# 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  

require ('strict');  

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  

-- create the list of known args, regular expressions, and the return string  
local knownargs = {}  
local regexps = {}  
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  

-- loop over the parent args, and make sure they are on the list  
local ignoreblank = isnotempty(args['ignoreblank'])  
local showblankpos = isnotempty(args['showblankpositional'])  
local values = {}  
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 then  
local knownflag = false  
for _, regexp in ipairs(regexps) do  
if mw.ustring.match(tostring(k), regexp) then  
knownflag = true  
break  
end  
end  
if not knownflag and ( showblankpos or isnotempty(v) ) then  
table.insert(values, k .. ' = ' .. clean(v))  
end  
end  
end  

-- add results to the output tables  
local res = {}  
if #values > 0 then  
local unknown_text = args['unknown'] or 'Found _VALUE_, '  

if mw.getCurrentFrame:preprocess( "" ) == "" then  
local preview_text = args['preview']  
if isnotempty(preview_text) then  
preview_text = require('Module:If preview')._warning({preview_text})  
elseif preview_text == nil then  
preview_text = unknown_text  
end  
unknown_text = preview_text  
end  
for _, v in pairs(values) do  
-- Fix odd bug for | = which gets stripped to the empty string and  
-- breaks category links  
if v == '' then v = ' ' end  

-- avoid error with v = 'example%2' ("invalid capture index")  
local r = unknown_text:gsub('_VALUE_', {_VALUE_ = v})  
table.insert(res, r)  
end  
end  

return table.concat(res)  
end  

function p.check  
local args = .args  
local pargs = :getParent.args  
return p._check(args, pargs)  
end  

return p