Module:ParameterCount

 -- This module produces a count of all the arguments passed to it.

 localyesno=require('Module:Yesno')

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

 -- Test whether a string is blank
 localfunctionisBlank(s)
 returnnots:find('%S')
 end

 -- Tests whether a string is a valid positional key, and if so, returns it. If
 -- the key is invalid, this returns nil.
 localfunctionisPositionalKey(s)
 s=trim(s)
 ifs:find('^[1-9][0-9]*$')then
 returntonumber(s)
 end
 end

 -- Return the count of all arguments for which testFunc returns a truthy value.
 localfunctioncount(args,testFunc)
 localret=0
 forkey,valinpairs(args)do
 iftestFunc(key,val)then
 ret=ret+1
 end
 end
 returnret
 end

 -- Check shared arguments and get the parent argument count.
 localfunctionmain(frame,testFunc)
 localblankifiedTestFunc
 ifyesno(frame.args.checkblanks)~=falsethen
 -- Extend the test function to check for blanks as well.
 blankifiedTestFunc=function(key,val)
 ifnotisBlank(val)then
 returntestFunc(key,val)
 end
 end
 else
 blankifiedTestFunc=testFunc
 end
 returncount(frame:getParent().args,blankifiedTestFunc)
 end

 return{
 -- Called with {{#invoke:ParameterCount|all}}
 -- All specified parameters are counted, even those not supported by the
 -- template.
 all=function(frame)
 returnmain(frame,function()returntrueend)
 end,

 -- Called with {{#invoke:ParameterCount|main}}
 -- Users can specify a list of parameters to check, and a list of Lua
 -- Ustring patterns to check each parameter against.
 main=function(frame)
 localargs=frame.args
 localkeys,patterns={},{}

 -- Get key list
 fori,keyinipairs(args)do
 localpositionalKey=isPositionalKey(key)
 ifpositionalKeythen
 keys[positionalKey]=true
 else
 keys[trim(key)]=true
 end
 end

 -- Get patterns
 do
 localfunctiongetPattern(i)
 localpattern=args['pattern'..tostring(i)]
 ifpatternandpattern~=''then
 returnpattern
 end
 end
 locali=1
 localpattern=getPattern(i)
 whilepatterndo
 patterns[i]=pattern
 i=i+1
 pattern=getPattern(i)
 end
 end

 -- Construct the test function
 localtestFunc=function(key,val)
 ifkeys[key]then
 returntrue
 end
 fori,patterninipairs(patterns)do
 ifmw.ustring.find(tostring(key),pattern)then
 returntrue
 end
 end
 returnfalse
 end

 returnmain(frame,testFunc)
 end
 }