Module:GetShortDescription/sandbox

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Not to be confused with Module:Get short description.

Usage

{{#invoke:GetShortDescription|main |name= |only= |prefer= |fallback= |lang_italic= |lang_nocat= |lang_size= |lang_cat= |lang_rtl= |lang_no= }}

name

By providing only the required page name (including namespace), the module will look for an explicit {{short description}} in that page, but if not found, will try to fetch the wikidata description. If neither are found, the result will be an empty string.

If the result is a wikidata description, and it is declared (at the source) as being of a foreign language (i.e. not en), the result will be appropriately formatted by Module:Lang (the module powering {{lang}}), in accordance with MOS:OTHERLANG; see #Foreign language wikidata descriptions (below).

Markup: {{#invoke:GetShortDescription|main |name=Wikipedia}}

Result: table

This is equivalent to stating |prefer=explicit; see #prefer (below).

only

Providing a value for |only= will limit the search to being only for the stated description. If no description is found, the result will be an empty string, unless a fallback is provided; see #fallback (below).

explicit

Markup: {{#invoke:GetShortDescription|main |name=Wikipedia |only=explicit }}

Result: table

wikidata

Markup: {{#invoke:GetShortDescription|main |name=Wikipedia |only=wikidata }}

Result: table

prefer

Providing a value for |prefer= will initiate the search for the stated description, but try for the alternative if none is found. If no description is found, the result will be an empty string, unless a fallback is provided; see #fallback (below).

explicit or wikidata

Markup: {{#invoke:GetShortDescription|main |name=Wikipedia |prefer=explicit }}

Result: table

wikidata or explicit

Markup: {{#invoke:GetShortDescription|main |name=Wikipedia |prefer=wikidata }}

Result: table

fallback

If a value for |fallback= is provided, and no description is found by the expressed route, the result will be the stated fallback.

only or fallback

Markup: {{#invoke:GetShortDescription|main |name=Example |only=explicit |fallback=This is a fallback }}

Result:

prefer or fallback

Markup: {{#invoke:GetShortDescription|main |name=Example |prefer=wikidata |fallback=This is a fallback }}

Result: table

Foreign language wikidata descriptions

Should a wikidata description be retrieved, which is declared (at the source) as being of a foreign language (i.e. not en), per MOS:OTHERLANG, the return will be formatted as appropriate by Module:Lang by default. This may be disabled with |lang_no=yes or adjusted via the parameters for {{lang}}: |lang_italic=, |lang_nocat=, |lang_size=, |lang_cat= and |lang_rtl=; see lang's documentation for details.

Requiring this module

Instances when a table is returned

Providing a value for |objectify_alarm= will cause alarming messages (red informational messages) to be returned as tables.

Providing a value for |report_redlinks= will cause the return of a report instead of nothing in the event that the page named is nonexistent (i.e. a WP:REDLINK) and a search for a {{short description}} template is processed.

A table will also be returned in the event that the module is instructed to |prefer=explicit (its default), and returns a Wikidata description. If the reason for there being no explicit short description is because it was set to none; the table will include a value for table.none

See below for examples of these behaviors:

local getShortDescription = require( 'Module:GetShortDescription' ).main

local short_description = getShortDescription( {
  -- required
    name = 'page name',

  -- optional
    prefer = 'explicit' or 'wikidata',
    only = 'explicit' or 'wikidata',
    fallback = 'fallback',

    objectify_alarm = true,
    report_redlinks = true,

    lang_no = 'yes',

    -- {{lang}} options
    lang_italic = <yes, no, unset, invert, default>,
    lang_nocat = <yes, y, true, t, on, 1>,
    lang_size = <CSS font-size e.g. '1.5em'>,
    lang_cat = <no, n, false, f, off, 0>,
    lang_rtl = <no (default), yes>
} )

-- If we've requested to report_redlinks or to objectify_alarm then
if type( short_description ) == 'table' then
  if short_description.alarm then
    -- An alarming message has been returned
    local alarming_message = short_description.alarm
  elseif short_description.redlink then
    -- Do something about that
  elseif short_description.wikidata then
    -- A Wikidata description was returned without being explicitly requested
    local wikidata_description = short_description.wikidata
    if short_description.none then
      -- Because the explicit short desc was 'none'
    end
  end
end

The above documentation is transcluded from Module:GetShortDescription/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (edit | run) pages.
Add categories to the /doc subpage. Subpages of this module.

local p = {}

local mLang = require( 'Module:Lang' )

local function errorMessage( message )
	return '<strong class="error">ERROR with invocation of [[Module:GetShortDescription]]: ' .. message .. '</strong>'
end

local function getWikidataDescription( name, lang )
	local wikidata_id = mw.wikibase.getEntityIdForTitle( name )
	if not wikidata_id then
		return nil
	end
	local wikidata_description, wikidata_description_lang = mw.wikibase.getDescriptionWithLang( wikidata_id )
	if not wikidata_description then
		return nil
	end
	-- Do as little as possible; return wikidata_description immediately if no more processing is required.
	if lang.no or wikidata_description_lang == 'en' then
		return wikidata_description
	end
	if not wikidata_description_lang then
		return nil
	end
	return  mLang._lang {
		wikidata_description_lang,
		wikidata_description,
		italic = lang.italic or '',
		nocat = lang.nocat or '',
		size = lang.size or '',
		cat = lang.cat or '',
		rtl = lang.rtl or ''
	}
end

local function getExplicitDescription( name )
	local page_content = mw.title.new( name ):getContent()
	if not page_content then
		return errorMessage( 'could not getContent of [[:' .. name ..  '|' .. name .. ']]' )
	end
	-- Search for a short description template and grab the parameters from it if found.
	-- Do as little as possible; return nil immediately if that's what we found.
	local short_description_content = mw.ustring.match( page_content, '{{%s*[Ss]hort description%s*|%s*(.-)%s*}}' )
	if not short_description_content then
		return nil
	end
	-- The following mess is an alternative to preprocessing, which is expensive and
	-- causes empty strings to be returned if the invocation is substituted.
	-- Why does it look like this though?
	-- Short descriptions defined by template {{short description}} may contain:
		-- a numbered or unnumbered 1st param for the description
		-- a numbered or unnumbered 2nd param for noreplace
		-- the pagetype named param
		-- an empty description
	-- we might therefore need to understand the content of:
		-- {{short description|2=noreplace|pagetype=Redirect|Redirect page}} or
		-- {{short description|2=noreplace|1=Redirect page|pagetype=Redirect}} or
		-- {{short description|pagetype=Redirect|Redirect page|noreplace}} etc.
	-- all with a variety white space.
	-- Split the param content into trimmed param expressions.
	local short_description_params = mw.text.split( short_description_content, '%s*|%s*' )
	local short_description
	-- For each param expession:
	for i, param in ipairs( short_description_params ) do
		-- ignore 'pagetype=<anything>'
		-- ignore 'noreplace' if unnumbered or numbered as '2='
		if not mw.ustring.match( param, '^pagetype%s*=' )
		and not mw.ustring.match( param, '^noreplace$' )
		and not mw.ustring.match( param, '^2%s*=' ) then
			-- Whatever remains is the short description expression.
			short_description = param
			break
		end
	end
	-- The short descrition expression might be in the form
		-- 'short description' or
		-- '1=short description'
	-- If the latter; trim the leading '1='.
	if mw.ustring.match( short_description, '=' ) then
		short_description = mw.ustring.gsub( short_description, '^1%s*=%s*', '' )
	end
	-- Now we know what this template's short description is,
	-- check if it's in use and return nil if not.
	if mw.ustring.match( short_description, '^[Nn]one$' ) then
		short_description = nil
	end
	-- It could still be a completely useless string e.g.
		-- {{short description| &nbsp; &nbsp; &nbsp; &nbsp; }}
		-- creates an 8 character short description of entirely whitespace.
	-- Trim the result before return.
	return mw.ustring.match( short_description, '^%s*([^%s]-)%s*$' )
end

local function getShortDescription( args )
	local name = args.name
	if not name then
		return errorMessage( 'a page name (including namespace) MUST be provided' )
	end
	local result
	local only = args.only
	local prefer = args.prefer or 'explicit'
	local lang = {}
	lang.italic = args.lang_italic
	lang.nocat = args.lang_nocat
	lang.size = args.lang_size
	lang.cat = args.lang_cat
	lang.rtl = args.lang_rtl
	lang.no = args.lang_no
	if only == 'explicit' then
		result = getExplicitDescription( name )
	elseif only == 'wikidata' then
		result = getWikidataDescription( name, lang )
	elseif prefer == 'explicit' then
		result = getExplicitDescription( name ) or getWikidataDescription( name, lang )
	elseif prefer == 'wikidata' then
		result = getWikidataDescription( name, lang ) or getExplicitDescription( name )
	end
	return result or args.fallback
end

function p.main( frame )
	return getShortDescription( frame.args ) or ''
end

return p