View source for Manual:Coding conventions/Lua

<languages/>
{{essay}}

<translate>
== Whitespace == <!--T:1-->
</translate>
# <translate><!--T:2--> Use tabs for indentation.</translate> <translate><!--T:3--> Previously we used 4 spaces, but we have now switched to tabs after the default behaviour of Wikipedia's code editor changed.</translate>
# <translate><!--T:4--> Try to limit the length of a single line, so people with smaller monitors can read the code easily.</translate>
# <translate><!--T:5--> Avoid extraneous whitespace when calling a function or subscripting an array or dictionary.</translate> <translate><!--T:6--> No spaces should be used immediately before or inside a bracketing character (<tvar name=1><code>[, (, {</code></tvar> and their matches).</translate>
<syntaxhighlight lang='lua'>
-- Yes:
hi = {1, 2, 3}
foo(hi[1], blah['a'])

-- No:
hi = { 1, 2, 3 }
foo( hi[ 1 ], blah[ 'a' ] )
blah ['b'] = hi [3]
foo (0, '')
</syntaxhighlight>

<translate>
== Control flow == <!--T:7-->
</translate>
<translate><!--T:8--> Putting multiple statements on one line is discouraged, unless the expression is very short.</translate>
<translate><!--T:9--> Try to avoid this with multi-clause statements, too.</translate>

<syntaxhighlight lang='lua'>
-- <translate nowrap><!--T:11--> Yes:</translate>
if 1 then
	foo()
	bar()
else
	baz()
end

if 1 then foo() end

foo(); bar(); baz();

-- <translate nowrap><!--T:12--> No:</translate>
if 1 then foo(); bar(); else baz(); end

if 1 then foo(); bar(); baz();
else lorem(); ipsum(); end

foo(); bar(); baz(); spam(); eggs(); lorem(); ipsum(); dolor(); sit(); amet();
</syntaxhighlight>

<translate><!--T:13--> If a single line would be too long, you can split a large statement over multiple lines with a hanging indent that aligns with the opening delimiter.</translate> 
<translate><!--T:14--> For <tvar name="1"><code>if</code></tvar> statements, the conditions should be placed on the next line.</translate>

<syntaxhighlight lang='lua'>
-- Example:

hello = long_function_name(var_one, var_two,
                           var_three, var_four)

if ((condition1
	or condition2)
	and condition3
	and condition4) then
	foo()
	bar()
	baz()
end
</syntaxhighlight>

<translate>
== Naming conventions == <!--T:15-->
</translate>

<translate><!--T:16--> Define the entry method as simply unpacking the parameters from the frame, and then passing those through a function with the same name prefixed with a single underscore.</translate> 
<translate><!--T:17--> This can be disregarded if the function is only useful from wikitext, or if it needs a frame for something other than its arguments.</translate>

<translate><!--T:18--> In the standard library, function names consisting of multiple words are simply put together (e.g. <tvar name="1"><code>setmetatable</code></tvar>).</translate> 
<translate><!--T:19--> Note that camelCase is the preferred way to name functions, in order to avoid potential [[w:garden-path sentence|garden-path]] function names.</translate>

<syntaxhighlight lang='lua'>
-- See https://en.wikipedia.org/w/index.php?oldid=540791109 for code

local p = {}

function p._url(url, text)
	-- Code goes here
end

function p.url(frame)
	-- Take parameters out of the frame and pass them to p._url(). Return the result.
	-- Adapt the below code to your specific template arguments
	local templateArgs = frame.args
	local url = templateArgs[1] or ''
	local text = templateArgs[2] or ''
	return p._url(url, text)
end

return p
</syntaxhighlight>

<translate>
===Highlighting Lua code=== <!--T:20-->
</translate>
<translate><!--T:21--> Outside of a module (like on talkpages), code highlighting can be added using the <tvar name="1">&lt;syntaxhighlight></tvar> tag with the attribute <tvar name="2"><code>lang="lua"</code></tvar>:</translate>

{{SyntaxHighlight source|lang=lua|code=
--code snippet
	function p.main()
		return "Hello world"
	end
}}

<translate><!--T:22--> Produces</translate>:
<syntaxhighlight lang="lua">
--code snippet
	function p.main()
		return "Hello world"
	end
</syntaxhighlight>

<references />

<translate>

== See also == <!--T:10-->
</translate>
* [[Manual:Coding conventions]]

[[Category:Lua{{#translation:}}]]