Module:Category see also

 -- This module implements {{Category see also}}

 localmHatnote=require('Module:Hatnote')

 localp={}

 localfunctionmakeWikitextError(msg)
 returnstring.format(
 '<strong class="error">Error: %s ([[Template:Category see also]])</strong>',
 msg
 )
 end

 -- Gets the length of the sequence seq. Usually this should be done with the #
 -- operator, but we need to work with tables that get their values through an
 -- __index metamethod.
 localfunctiongetSequenceLength(seq)
 locallength=0
 foriinipairs(seq)do
 length=i
 end
 returnlength
 end

 -- Given a table of options, returns a function that formats categories for
 -- those options.
 --
 -- Options:
 -- project - a project code such as "fr" (for the French Wikipedia)
 -- showPrefix - a boolean value for whether to show the "Category:" prefix
 -- (and the project prefix if specified)
 --
 -- This is implemented as a function generator rather than a simple function
 -- so that we can just process the options once, instead of every time we
 -- generate a category.
 localfunctionnewCategoryLinker(options)
 localformatString
 ifoptions.projectthen
 ifoptions.showPrefixthen
 formatString='[[:'..options.project..':Category:%s]]'
 else
 formatString='[[:'..options.project..':Category:%s|%s]]'
 end
 else
 ifoptions.showPrefixthen
 formatString='[[:Category:%s]]'
 else
 formatString='[[:Category:%s|%s]]'
 end
 end
 returnfunction(category)
 localtitle=mw.title.new(category)
 localpageName,display
 ifnottitlethen
 -- category is not a valid title, usually because of invalid
 -- characters like < or [. Raise an error and suppress the stack
 -- level information so that we can catch it and format the error
 -- message as wikitext.
 error(string.format(
 "'%s' is not a valid category name",
 category
 ),0)
 elseiftitle.namespace==14then-- Category namespace
 pageName=title.text
 display=title.text
 else
 pageName=title.prefixedText
 display=category
 end
 -- We can get away with using two arguments even when
 -- options.showDisplay is false, as string.format ignores extra
 -- arguments as long as there is an argument for each flag in the
 -- format string.
 returnformatString:format(pageName,display)
 end
 end

 functionp._main(args)
 localnLinks=getSequenceLength(args)

 ifnLinks<1then
 returnmakeWikitextError('at least one parameter required')
 end

 localmakeCategoryLink=newCategoryLinker{
 project=args.project,
 showPrefix=nLinks==1,
 }

 locallinks={}
 fori,catinipairs(args)do
 localsuccess,categoryLink=pcall(makeCategoryLink,cat)
 ifsuccessthen
 links[i]=categoryLink
 else
 -- If there was an error, then categoryLink is the error message.
 returnmakeWikitextError(categoryLink)
 end
 end

 localformatString
 ifnLinks==1then
 formatString='%s: %s'
 else
 formatString='%s the categories %s'
 end

 -- Don't output a comma before the "and" if we have only two links.
 localconjunction
 ifnLinks==2then
 conjunction=' and '
 else
 conjunction=', and '
 end

 localhatnoteText=formatString:format(
 args.LABELorargs.labelor'See also',
 mw.text.listToText(links,', ',conjunction)
 )
 returnmHatnote._hatnote(hatnoteText,{selfref=true})
 end

 functionp.main(frame)
 localargs=require('Module:Arguments').getArgs(frame,{
 wrappers='Template:Category see also',
 })
 returnp._main(args)
 end

 returnp