check For Unknown Parameters

-- This module may be used to compare the arguments passed to the parent -- with a list of arguments, returning a specified result if an argument is -- not on the list local p = {}  local function trim(s) return s:match('^%s*(.-)%s*$') end  local function isnotempty(s) return s and trim(s) ~= '' end  function p.check (frame) local args = frame.args local pargs = frame:getParent().args local ignoreblank = isnotempty(frame.args['ignoreblank']) local checkpos = isnotempty(frame.args['checkpositional']) local knownargs = {} local unknown = frame.args['unknown'] or 'Found _VALUE_, ' local preview = frame.args['preview']  local res = {} local regexps = {} local comments = {} local commentstr = ''  local ispreview = frame:preprocess( "{{REVISIONID}}" ) == "" and 1 or 0  -- create the list of known args, regular expressions, and the return string for k, v in pairs(args) do if type(k) == 'number' then v = trim(v) knownargs[v] = 1 elseif k:find('^regexp[1-9][0-9]*$') then table.insert(regexps, '^' .. v .. '$') end end if isnotempty(preview) then  preview = '
Warning: ' .. preview .. ' (this message is shown only in preview).
' elseif preview == nil then preview = unknown end if ispreview == 1 then unknown = preview ignoreblank = false end  -- adds one result to the output tables local function addresult(k) if k == '' then -- Fix odd bug for | = which gets stripped to the empty string and -- breaks category links k = ' ' end local r = unknown:gsub('_VALUE_', k) table.insert(res, r) table.insert(comments, '"' .. k .. '"') end  -- loop over the parent args, and make sure they are on the list for k, v in pairs(pargs) do if type(k) == 'string' and knownargs[k] == nil then local knownflag = false for i, regexp in ipairs(regexps) do if mw.ustring.match(k, regexp) then knownflag = true break end end if not knownflag and ( not ignoreblank or isnotempty(v) ) then k = mw.ustring.gsub(k, '[^%w\-_ ]', '?') addresult(k) end elseif checkpos and type(k) == 'number' and knownargs[tostring(k)] == nil and ( not ignoreblank or isnotempty(v) ) then addresult(k) end end  if #comments > 0 then commentstr = '' end  return table.concat(res) .. commentstr end  return p