Module:Excerpt

 -- 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

 localparser=require('Module:WikitextParser')
 localyesno=require('Module:Yesno')

 localok,config=pcall(require,'Module:Excerpt/config')
 ifnotokthenconfig={}end

 localExcerpt={}

 -- Main entry point for templates
 functionExcerpt.main(frame)

 -- Make sure the requested page exists and get the wikitext
 localpage=Excerpt.getArg(1)
 ifnotpageorpage=='{{{1}}}'thenreturnExcerpt.getError('no-page')end
 localtitle=mw.title.new(page)
 ifnottitlethenreturnExcerpt.getError('invalid-title',page)end
 localfragment=title.fragment-- save for later
 iftitle.isRedirectthen
 title=title.redirectTarget
 iffragment==""then
 fragment=title.fragment-- page merge potential	
 end
 end
 ifnottitle.existsthenreturnExcerpt.getError('page-not-found',page)end
 page=title.prefixedText
 localwikitext=title:getContent()

 -- Get the template params and process them
 localparams={
 hat=yesno(Excerpt.getArg('hat',true)),
 this=Excerpt.getArg('this'),
 only=Excerpt.getArg('only'),
 files=Excerpt.getArg('files',Excerpt.getArg('file')),
 lists=Excerpt.getArg('lists',Excerpt.getArg('list')),
 tables=Excerpt.getArg('tables',Excerpt.getArg('table')),
 templates=Excerpt.getArg('templates',Excerpt.getArg('template')),
 paragraphs=Excerpt.getArg('paragraphs',Excerpt.getArg('paragraph')),
 references=yesno(Excerpt.getArg('references',true)),
 subsections=yesno(Excerpt.getArg('subsections',false)),
 links=yesno(Excerpt.getArg('links',true)),
 bold=yesno(Excerpt.getArg('bold',false)),
 briefDates=yesno(Excerpt.getArg('briefdates',false)),
 inline=yesno(Excerpt.getArg('inline')),
 quote=yesno(Excerpt.getArg('quote')),
 more=yesno(Excerpt.getArg('more')),
 class=Excerpt.getArg('class'),
 track=yesno(Excerpt.getArg('track',true)),
 displayTitle=Excerpt.getArg('displaytitle',page),
 }

 -- Make sure the requested section exists and get the excerpt
 localexcerpt
 localsection=Excerpt.getArg(2,fragment)
 section=mw.text.trim(section)
 ifsection==''thensection=nilend
 ifsectionthen
 excerpt=parser.getSectionTag(wikitext,section)
 ifnotexcerptthen
 ifparams.subsectionsthen
 excerpt=parser.getSection(wikitext,section)
 else
 localsections=parser.getSections(wikitext)
 excerpt=sections[section]
 end
 end
 ifnotexcerptthenreturnExcerpt.getError('section-not-found',section)end
 ifexcerpt==''thenreturnExcerpt.getError('section-empty',section)end
 else
 excerpt=parser.getLead(wikitext)
 ifexcerpt==''thenreturnExcerpt.getError('lead-empty')end
 end

 -- Remove noinclude bits
 excerpt=excerpt:gsub('<[Nn][Oo][Ii][Nn][Cc][Ll][Uu][Dd][Ee]>.-</[Nn][Oo][Ii][Nn][Cc][Ll][Uu][Dd][Ee]>','')

 -- Filter various elements from the excerpt
 excerpt=Excerpt.filterFiles(excerpt,params.files)
 excerpt=Excerpt.filterLists(excerpt,params.lists)
 excerpt=Excerpt.filterTables(excerpt,params.tables)
 excerpt=Excerpt.filterParagraphs(excerpt,params.paragraphs)

 -- If no file is found, try to get one from the infobox
 if(params.only=='file'orparams.only=='files'ornotparams.onlyand(notparams.filesorparams.files~='0'))-- caller asked for files
 andnotsection-- and we're in the lead section
 andconfig.captions-- and we have the config option required to try finding files in infoboxes
 and#parser.getFiles(excerpt)==0-- and there're no files in the excerpt
 then
 excerpt=Excerpt.addInfoboxFile(excerpt)
 end

 -- Filter the templates by appending the templates blacklist to the templates filter
 ifconfig.blacklistthen
 localblacklist=table.concat(config.blacklist,',')
 ifparams.templatesthen
 ifstring.sub(params.templates,1,1)=='-'then
 params.templates=params.templates..','..blacklist
 end
 else
 params.templates='-'..blacklist
 end
 end
 excerpt=Excerpt.filterTemplates(excerpt,params.templates)

 -- Leave only the requested elements
 ifparams.only=='file'orparams.only=='files'then
 localfiles=parser.getFiles(excerpt)
 excerpt=params.only=='file'andfiles[1]ortable.concat(files,'\n\n')
 end
 ifparams.only=='list'orparams.only=='lists'then
 locallists=parser.getLists(excerpt)
 excerpt=params.only=='list'andlists[1]ortable.concat(lists,'\n\n')
 end
 ifparams.only=='table'orparams.only=='tables'then
 localtables=parser.getTables(excerpt)
 excerpt=params.only=='table'andtables[1]ortable.concat(tables,'\n\n')
 end
 ifparams.only=='paragraph'orparams.only=='paragraphs'then
 localparagraphs=parser.getParagraphs(excerpt)
 excerpt=params.only=='paragraph'andparagraphs[1]ortable.concat(paragraphs,'\n\n')
 end
 ifparams.only=='template'orparams.only=='templates'then
 localtemplates=parser.getTemplates(excerpt)
 excerpt=params.only=='template'andtemplates[1]ortable.concat(templates,'\n\n')
 end

 -- @todo Make more robust and move downwards
 ifparams.briefDatesthen
 excerpt=Excerpt.fixDates(excerpt)
 end

 -- Remove unwanted elements
 excerpt=Excerpt.removeComments(excerpt)
 excerpt=Excerpt.removeSelfLinks(excerpt)
 excerpt=Excerpt.removeNonFreeFiles(excerpt)
 excerpt=Excerpt.removeBehaviorSwitches(excerpt)

 -- Fix or remove the references
 ifparams.referencesthen
 excerpt=Excerpt.fixReferences(excerpt,page,wikitext)
 else
 excerpt=Excerpt.removeReferences(excerpt)
 end

 -- Remove wikilinks
 ifnotparams.linksthen
 excerpt=Excerpt.removeLinks(excerpt)
 end

 -- Link the bold text near the start of most leads and then remove it
 ifnotsectionthen
 excerpt=Excerpt.linkBold(excerpt,page)
 end
 ifnotparams.boldthen
 excerpt=Excerpt.removeBold(excerpt)
 end

 -- Remove extra line breaks but leave one before and after so the parser interprets lists, tables, etc. correctly
 excerpt=excerpt:gsub('\n\n\n+','\n\n')
 excerpt=mw.text.trim(excerpt)
 excerpt='\n'..excerpt..'\n'

 -- Remove nested categories
 excerpt=frame:preprocess(excerpt)
 excerpt=Excerpt.removeCategories(excerpt)

 -- Add tracking categories
 ifparams.trackandconfig.categoriesthen
 excerpt=Excerpt.addTrackingCategories(excerpt)
 end

 -- Build the final output
 ifparams.inlinethen
 returnmw.text.trim(excerpt)
 end

 localtag=params.quoteand'blockquote'or'div'
 localblock=mw.html.create(tag):addClass('excerpt-block'):addClass(params.class)

 ifconfig.stylesthen
 localstyles=frame:extensionTag('templatestyles','',{src=config.styles})
 block:node(styles)
 end

 ifparams.hatthen
 localhat=Excerpt.getHat(page,section,params)
 block:node(hat)
 end

 excerpt=mw.html.create('div'):addClass('excerpt'):wikitext(excerpt)
 block:node(excerpt)

 ifparams.morethen
 localmore=Excerpt.getReadMore(page,section)
 block:node(more)
 end

 returnblock
 end

 -- Filter the files in the given wikitext against the given filter
 functionExcerpt.filterFiles(wikitext,filter)
 ifnotfilterthenreturnwikitextend
 localfilters,isBlacklist=Excerpt.parseFilter(filter)
 localfiles=parser.getFiles(wikitext)
 forindex,fileinpairs(files)do
 localname=parser.getFileName(file)
 ifisBlacklistand(Excerpt.matchFilter(index,filters)orExcerpt.matchFilter(name,filters))
 ornotisBlacklistand(notExcerpt.matchFilter(index,filters)andnotExcerpt.matchFilter(name,filters))then
 wikitext=Excerpt.removeString(wikitext,file)
 end
 end
 returnwikitext
 end

 -- Filter the lists in the given wikitext against the given filter
 functionExcerpt.filterLists(wikitext,filter)
 ifnotfilterthenreturnwikitextend
 localfilters,isBlacklist=Excerpt.parseFilter(filter)
 locallists=parser.getLists(wikitext)
 forindex,listinpairs(lists)do
 ifisBlacklistandExcerpt.matchFilter(index,filters)
 ornotisBlacklistandnotExcerpt.matchFilter(index,filters)then
 wikitext=Excerpt.removeString(wikitext,list)
 end
 end
 returnwikitext
 end

 -- Filter the tables in the given wikitext against the given filter
 functionExcerpt.filterTables(wikitext,filter)
 ifnotfilterthenreturnwikitextend
 localfilters,isBlacklist=Excerpt.parseFilter(filter)
 localtables=parser.getTables(wikitext)
 forindex,tableWikitextinpairs(tables)do
 localid=parser.getTableAttribute(tableWikitext,'id')
 ifisBlacklistand(Excerpt.matchFilter(index,filters)orExcerpt.matchFilter(id,filters))
 ornotisBlacklistand(notExcerpt.matchFilter(index,filters)andnotExcerpt.matchFilter(id,filters))then
 wikitext=Excerpt.removeString(wikitext,tableWikitext)
 end
 end
 returnwikitext
 end

 -- Filter the paragraphs in the given wikitext against the given filter
 functionExcerpt.filterParagraphs(wikitext,filter)
 ifnotfilterthenreturnwikitextend
 localfilters,isBlacklist=Excerpt.parseFilter(filter)
 localparagraphs=parser.getParagraphs(wikitext)
 forindex,paragraphinpairs(paragraphs)do
 ifisBlacklistandExcerpt.matchFilter(index,filters)
 ornotisBlacklistandnotExcerpt.matchFilter(index,filters)then
 wikitext=Excerpt.removeString(wikitext,paragraph)
 end
 end
 returnwikitext
 end

 -- Filter the templates in the given wikitext against the given filter
 functionExcerpt.filterTemplates(wikitext,filter)
 ifnotfilterthenreturnwikitextend
 localfilters,isBlacklist=Excerpt.parseFilter(filter)
 localtemplates=parser.getTemplates(wikitext)
 forindex,templateinpairs(templates)do
 localname=parser.getTemplateName(template)
 ifisBlacklistand(Excerpt.matchFilter(index,filters)orExcerpt.matchFilter(name,filters))
 ornotisBlacklistand(notExcerpt.matchFilter(index,filters)andnotExcerpt.matchFilter(name,filters))then
 wikitext=Excerpt.removeString(wikitext,template)
 end
 end
 returnwikitext
 end

 functionExcerpt.addInfoboxFile(excerpt)
 -- We cannot distinguish the infobox from the other templates, so we search them all
 localtemplates=parser.getTemplates(excerpt)
 for_,templateinpairs(templates)do
 localparameters=parser.getTemplateParameters(template)
 localfile,captions,caption,cssClasses,cssClass
 for_,pairinpairs(config.captions)do
 file=pair[1]
 file=parameters[file]
 iffileandExcerpt.matchAny(file,'^.*%.',{'[Jj][Pp][Ee]?[Gg]','[Pp][Nn][Gg]','[Gg][Ii][Ff]','[Ss][Vv][Gg]'},'.*')then
 file=string.match(file,'%[?%[?.-:([^{|]+)%]?%]?')orfile-- [[File:Example.jpg{{!}}upright=1.5]] to Example.jpg
 captions=pair[2]
 for_,pinpairs(captions)do
 ifparameters[p]thencaption=parameters[p]breakend
 end
 -- Check for CSS classes
 -- We opt to use skin-invert-image instead of skin-invert
 -- in all other cases, the CSS provided in the infobox is used
 ifpair[3]then
 cssClasses=pair[3]
 for_,pinpairs(cssClasses)do
 ifparameters[p]then
 cssClass=(parameters[p]=='skin-invert')and'skin-invert-image'orparameters[p]
 break
 end
 end
 end
 localclass=cssClassand('|class='..cssClass)or''
 return'[[File:'..file..class..'|thumb|'..(captionor'')..']]'..excerpt
 end
 end
 end
 returnexcerpt
 end

 functionExcerpt.removeNonFreeFiles(wikitext)
 localfiles=parser.getFiles(wikitext)
 for_,fileinpairs(files)do
 localfileName='File:'..parser.getFileName(file)
 localfileTitle=mw.title.new(fileName)
 iffileTitlethen
 localfileDescription=fileTitle:getContent()
 ifnotfileDescriptionorfileDescription==''then
 localframe=mw.getCurrentFrame()
 fileDescription=frame:preprocess('{{'..fileName..'}}')-- try Commons
 end
 iffileDescriptionandstring.match(fileDescription,'[Nn]on%-free')then
 wikitext=Excerpt.removeString(wikitext,file)
 end
 end
 end
 returnwikitext
 end

 functionExcerpt.getHat(page,section,params)
 localhat

 -- Build the text
 ifparams.thisthen
 hat=params.this
 elseifparams.quotethen
 hat=Excerpt.getMessage('this')
 elseifparams.onlythen
 hat=Excerpt.getMessage(params.only)
 else
 hat=Excerpt.getMessage('section')
 end
 hat=hat..' '..Excerpt.getMessage('excerpt')

 -- Build the link
 ifsectionthen
 hat=hat..' [[:'..page..'#'..mw.uri.anchorEncode(section)..'|'..params.displayTitle
 ..' § '..section:gsub('%[%[([^]|]+)|?[^]]*%]%]','%1')..']].'-- remove nested links
 else
 hat=hat..' [[:'..page..'|'..params.displayTitle..']].'
 end

 -- Build the edit link
 localtitle=mw.title.new(page)
 localeditUrl=title:fullUrl('action=edit')
 hat=hat..'<span class="mw-editsection-like plainlinks"><span class="mw-editsection-bracket">[</span>['
 hat=hat..editUrl..' '..mw.message.new('editsection'):plain()
 hat=hat..']<span class="mw-editsection-bracket">]</span></span>'

 ifconfig.hatthen
 localframe=mw.getCurrentFrame()
 hat=config.hat..hat..'}}'
 hat=frame:preprocess(hat)
 else
 hat=mw.html.create('div'):addClass('dablink excerpt-hat'):wikitext(hat)
 end

 returnhat
 end

 functionExcerpt.getReadMore(page,section)
 locallink="'''[["..page
 ifsectionthen
 link=link..'#'..section
 end
 localtext=Excerpt.getMessage('more')
 link=link..'|'..text.."]]'''"
 link=mw.html.create('div'):addClass('noprint excerpt-more'):wikitext(link)
 returnlink
 end

 -- Fix birth and death dates, but only in the first paragraph
 -- @todo Use parser.getParagraphs() to get the first paragraph
 functionExcerpt.fixDates(excerpt)
 localstart=1-- skip initial templates
 locals
 locale=0
 repeat
 start=e+1
 s,e=mw.ustring.find(excerpt,'%s*%b{}%s*',start)
 untilnotsors>start
 s,e=mw.ustring.find(excerpt,'%b()',start)-- get (...), which may be (year–year)
 ifsands<start+100then-- look only near the start
 localexcerptStart=mw.ustring.sub(excerpt,s,e)
 localyear1,conjunction,year2=string.match(excerptStart,'(%d%d%d+)(.-)(%d%d%d+)')
 ifyear1andyear2and(string.match(conjunction,'[%-–—]')orstring.match(conjunction,'{{%s*[sS]nd%s*}}'))then
 localy1=tonumber(year1)
 localy2=tonumber(year2)
 ify2>y1andy2<y1+125andy1<=tonumber(os.date('%Y'))then
 excerpt=mw.ustring.sub(excerpt,1,s)..year1..'–'..year2..mw.ustring.sub(excerpt,e)
 end
 end
 end
 returnexcerpt
 end

 -- Replace the first call to each reference defined outside of the excerpt for the full reference, to prevent undefined references
 -- Then prefix the page title to the reference names to prevent conflicts
 -- that is, replace <ref name="Foo"> for <ref name="Title of the article Foo">
 -- and also <ref name="Foo" /> for <ref name="Title of the article Foo" />
 -- also remove reference groups: <ref name="Foo" group="Bar"> for <ref name="Title of the article Foo">
 -- and <ref group="Bar"> for <ref>
 -- @todo The current regex may fail in cases with both kinds of quotes, like <ref name="Darwin's book">
 functionExcerpt.fixReferences(excerpt,page,wikitext)
 localreferences=parser.getReferences(excerpt)
 localfixed={}
 for_,referenceinpairs(references)do
 localname=parser.getTagAttribute(reference,'name')
 ifnotfixed[name]then-- fix each reference only once
 localcontent=parser.getTagContent(reference)
 ifnotcontentthen-- reference is self-closing
 localfull=parser.getReference(excerpt,name)
 ifnotfullthen-- the reference is not defined in the excerpt
 full=parser.getReference(wikitext,name)
 iffullthen
 excerpt=excerpt:gsub(Excerpt.escapeString(reference),Excerpt.escapeString(full),1)
 end
 table.insert(fixed,name)
 end
 end
 end
 end
 -- Prepend the page title to the reference names to prevent conflicts with other references in the transcluding page
 excerpt=excerpt:gsub('< *[Rr][Ee][Ff][^>]*name *= *["\']?([^"\'>/]+)["\']?[^>/]*(/?) *>','<ref name="'..page:gsub('"','')..' %1"%2>')
 -- Remove reference groups because they don't apply to the transcluding page
 excerpt=excerpt:gsub('< *[Rr][Ee][Ff] *group *= *["\']?[^"\'>/]+["\'] *>','<ref>')
 returnexcerpt
 end

 functionExcerpt.removeReferences(excerpt)
 localreferences=parser.getReferences(excerpt)
 for_,referenceinpairs(references)do
 excerpt=Excerpt.removeString(excerpt,reference)
 end
 returnexcerpt
 end

 functionExcerpt.removeCategories(excerpt)
 localcategories=parser.getCategories(excerpt)
 for_,categoryinpairs(categories)do
 excerpt=Excerpt.removeString(excerpt,category)
 end
 returnexcerpt
 end

 functionExcerpt.removeBehaviorSwitches(excerpt)
 returnexcerpt:gsub('__[A-Z]+__','')
 end

 functionExcerpt.removeComments(excerpt)
 returnexcerpt:gsub('<!%-%-.-%-%->','')
 end

 functionExcerpt.removeBold(excerpt)
 returnexcerpt:gsub("'''",'')
 end

 functionExcerpt.removeLinks(excerpt)
 locallinks=parser.getLinks(excerpt)
 for_,linkinpairs(links)do
 excerpt=Excerpt.removeString(excerpt,link)
 end
 returnexcerpt
 end

 -- @todo Use parser.getLinks
 functionExcerpt.removeSelfLinks(excerpt)
 locallang=mw.language.getContentLanguage()
 localpage=Excerpt.escapeString(mw.title.getCurrentTitle().prefixedText)
 localucpage=lang:ucfirst(page)
 locallcpage=lang:lcfirst(page)
 excerpt=excerpt
 :gsub('%[%[('..ucpage..')%]%]','%1')
 :gsub('%[%[('..lcpage..')%]%]','%1')
 :gsub('%[%['..ucpage..'|([^]]+)%]%]','%1')
 :gsub('%[%['..lcpage..'|([^]]+)%]%]','%1')
 returnexcerpt
 end

 -- Replace the bold title or synonym near the start of the page by a link to the page
 functionExcerpt.linkBold(excerpt,page)
 locallang=mw.language.getContentLanguage()
 localposition=mw.ustring.find(excerpt,"'''"..lang:ucfirst(page).."'''",1,true)-- look for "'''Foo''' is..." (uc) or "A '''foo''' is..." (lc)
 ormw.ustring.find(excerpt,"'''"..lang:lcfirst(page).."'''",1,true)-- plain search: special characters in page represent themselves
 ifpositionthen
 locallength=mw.ustring.len(page)
 excerpt=mw.ustring.sub(excerpt,1,position+2)..'[['..mw.ustring.sub(excerpt,position+3,position+length+2)..']]'..mw.ustring.sub(excerpt,position+length+3,-1)-- link it
 else-- look for anything unlinked in bold, assumed to be a synonym of the title (e.g. a person's birth name)
 excerpt=mw.ustring.gsub(excerpt,"'''(.-'*)'''",function(text)
 ifnotstring.find(text,'%[')andnotstring.find(text,'%{')then-- if not wikilinked or some weird template
 return"'''[["..page..'|'..text.."]]'''"-- replace '''Foo''' by '''[[page|Foo]]'''
 else
 returnnil-- instruct gsub to make no change
 end
 end,1)-- terminates the anonymous replacement function passed to gsub
 end
 returnexcerpt
 end

 functionExcerpt.addTrackingCategories(excerpt)
 localcurrentTitle=mw.title.getCurrentTitle()
 localcontentCategory=config.categories.content
 ifcontentCategoryandcurrentTitle.isContentPagethen
 excerpt=excerpt..'[[Category:'..contentCategory..']]'
 end
 localnamespaceCategory=config.categories[currentTitle.namespace]
 ifnamespaceCategorythen
 excerpt=excerpt..'[[Category:'..namespaceCategory..']]'
 end
 returnexcerpt
 end

 -- Helper method to match from a list of regular expressions
 -- Like so: match pre..list[1]..post or pre..list[2]..post or ...
 functionExcerpt.matchAny(text,pre,list,post,init)
 localmatch={}
 fori=1,#listdo
 match={mw.ustring.match(text,pre..list[i]..post,init)}
 ifmatch[1]thenreturnunpack(match)end
 end
 returnnil
 end

 -- Helper function to get arguments
 -- args from Lua calls have priority over parent args from template
 functionExcerpt.getArg(key,default)
 localframe=mw.getCurrentFrame()
 fork,valueinpairs(frame:getParent().args)do
 ifk==keyandmw.text.trim(value)~=''then
 returnvalue
 end
 end
 fork,valueinpairs(frame.args)do
 ifk==keyandmw.text.trim(value)~=''then
 returnvalue
 end
 end
 returndefault
 end

 -- Helper method to get an error message
 -- This method also categorizes the current page in one of the configured error categories
 functionExcerpt.getError(key,value)
 localmessage=Excerpt.getMessage('error-'..key,value)
 localmarkup=mw.html.create('div'):addClass('error'):wikitext(message)
 ifconfig.categoriesandconfig.categories.errorsandmw.title.getCurrentTitle().isContentPagethen
 markup:node('[[Category:'..config.categories.errors..']]')
 end
 returnmarkup
 end

 -- Helper method to get a localized message
 -- This method uses Module:TNT to get localized messages from https://commons.wikimedia.org/wiki/Data:I18n/Module:Excerpt.tab
 -- If Module:TNT is not available or the localized message does not exist, the key is returned instead
 functionExcerpt.getMessage(key,value)
 localok,TNT=pcall(require,'Module:TNT')
 ifnotokthenreturnkeyend
 localok2,message=pcall(TNT.format,'I18n/Module:Excerpt.tab',key,value)
 ifnotok2thenreturnkeyend
 returnmessage
 end

 -- Helper method to escape a string for use in regexes
 functionExcerpt.escapeString(str)
 returnstr:gsub('[%^%$%(%)%.%[%]%*%+%-%?%%]','%%%0')
 end

 -- Helper method to remove a string from a text
 -- @param text Text from where to remove the string
 -- @param str String to remove
 -- @return The given text with the string removed
 functionExcerpt.removeString(text,str)
 localpattern=Excerpt.escapeString(str)
 if#pattern>9999then-- strings longer than 10000 bytes can't be put into regexes
 pattern=Excerpt.escapeString(mw.ustring.sub(str,1,999))..'.-'..Excerpt.escapeString(mw.ustring.sub(str,-999))
 end
 returntext:gsub(pattern,'')
 end

 -- Helper method to convert a comma-separated list of numbers or min-max ranges into a list of booleans
 -- @param filter Required. Comma-separated list of numbers or min-max ranges, for example '1,3-5'
 -- @return Map from integers to booleans, for example {1=true,2=false,3=true,4=true,5=true}
 -- @return Boolean indicating whether the filters should be treated as a blacklist or not
 -- @note Merging this into matchFilter is possible, but way too inefficient
 functionExcerpt.parseFilter(filter)
 localfilters={}
 localisBlacklist=false
 ifstring.sub(filter,1,1)=='-'then
 isBlacklist=true
 filter=string.sub(filter,2)
 end
 localvalues=mw.text.split(filter,',')-- split values: '1,3-5' to {'1','3-5'}
 for_,valueinpairs(values)do
 value=mw.text.trim(value)
 localmin,max=mw.ustring.match(value,'^(%d+)%s*[-–—]%s*(%d+)$')-- '3-5' to min=3 max=5
 ifnotmaxthenmin,max=string.match(value,'^((%d+))$')end-- '1' to min=1 max=1
 ifmaxthen
 fori=min,maxdofilters[i]=trueend
 else
 filters[value]=true-- if we reach this point, the string had the form 'a,b,c' rather than '1,2,3'
 end
 end
 localfilter={cache={},terms=filters}
 returnfilter,isBlacklist
 end

 -- Helper function to see if a value matches any of the given filters
 functionExcerpt.matchFilter(value,filter)
 ifvalue==nilthen
 returnfalse
 elseiftype(value)=="number"then
 returnfilter.terms[value]
 else
 localcached=filter.cache[value]
 ifcached~=nilthen
 returncached
 end
 locallang=mw.language.getContentLanguage()
 locallcvalue=lang:lcfirst(value)
 localucvalue=lang:ucfirst(value)
 forterminpairs(filter.terms)do
 ifvalue==tostring(term)
 ortype(term)=="string"and(
 lcvalue==term
 orucvalue==term
 ormw.ustring.match(value,term)
 )then
 filter.cache[value]=true
 returntrue
 end
 end
 filter.cache[value]=false
 end
 end

 returnExcerpt