Module: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*$') end local function isnotempty(s) return s and s:match('%S') end local function clean(text) -- Return text cleaned for display and truncated if too long. -- Strip markers are replaced with dummy text representing the original wikitext. local pos, truncated local function truncate(text) if truncated then return '' end if mw.ustring.len(text) > 25 then truncated = true text = mw.ustring.sub(text, 1, 25) .. '...'		end return mw.text.nowiki(text) end local parts = {} for before, tag, remainder in text:gmatch('([^\127]*)\127[^\127]*%-(%l+)%-[^\127]*\127') do		pos = remainder table.insert(parts, truncate(before) .. '&lt;' .. tag .. '&gt;...&lt;/' .. tag .. '&gt;') end table.insert(parts, truncate(text:sub(pos or 1))) return table.concat(parts) end function p._check(args, pargs) if type(args) ~= "table" or type(pargs) ~= "table" then -- TODO: error handling return end local ignoreblank = isnotempty(args['ignoreblank']) local showblankpos = isnotempty(args['showblankpositional']) local knownargs = {} local unknown = args['unknown'] or 'Found _VALUE_, ' local preview = args['preview'] local values = {} local res = {} local regexps = {} -- create the list of known args, regular expressions, and the return string for k, v in pairs(args) do		if type(k) == 'number' then v = trim(v) knownargs[v] = 1 elseif k:find('^regexp[1-9][0-9]*$') 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 -- 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 _, 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 table.insert(values, clean(k)) end elseif type(k) == 'number' and knownargs[tostring(k)] == nil and ( showblankpos or isnotempty(v) ) then table.insert(values, k .. ' = ' .. clean(v)) end end -- add results to the output tables if #values > 0 then if mw.getCurrentFrame:preprocess( "" ) == "" then unknown = preview end for _, v in pairs(values) do			if v == '' then -- Fix odd bug for | = which gets stripped to the empty string and -- breaks category links v = ' ' end -- avoid error with v = 'example%2' ("invalid capture index") local r = unknown:gsub('_VALUE_', {_VALUE_ = v}) table.insert(res, r)		end end return table.concat(res) end function p.check(frame) local args = frame.args local pargs = frame:getParent.args return p._check(args, pargs) end return p