Module:module documentation

local m_str_utils = require("Module:string utilities")

local codepoint = m_str_utils.codepoint local concat = table.concat local insert = table.insert local u = m_str_utils.char

local export = {}

--[===[ intro: This module automatically generates documentation for other modules. It fetches in-line comments in Lua code and converts them into a form that can be used on a documentation page via module documentation. In fact, this module's documentation is an example of it in action!

It's helpful to do documentation this way, as it means function/method documentation is available in two places: at the top of the module page (as conventional Wikitext), and above the function itself (as a Lua comment). Each suits a different kind of editing style, and doing it this way keeps them synchronised.

A section of documentation is given using Lua's multi-line comment syntax, which looks something like this: {--[==[ ... ]==]}. The number of equal signs should normally be two in order for the documentation to be properly snarfed by module documentation. The following conventions can be used inside of the documentation: or tabs (especially useful in lists, to make the raw comment more readable). In such a case, the newline is converted to a space. Use two newlines in a row to break paragraphs. In general, it's recommended to break lines after at most 120 characters, to facilitate reading the raw comment. braces inside of this literal text will be properly handled as long as they're balanced. If the first character of the literal text is itelf a brace, put a space before it (but not at the end), and it will be ignored. backquotes cannot contain a backquote or extend to multiple lines. The stuff inside of backquotes can only contain letters, numbers, underscores, hyphens and periods.
 * 1) Long lines (both in regular paragraphs and in list items) can be broken by newlines optionally followed by spaces
 * 1) Template calls (using two braces) can be inserted literally and will be expanded.
 * 2) Single braces can be used to surround literal text, and will automatically be syntax-highlighted as Lua code. Nested
 * 1) Backquotes can be used to surround literal text, which will be displayed using { }. The stuff inside of
 * 1) Double backquotes can be used to surround placeholder variable names, which will be displayed using { ... }.

Certain special directives can follow the opening multiline comment indicator, if placed on the same line as the indicator. In particular, the following directives are currently recognized:

documentation. This is useful to give a general introduction/overview of the module. function declared in a nonstandard way (e.g. through a metatable, through an anonymous or locally-declared function assigned to the `export` table, etc.). The directive indicates the desired way for the function to appear, and the remainder of the comment describes the function's operation, as usual. ]===]
 * The directive `intro:` by itself signals introductory text, which will be placed at the beginning, prior to function
 * The directive `func: export. function ( arg1, arg2 , ...)` can be used when documenting a

local function format_doc(str) local code_blocks = {} local code_blocks_i = 0 local private_use_start = 0x100000 return (str		 -- {} blocks: blocks of code		 -- Escape to avoid removing line breaks.		:gsub("%b{}", function(m0) local next_char = m0:sub(2, 2) if next_char == "|" then -- Wikitable; don't try to parse it as code. But we do want to parse special syntax in them (in				-- particular {...} syntax for embedded code snippets), and if we return nil that won't happen. -- Instead, we call format_doc recursively on the innards. return "{" .. format_doc(m0:sub(2, -2)) .. "}"			end if next_char == "{" and m0:sub(-2, -2) == "}" then return nil end local text = " " code_blocks_i = code_blocks_i + 1 code_blocks[code_blocks_i] = text return u(private_use_start + code_blocks_i) end)		-- Join continued lines in a paragraph. We don't want to do that if there are two newlines in a row,		-- and not if the second line begins with whitespace or a certain special characters (#, * or : indicating -- a list item; | indicating a wikitable item; semicolon for bolded items).   	:gsub("([^\n])\n[ \t]*([^ \t\n#*:;|])", "%1 %2")    	-- Repeat the previous in case of a single-character line (admittedly rare).    	:gsub("([^\n])\n[ \t]*([^ \t\n#*:;|])", "%1 %2")		:gsub("\n[ \t]+%f[*#:;]", "\n") -- remove indentation for list items		:gsub("%f[\n,{]\n%f[^\n*#:;]", "\n\n") -- wiki newlines		:gsub("(\n[ *#:]*)(|?[_%w]+=?):", "%1 :") -- parameter names		:gsub("``([A-Za-z0-9_%-.]+)``", " %1 ") -- placeholder variable names between double backquotes		:gsub("`([^`\n]+)`", ' ') -- literal text between backquotes, set using  		:gsub("\244[\128-\191][\128-\191][\128-\191]", function(char) return code_blocks[codepoint(char) - private_use_start] end)) end

--[===[ The main entrypoint for module documentation. The frame object can contain 3 optional arguments: ]===] function export.show(frame) local args = frame:getParent.args or {} local comment_level = tonumber(args["comment_level"]) or 2 local function make_comment_pattern(typeid) if typeid then typeid = "%s*" .. typeid else typeid = "" end return "%-%-%[" .. ("="):rep(comment_level) .. "%[" .. typeid .. "\n?(.-)\n?]" .. ("="):rep(comment_level) .. "]"	end local fn_comment_pattern = make_comment_pattern(nil) local intro_comment_pattern = make_comment_pattern("intro:") local metafunc_comment_pattern = make_comment_pattern("func:%s*(([^\n(]+)[^\n)]+%))")	local section_mark = ("="):rep(tonumber(args["section_level"]) or 2)	local pattern_identifier = args["identifier"] or ""	local mod_title = mw.title.getCurrentTitle	if mod_title.text:match("/documentation$") then return "(The generated documentation is located at the module page.)" end	local mod_text = mod_title:getContent	if not mod_text then return "(The module page does not exist now.)" end
 * |comment_level=: The number of equals signs (=) a given section uses. Default: 2 (i.e. {--[==[ ... (comment block) ]==]})
 * e.g. The value 4 means {--[====[ ... (comment block) ]====]}.
 * |section_level=: The header level used for each function/method. Default: 2 (i.e. L2: {== ... ==}).
 * |identifier=: A Lua string pattern. Only the comments of functions whose names match this pattern are used. When not given, all function are accepted.
 * This is useful when giving object methods, using a pattern such as {^object_name:}.

-- This contains function and intro documentation. Each element is a two-element list of {POSITION, DOCS} specifying -- the generated documentation for a function and the character position in the file where it was found (for sorting	-- purposes). local docs local intro_comment = mod_text:match("^.-" .. intro_comment_pattern) if intro_comment then docs = { {1, format_doc(intro_comment) }} else docs = {} end

-- Look for actual functions. for p0, f, fn in mod_text:gmatch("\n[ \t]*function +(([^\n(]+)[^\n)]+%))") do		if fn:match(pattern_identifier) then						local c = mod_text:sub(1, p0 - 1):match("^.*" .. fn_comment_pattern .. "%s*$")			insert(docs, {p0, section_mark .. fn .. section_mark .. "\n\n" .. " \n\n" .. format_doc(c or				' This function lacks documentation. Please add a description of its usages, inputs and outputs, ' ..				"or its difference from similar functions, or make it local to remove it from the function list. " ..				"")})		end	end

-- Now look for comments with the function declaration inside them (used for metatable functions etc.). for p0, f, fn, comment in mod_text:gmatch("" .. metafunc_comment_pattern) do insert(docs, {p0, section_mark .. fn .. section_mark .. "\n\n" .. " \n\n" .. format_doc(comment)}) end

table.sort(docs, function(a, b) return a[1] < b[1] end) local chunks = {} for i, decl in ipairs(docs) do		insert(chunks, decl[2]) end

return frame:preprocess(concat(chunks, "\n\n")) end

return export