-- Module:Excerpt implements the Excerpt template
-- Documentation and master version: https://en.wikipedia.org/wiki/Module:Excerpt
-- Authors: User:Sophivorus, User:Certes, User:Aidan9382 & others
-- License: CC-BY-SA-3.0  
local Transcluder = require( 'Module:Transcluder' )  
local yesno = require( 'Module:Yesno' )  
local ok, config = pcall( require, 'Module:Excerpt/config' )
if not ok then config = {} end  
local p = {}  
-- Helper function to get arguments
local args
local function getArg( key, default )
local value = args[ key ]
if value and mw.text.trim( value ) ~= '' then
return value
end
return default
end  
-- Helper function to handle errors
local function getError( message, value )
if type( message ) == 'string' then
message = Transcluder.getError( message, value )
end
if config.categories and config.categories.errors and mw.title.getCurrentTitle.isContentPage then
message:node( '' )
end
return message
end  
-- Helper function to get localized messages
local function getMessage( key )
local ok, TNT = pcall( require, 'Module:TNT' )
if not ok then return key end
return TNT.format( 'I18n/Module:Excerpt.tab', key )
end  
-- Main entry point for templates
function p.main
args = Transcluder.parseArgs  
-- Make sure the requested page exists
local page = getArg( 1 )
if not page or page == '}' then return getError( 'no-page' ) end
local title = mw.title.new(page)
if not title then return getError( 'invalid-title', page ) end
if title.isRedirect then title = title.redirectTarget end
if not title.exists then return getError( 'page-not-found', page ) end
page = title.prefixedText  
-- Set variables from the template parameters
local section = getArg( 2, mw.ustring.match( getArg( 1 ), '[^#]+#(.+)' ) )
local hat = yesno( getArg( 'hat', true ) )
local edit = yesno( getArg( 'edit', true ) )
local this = getArg( 'this' )
local only = getArg( 'only' )
local files = getArg( 'files', getArg( 'file', ( only == 'file' and 1 ) ) )
local lists = getArg( 'lists', getArg( 'list', ( only == 'list' and 1 ) ) )
local tables = getArg( 'tables', getArg( 'table', ( only == 'table' and 1 ) ) )
local templates = getArg( 'templates', getArg( 'template', ( only == 'template' and 1 ) ) )
local paragraphs = getArg( 'paragraphs', getArg( 'paragraph', ( only == 'paragraph' and 1 ) ) )
local references = getArg( 'references' )
local subsections = not yesno( getArg( 'subsections' ) )
local noLinks = not yesno( getArg( 'links', true ) )
local noBold = not yesno( getArg( 'bold' ) )
local onlyFreeFiles = yesno( getArg( 'onlyfreefiles', true ) )
local briefDates = yesno( getArg( 'briefdates', false ) )
local inline = yesno( getArg( 'inline' ) )
local quote = yesno( getArg( 'quote' ) )
local more = yesno( getArg( 'more' ) )
local class = getArg( 'class' )
local displaytitle = getArg( 'displaytitle' ) or page  
-- Build the hatnote
if hat and not inline then
if this then
hat = this
elseif quote then
hat = getMessage( 'this' )
elseif only then
hat = getMessage( only )
else
hat = getMessage( 'section' )
end
hat = hat .. ' ' .. getMessage( 'excerpt' ) .. ' '
if section then
hat = hat .. '[[:' .. page .. '#' .. mw.uri.anchorEncode( section ) .. '|' .. displaytitle
.. ' § ' .. mw.ustring.gsub( section, '%[%[([^]|]+)|?[^]]*%]%]', '%1' ) .. ']].' -- remove nested links
else
hat = hat .. '' .. displaytitle .. '.'
end
if edit then
hat = hat .. '<span><span>[</span>['
hat = hat .. title:fullUrl( 'action=edit' ) .. ' ' .. mw.message.new( 'editsection' ):plain
hat = hat .. ']<span>]</span></span>'
end
if config.hat then
hat = config.hat .. hat .. '}}'
hat = :preprocess( hat )
else
hat = mw.html.create( 'div' ):addClass( 'dablink excerpt-hat' ):wikitext( hat )
end
else
hat = nil
end  
-- Build the "Read more" link
if more and not inline then
more = "**" .. getMessage( 'more' ) .. "**"
more = mw.html.create( 'div' ):addClass( 'noprint excerpt-more' ):wikitext( more )
else
more = nil
end  
-- Build the options for Module:Transcluder out of the template parameters and the desired defaults
local options = {
files = files,
lists = lists,
tables = tables,
paragraphs = paragraphs,
sections = subsections,
categories = 0,
references = references,
only = only and mw.text.trim( only, 's' ) .. 's',
noLinks = noLinks,
noBold = noBold,
noSelfLinks = true,
noNonFreeFiles = onlyFreeFiles,
noBehaviorSwitches = true,
fixReferences = true,
linkBold = true,
}  
-- Get the excerpt itself
local title = page .. '#' .. ( section or '' )
local ok, excerpt = pcall( Transcluder.get, title, options )
if not ok then return getError( excerpt ) end
if mw.text.trim( excerpt ) == '' and not only then
if section then return getError( 'section-empty', section ) else return getError( 'lead-empty' ) end
end  
-- Fix birth and death dates, but only in the first paragraph
if briefDates then
local startpos = 1 -- skip initial templates
local s
local e = 0
repeat
startpos = e + 1
s, e = mw.ustring.find( excerpt, "%s*%b{}%s*", startpos )
until not s or s > startpos
s, e = mw.ustring.find( excerpt, "%b", startpos ) -- get (...), which may be (year–year)
if s and s < startpos + 100 then -- look only near the start
local year1, conjunction, year2 = mw.ustring.match( mw.ustring.sub( excerpt, s, e ), '(%d%d%d+)(.-)(%d%d%d+)' )
if year1 and year2 and (mw.ustring.match( conjunction, '[%-–—]' ) or mw.ustring.match( conjunction, '' )) then
local y1 = tonumber(year1)
local y2 = tonumber(year2)
if y2 > y1 and y2 < y1 + 125 and y1 <= tonumber( os.date( "%Y" )) then
excerpt = mw.ustring.sub( excerpt, 1, s ) .. year1 .. "–" .. year2 .. mw.ustring.sub( excerpt, e )
end
end
end
end  
-- If no file was found, try to get one from the infobox
local fileNamespaces = Transcluder.getNamespaces( 'File' )
if ( ( only == 'file' or only == 'files' ) or ( not only and ( files ~= '0' or not files ) ) ) and -- caller asked for files
not Transcluder.matchAny( excerpt, '%[%[', fileNamespaces, ':' ) and -- and there are no files in Transcluder's output
config.captions -- and we have the config option required to try finding files in templates
then
-- We cannot distinguish the infobox from the other templates so we search them all
local infobox = Transcluder.getTemplates( excerpt );
infobox = table.concat( infobox )
local parameters = Transcluder.getParameters( infobox )
local file, captions, caption
for _, pair in pairs( config.captions ) do
file = pair[1]
file = parameters[file]
if file and Transcluder.matchAny( file, '^.*%.', { '[Jj][Pp][Ee]?[Gg]', '[Pp][Nn][Gg]', '[Gg][Ii][Ff]', '[Ss][Vv][Gg]' }, '.*' ) then
file = mw.ustring.match( file, '%[?%[?.-:([^{|]+)%]?%]?' ) or file -- to Example.jpg
captions = pair[2]
for _, p in pairs( captions ) do
if parameters[ p ] then caption = parameters[ p ] break end
end
excerpt = '' .. excerpt
if ( onlyFreeFiles ) then
excerpt = Transcluder.removeNonFreeFiles( excerpt )
end
break
end
end
end  
-- Unlike other elements, templates are filtered here
-- because we had to search the infoboxes for files
local trash
if only and ( only == 'template' or only == 'templates' ) then
trash, excerpt = Transcluder.getTemplates( excerpt, templates );
else -- Remove blacklisted templates
local blacklist = config.blacklist and table.concat( config.blacklist, ',' ) or ''
if templates then
if string.sub( templates, 1, 1 ) == '-' then --Unwanted templates. Append to blacklist
blacklist = templates .. ',' .. blacklist
else --Wanted templates. Replaces blacklist and acts as whitelist
blacklist = templates
end
else
blacklist = '-' .. blacklist
end
trash, excerpt = Transcluder.getTemplates( excerpt, blacklist );
end  
-- Remove extra line breaks but leave one before and after so the parser interprets lists, tables, etc. correctly
excerpt = mw.text.trim( excerpt )
excerpt = string.gsub( excerpt, '\n\n\n+', '\n\n' )
excerpt = '\n' .. excerpt .. '\n'  
-- Remove nested categories
excerpt = :preprocess( excerpt )
local categories, excerpt = Transcluder.getCategories( excerpt, options.categories )  
-- Add tracking categories
if config.categories then