Module:Extract short description

require('strict');

--[[--< E X T R A C T _ F R O M _ T E M P L A T E >

no direct template access

extracts short description text from a named template in the named article when that template is found in article wiki source

requires three arguments: frame: frame object required to preprocess template_name article_title: the name of the article to inspect - correct spelling and captialization is required template_names_tbl: a single template name (a string) or a table of one or more template names all without namespace to be inspected - correct spelling and captialization is required

returns two values: on success, returns the short description text and true on failure, returns error message and nil

]]

local function extract_from_template (frame, article_title, template_names_tbl) local content = mw.title.new (article_title):getContent;					-- read the unparsed article source if not content then return ' error: no article: ' .. article_title .. ' ';	end

local template_name_pattern; local start; if 'string' == type (template_names_tbl) then								-- when single template name passed in as a string template_names_tbl = {template_names_tbl};								-- convert to a table end local templateName for _, template_name in ipairs (template_names_tbl) do						-- loop through the name in the table template_name_pattern = template_name:gsub ('^%a', string.lower):gsub ('^%a', '%[%1%1%]'):gsub ('%[%a', string.upper);	-- make lua pattern for initial letter upper or lower case: A -> [Aa] start = content:find ('{{%s*' .. template_name_pattern);				-- find the start of {{template name ...; if start then templateName = template_name break;																-- found a matching template end end

if not start then															-- no templates found: return name of first template in template_names_tbl in error message return ' error: no template: ' .. template_names_tbl[1] .. ' in: ' .. article_title .. ' ';	end

local text = string.match (content, '%b{}', start);							-- start points to first { of the templateName if not text then return ' error: failed to extract template: ' .. templateName .. ' ';	end

text = text:gsub (']->[^<]- ', '');								-- delete references before preprocessing; they do not belong in shortdesc text text = text:gsub (']-/ *>', '');										-- also delete self-closed named references text = text:gsub ('{{%s*sfn[^}]-}}', '');									-- delete sfn template which make references using {{#tag:}} parser functions text = text:gsub ('{{#tag:ref[^}]-}}', '');									-- and delete these too

text = frame:preprocess (text):match (']-class="shortdescription.->(.-) ');		-- preprocess and extract shortdescription text	if not text then		return ' error: no short description text in: ' .. templateName .. ' in '.. article_title .. ' ';	end

return mw.text.trim (text), true;											-- trim whitespace and done -- preprocess the template then apply syntax highlighting -- this will display the preprocessed template; not usable here -- for much other than debugging because syntaxhighlight returns a stripmarker --	return template_name .. frame:callParserFunction ('#tag:syntaxhighlight', frame:preprocess (text)); end

--[[--< E X T R A C T _ F R O M _ A R T I C L E >--

no direct template access

extracts short description text from {{short description}} template when that template is found in article wiki source; searches for both the long name (short description) and the short-name redirect (SHD); if both are present long name controls; if multiples of the same name are present, the first-found controls.

requires one argument: article_title is the name of the article to be inspected

on success, returns the short description text; error message else

]]

local function extract_from_article (article_title) local content = mw.title.new (article_title):getContent;					-- read the unparsed article source if not content then return ' error: no article: ' .. article_title .. ' ';	end

local text, start; start = string.find (content, '{{%s*[Ss]hort description') or				-- find the start of {{Short description}} template string.find (content, '{{%s*SHD');										-- not full name, try the {{SHD}} redirect

if not start then return ' error: no short description in: ' .. article_title .. ' ';	end

text = content:match ('%b{}', start);										-- get the short description template; start points to first { of the template if not text then return ' error: failed to extract short description template from ' .. article_title .. ' ';	end

text = text:match ('^[^|}]+|%s*(.+)%s*}}$');								-- strip '{{template name|' and '}}'; trim leading and trailing whitespace return text and text or ' error: no short description text in: ' .. article_title .. ' '; end

--[[--< E X T R A C T _ S H O R T _ D E S C R I P T I O N >

template entry point: {{#invoke:extract short description|extract_short_description}}

search for and return text that is used by the {{short description}} template. {{Short description}}, also {{SHD}} may be located in article wikisource or embedded in a template (commonly an infobox template). When neither of named template.
 * template= and {{{2|}}} are set, this code will look in the article wiki source; when set, this code look inside the

This template entry takes two parameters: {{{1}}} or |article=: required; name of wiki article from which to extract the short description {{{2}}} or |template=; optional; name of template that holds the {{short description}} template

on success, returns the short description text; error message else

]]

local function extract_short_description (frame) local getArgs = require('Module:Arguments').getArgs; local args = getArgs(frame); if args[1] and args.article then											-- both assigned, fail with an error message return ' error: conflicting |{{{1}}} and |article= parameters '; end local article_title = args[1] or args.article;								-- the required parameter if not article_title then													-- not supplied, fail with an error message return ' error: article title required '; end local template_name = args[2] or args.template;								-- optional if template_name then local text, _ = extract_from_template (frame, article_title, template_name);	-- ignore second return value return text; else return extract_from_article (article_title); end end

----< E X P O R T E D  F U N C T I O N S >--

return { extract_short_description = extract_short_description, extract_from_template = extract_from_template, extract_from_article = extract_from_article, }