Module:Detect singular

 localp={}
 localgetArgs=require('Module:Arguments').getArgs
 localyesNo=require('Module:Yesno')

 -- function to determine whether "sub" occurs in "s"
 localfunctionplainFind(s,sub)
 returnmw.ustring.find(s,sub,1,true)
 end

 -- function to count the number of times "pattern" (a regex) occurs in "s"
 localfunctioncountMatches(s,pattern)
 local_,count=mw.ustring.gsub(s,pattern,'')
 returncount
 end

 localsingular=1
 locallikelyPlural=2
 localplural=3

 -- Determine whether a string is singular or plural (i.e., it represents one
 -- item or many)
 -- Arguments:
 -- origArgs[1]: string to process
 -- origArgs.no_comma: if false, use commas to detect plural (default false)
 -- origArgs.parse_links: if false, treat wikilinks as opaque singular objects (default false)
 -- origArgs.any_comma: if true, allow any comma to cause likely plural, including ones between digits (default false)
 -- origArgs.no_and: if false, use existence of "and" to detect plural (default false)
 -- origArgs.parse_number: if true, parse number in argument: if 1, singular; if >1, plural (default false)
 -- Returns:
 -- singular, likelyPlural, or plural (see constants above), or nil for completely unknown
 functionp._main(origArgs)
 origArgs=type(origArgs)=='table'andorigArgsor{}
 localargs={}
 -- canonicalize boolean arguments
 forkey,defaultinpairs({no_comma=false,parse_links=false,any_comma=false,
 no_and=false,parse_number=false})do
 iforigArgs[key]==nilthen
 args[key]=default
 else
 args[key]=yesNo(origArgs[key],default)
 end
 end
 localcheckComma=notargs.no_comma
 localcheckAnd=notargs.no_and
 localrewriteLinks=notargs.parse_links
 localanyComma=args.any_comma
 localparseNumber=args.parse_number
 locals=origArgs[1]-- the input string
 ifnotsthen
 returnnil-- empty input returns nil
 end
 s=tostring(s)
 s=mw.text.decode(s,true)--- replace HTML entities (to avoid spurious semicolons)
 ifplainFind(s,'data-plural="0"')then-- magic data string to return true
 returnsingular
 end
 ifplainFind(s,'data-plural="1"')then-- magic data string to return false
 returnplural
 end
 -- count number of list items
 localnumListItems=countMatches(s,'<%s*li')
 -- if exactly one, then singular, if more than one, then plural
 ifnumListItems==1then
 returnsingular
 end
 ifnumListItems>1then
 returnplural
 end
 -- if "list of" occurs inside of wlink, then it's plural
 ifmw.ustring.find(s:lower(),'%[%[[^%]]*list of[^%]]+%]%]')then
 returnplural
 end
 ifparseNumberthen
 localm=tonumber(mw.ustring.match(s,"^%s*(%d+)"))
 ifmthen
 returnm>1andpluralorsingular
 end
 end
 -- fix for trailing br tags passed through [[template:marriage]]
 s=mw.ustring.gsub(s,'<%s*br[^>]*>%s*(</div>)','%1')
 -- replace all wikilinks with fixed string
 ifrewriteLinksthen
 s=mw.ustring.gsub(s,'%b[]','WIKILINK')
 end
 -- Five conditions: any one of them can make the string a likely plural or plural
 localhasBreak=mw.ustring.find(s,'<%s*br')
 -- For the last 4, evaluate on string stripped of wikimarkup
 localgetPlain=require('Module:Text').Text().getPlain
 s=getPlain(s)
 localhasBullets=countMatches(s,'%*+')>1
 localmultipleQids=mw.ustring.find(s,'Q%d+[%p%s]+Q%d+')-- has multiple QIDs in a row
 ifhasBulletsormultipleQidsthen
 returnplural
 end
 localcommaPattern=anyCommaand'[,;]'or'%D[,;]%D'-- semi-colon similar to comma
 localhasComma=checkCommaandmw.ustring.find(s,commaPattern)
 localhasAnd=checkAndandmw.ustring.find(s,'[,%s]and%s')
 ifhasBreakorhasCommaorhasAndthen
 returnlikelyPlural
 end
 returnsingular
 end

 functionp._pluralize(args)
 args=type(args)=='table'andargsor{}
 localsingularForm=args[3]orargs.singularor""
 localpluralForm=args[4]orargs.pluralor""
 locallikelyForm=args.likelyorpluralForm
 locallink=args[5]orargs.link
 iflinkthen
 link=tostring(link)
 singularForm='[['..link..'|'..singularForm..']]'
 pluralForm='[['..link..'|'..pluralForm..']]'
 likelyForm='[['..link..'|'..likelyForm..']]'
 end
 ifargs[2]then
 returnpluralForm
 end
 localdetect=p._main(args)
 ifdetect==nilthen
 return""-- return blank on complete failure
 end
 ifdetect==singularthen
 returnsingularForm
 elseifdetect==likelyPluralthen
 returnlikelyForm
 else
 returnpluralForm
 end
 end

 functionp.main(frame)
 localargs=getArgs(frame)
 -- For template, return 1 if singular, blank if plural or empty
 localresult=p._main(args)
 ifresult==nilthen
 return1
 end
 returnresult==singularand1or""
 end

 functionp.pluralize(frame)
 localargs=getArgs(frame)
 returnp._pluralize(args)
 end

 returnp