13 October 2025
Line 56:		Line 56:

	See also: [[Manual:Lua_Functions#Table_Functions\|Table Functions API]]		See also: [[Manual:Lua_Functions#Table_Functions\|Table Functions API]]
		+
		+	=== Example: Enemy Tracker Using Tables ===
		+
		+	Putting all the above together let's create a real-life example of a table that will hold a list of enemies, their level and the area we found them in. We also want this table to persist over sessions, so we will save and load the table. So we need a way to add to the table, remove from it, display a list of enemies, save and load.
		+
		+	First we initialise the table (called <code>enemies</code>) by creating an empty table, and if a save file exists populate the table with data.
		+
		+	<syntaxhighlight>
		+	-- a variable to hold the table location so we don't have to keep typing the whole line
		+	-- the file will be stored in your profile
		+	local enemiesFile = getMudletHomeDir() .. "/enemies.lua"
		+
		+	-- create the table if it doesn't already exist
		+	local enemies = enemies or {}
		+
		+	-- if the file exists then load it into the enemies table
		+	if io.exists(enemiesFile) then
		+	table.load(enemiesFile, enemies)
		+	end
		+	</syntaxhighlight>
		+
		+	Let's make a few functions to manipulate the table; add, show and save.
		+
		+	<syntaxhighlight>
		+	-- add data to the enemies table, it accepts name, level and area as arguments
		+	-- we could call this function from the command line, trigger, alias, etc..
		+	-- e.g., addEnemy("ogre", 15, "The Forest Path")
		+	function addEnemy(name, level, area)
		+	table.insert(enemies, { ['name'] = name, ['level'] = level, ['area'] = area})
		+	saveEnemies()
		+	end
		+
		+	-- print out the table to the screen
		+	function showEnemies()
		+	display(enemies)
		+	end
		+
		+	-- save the table for reloading next gaming session
		+	function saveEnemies()
		+	table.save(enemiesFile, enemies)
		+	end
		+	</syntaxhighlight>
		+
		+	Every time we add a new enemy the table also gets saved.
		+
		+	Let's add one more function to search the table by name of the enemy.
		+
		+	<syntaxhighlight>
		+	function getEnemyData(name)
		+	for k,v in pairs(enemies) do
		+	if v.name == name then
		+	return v
		+	end
		+	end
		+	end
		+	</syntaxhighlight>
		+
		+	Now we can retrieve data from the table
		+	e.g., <code>getEnemyData("ogre")</code> will return a small set of data (the name, level and area) from the enemies table.
		+
		+	If we specifically wanted the level, we could call it like so; <code>getEnemyData("ogre").level</code>
		+
		+	This ends the tutorial, but you can see how we can keep building and improving the functions for your specific goal. Other things you might add could be; deleting enemy entries, checking for duplicates (delete followed by add) or improving the show function for a neater look.

	== How to use multimatches[n][m] ==		== How to use multimatches[n][m] ==

@@ Line 54: / Line 54: @@
 -- the stats table now only contains hp, mana and moves
 </syntaxhighlight>
 == How to use multimatches[n][m] ==

@@ Line 6: / Line 6: @@
 == Lua tables ==
 A good overview of tables is available on Lua's wiki in the [http://lua-users.org/wiki/TablesTutorial TablesTutorial]. Nick Gammon has also written a nice [http://www.gammon.com.au/forum/bbshowpost.php?bbsubject_id=6036 overview on how to deal with Lua tables].
 == How to use multimatches[n][m] ==

@@ Line 304: / Line 304: @@
   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 <code>if mudlet.supportscoroutines then return end</code> bit. Older Mudlets that don't support coroutines might crash, which sucks. Newer ones that do support them are completely fine, however!
+Note that if you'll be using coroutines as part of a package you'll give to others, remember about the <code>if mudlet.supports.coroutines then return end</code> 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.

← Older revision		Revision as of 06:47, 15 May 2024
Line 307:		Line 307:

	Coroutines have many uses: finite state machines, running intensive tasks (yielding every once in a while so Mudlet isn't frozen), and so on.		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.
		+
		+	<syntaxhighlight lang="lua">
		+	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
		+	</syntaxhighlight>
		+
		+	All running <code>lua batch()</code> you will see;
		+
		+	<syntaxhighlight lang="lua">
		+	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.
		+
		+	...
		+	</syntaxhighlight>

	== Introspective facilities ==		== Introspective facilities ==

@@ Line 124: / Line 124: @@
 <syntaxhighlight lang="lua">
 > rex.match("The answer is 42", "(\\d+)")
 </syntaxhighlight>

← Older revision		Revision as of 22:55, 1 June 2023
Line 119:		Line 119:

	Keep in mind that precomputing a pattern with the ''new'' function has the advantage that objects resulted will be [http://rrthomas.github.io/lrexlib/manual.html#new garbage collected] and that regexes are greedy by default.		Keep in mind that precomputing a pattern with the ''new'' function has the advantage that objects resulted will be [http://rrthomas.github.io/lrexlib/manual.html#new garbage collected] and that regexes are greedy by default.
		+
		+	Another thing that may surprise some users is that, when escaping, you need to backslashes:
		+
		+	<syntaxhighlight lang="lua">
		+	> rex.match("The answer is 42", "(\\d+)")
		+	</syntaxhighlight>

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

@@ Line 117: / Line 117: @@
 If you set the flavor to ''rex_pcre'', your code should work afterwards in Mudlet.
 There are a few functions that you need to know: ''gsub'', ''count'', ''split'', ''find'', ''match''.
-=== Common behavior ===
+=== count ===
 The ''count'' function counts the matches:
@@ Line 137: / Line 139: @@
 </syntaxhighlight>
-Precomputing the pattern has the advantage that objects resulted will be [http://rrthomas.github.io/lrexlib/manual.html#new garbage collected].
+Remember that regexes are greedy by default:
 <syntaxhighlight lang="lua">
 > print(rex.count("aaa", ".*"))
 </syntaxhighlight>
 The ''split'' function splits a string according to a regex pattern:
@@ Line 171: / Line 173: @@
+a
 </syntaxhighlight>
 The ''find'' function searches for the first match, and returns the offsets where the match starts and ends.
@@ Line 196: / Line 200: @@
 	4
 </syntaxhighlight>
 The ''match'' function works similarly to the ''find'' function, but returns the matches instead of the indices:
@@ Line 211: / Line 217: @@
 def
 </syntaxhighlight>
 The ''gsub'' function replaces the pattern in the string, with the value in the third parameter:
@@ Line 233: / Line 241: @@
 The case insensitive flag:
 <syntaxhighlight lang="lua">
-> rex_pcre = require("rex_pcre")
+> rex = require("rex_pcre")
-> flags = rex_pcre.flags()
+> flags = rex.flags()
-> print(rex_pcre.find("ABab", "a", 0, flags.CASELESS))
+> print(rex.find("ABab", "a", 0, flags.CASELESS))
 	1
 </syntaxhighlight>

@@ Line 101: / Line 101: @@
 </syntaxhighlight>
-The lrexlib manual can be hard to read, so the instructions in this section should provide most of what you need.
+The ''lrexlib'' manual can be hard to read, so the instructions in this section should provide most of what you need.
-''lrexlib'' does not come preinstalled, so you will have to install it. 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.
+''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.
 <syntaxhighlight lang="bash">
@@ Line 115: / Line 115: @@
 > local rex = require("rex_posix")
 </syntaxhighlight>
 There are a few functions that you need to know: ''gsub'', ''count'', ''split'', ''find'', ''match''.
@@ Line 134: / Line 136: @@
 </syntaxhighlight>
 Regexes are greedy by default:
@@ Line 157: / Line 161: @@
 </syntaxhighlight>
-Be careful though, because the split does not consume all the characters with the same value, if they are adjacent:
+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:
 <syntaxhighlight lang="lua">