Module:Check for conflicting parameters

 localp={}

 localfunctiontrim(s)
 returns:match('^%s*(.-)%s*$')
 end

 localfunctionisnotempty(s)
 returnsands:match('%S')
 end

 functionp.check(frame)
 localargs=frame.args
 localpargs=frame:getParent().args
 localchecknested=isnotempty(args['nested'])
 localdelimiter=isnotempty(args['delimiter'])andargs['delimiter']or';'
 localargpairs={}

 fork,vinpairs(args)do
 iftype(k)=='number'then
 localplist=mw.text.split(v,delimiter)
 localpfound={}
 localcount=0
 forii,vvinipairs(plist)do
 vv=trim(vv)
 ifchecknestedandpargs[vv]orisnotempty(pargs[vv])then
 count=count+1
 table.insert(pfound,vv)
 end
 end
 ifcount>1then
 table.insert(argpairs,pfound)
 end
 end
 end

 localwarnmsg={}
 localres=''
 localcat=''
 ifargs['cat']andmw.ustring.match(args['cat'],'^[Cc][Aa][Tt][Ee][Gg][Oo][Rr][Yy]:')then
 cat=args['cat']
 end
 localtemplate=args['template']and' in '..args['template']or''
 if#argpairs>0then
 fori,vinipairs(argpairs)do
 table.insert(
 warnmsg,
 mw.ustring.format(
 'Using more than one of the following parameters%s: <code>%s</code>.',
 template,
 table.concat(v,'</code>, <code>')
 )
 )
 ifcat~=''then
 res=res..'[['..cat..'|'..(v[1]==''and' 'or'')..v[1]..']]'
 end
 end
 end

 if#warnmsg>0then
 res=require('Module:If preview')._warning({
 table.concat(warnmsg,'<br>')
 })..res
 end

 returnres
 end

 returnp