Module:Parameter validation
local util = {
 	empty = function( s ) 
 		return s == nil  or type( s ) == 'string' and mw.text.trim( s ) == ''   
 	end
 	, 
 	extract_options = function ( frame, optionsPrefix )
 		optionsPrefix = optionsPrefix or 'options' 
 
 		local options, n, more = {}
 		if frame.args['module_options'] then
 			local module_options = mw.loadData( frame.args['module_options'] ) 
 			if type( module_options ) ~= 'table' then return {} end
 			local title = mw.title.getCurrentTitle()
 			local local_ptions = module_options[ title.namespace ] or module_options[ title.nsText ] or {} 
 			for k, v in pairs( local_ptions ) do options[k] = v end
 		end
 		
 		repeat
 			ok, more = pcall( mw.text.jsonDecode, frame.args[optionsPrefix .. ( n or '' )] )
 			if ok and type( more ) == 'table' then
 				for k, v in pairs( more ) do options[k] = v end
 			end
 			n = ( n or 0 ) + 1
 		until not ok
 
 		return options
 	end
 	, 
 	build_namelist = function ( template_name, sp )
 		local res = { template_name }
 		if sp then
 			if type( sp ) == 'string' then sp = { sp } end
 			for _, p in ipairs( sp ) do table.insert( res, template_name .. '/' .. p ) end
 		end
 		return res
 	end
 	,
 	table_empty = function( t ) -- normally, test if next(t) is nil, but for some perverse reason, non-empty tables returned by loadData return nil...
 		if type( t ) ~= 'table' then return true end
 		for a, b in pairs( t ) do return false end
 		return true
 	end
 	,
 }
 
 local function _readTemplateData( templateName ) 
 	local title = mw.title.makeTitle( 0, templateName )  
 	local templateContent = title and title.exists and title:getContent() -- template's raw content
 	local capture =  templateContent and mw.ustring.match( templateContent, '&lt;templatedata%s*&gt;(.*)&lt;/templatedata%s*&gt;' ) -- templatedata as text
 --	capture = capture and mw.ustring.gsub( capture, '&quot;(%d+)&quot;', tonumber ) -- convert &quot;1&quot;: {} to 1: {}. frame.args uses numerical indexes for order-based params.
 	local trailingComma = capture and mw.ustring.find( capture, ',%s*[%]%}]' ) -- look for ,] or ,} : jsonDecode allows it, but it's verbotten in json
 	if capture and not trailingComma then return pcall( mw.text.jsonDecode, capture ) end
 	return false
 end
 
 local function readTemplateData( templateName )
 	if type( templateName ) == 'string' then 
 		templateName = { templateName, templateName .. '/' .. docSubPage }
 	end
 	if type( templateName ) == &quot;table&quot; then
 		for _, name in ipairs( templateName ) do
 			local td, result = _readTemplateData( name ) 
 			if td then return result end
 		end
 	end
 	return nil
 end
 
 
 -- this is the function to be called by other modules. it expects the frame, and then an optional list of subpages, e.g. { &quot;Documentation&quot; }.
 -- if second parameter is nil, only tempalte page will be searched for templatedata.
 function calculateViolations( frame, subpages )
 -- used for parameter type validy test. keyed by TD 'type' string. values are function(val) returning bool.
 	local type_validators = { 
 		['number'] = function( s ) return mw.language.getContentLanguage():parseFormattedNumber( s ) end
 	}
 	function compatible( typ, val )
 		local func = type_validators[typ]
 		return type( func ) ~= 'function' or util.empty( val ) or func( val )
 	end
 	
 	local t_frame = frame:getParent()
 	local t_args, template_name = t_frame.args, t_frame:getTitle()
 	template_name = mw.ustring.gsub( template_name, '/sandbox', '', 1 )
 	local td_source = util.build_namelist( template_name, subpages )
 	if frame.args['td_source'] then
 		table.insert(td_source, frame.args['td_source'])
 	end
 
 	local templatedata = readTemplateData( td_source )
 	local td_params = templatedata and templatedata.params
 	local all_aliases, all_series = {}, {}
 
 	if not td_params then return { ['no-templatedata'] = { [''] = '' } } end
 	-- from this point on, we know templatedata is valid.
 
 	local res = {} -- before returning to caller, we'll prune empty tables
 
 	-- allow for aliases
 	for x, p in pairs( td_params ) do for y, alias in ipairs( p.aliases or {} ) do
 		p['primary'] = x
 		td_params[x] = p
 		all_aliases[alias] = p
 		if tonumber(alias) then all_aliases[tonumber(alias)] = p end
 	end end
 
 	-- handle undeclared and deprecated
 	local already_seen = {}
 	local series = frame.args['series']
 	for p_name, value in pairs( t_args ) do
 		local tp_param, noval, numeric, table_name = td_params[p_name] or all_aliases[p_name], util.empty( value ), tonumber( p_name )
 		local hasval = not noval
 
 		if not tp_param and series then -- 2nd chance. check to see if series
 			for s_name, p in pairs(td_params) do 
 				if mw.ustring.match( p_name, '^' .. s_name .. '%d+' .. '$') then 
 					-- mw.log('found p_name '.. p_name .. '  s_name:' .. s_name, ' p is:', p) debugging series support
 					tp_param = p 
 				end -- don't bother breaking. td always correct.
 			end 				
 		end
 
 		if not tp_param then -- not in TD: this is called undeclared
 			-- calculate the relevant table for this undeclared parameter, based on parameter and value types
 			table_name = 
 				noval and numeric and 'empty-undeclared-numeric' or
 				noval and not numeric and 'empty-undeclared' or
 				hasval and numeric and 'undeclared-numeric' or
 				'undeclared' -- tzvototi nishar.
 		else -- in td: test for deprecation and mistype. if deprecated, no further tests
 			table_name = tp_param.deprecated and hasval and 'deprecated' 
 				or tp_param.deprecated and noval and 'empty-deprecated' 
 				or not compatible( tp_param.type, value ) and 'incompatible'
 				or not series and already_seen[tp_param] and hasval and 'duplicate'
 
 			if hasval and table_name ~= 'duplicate' then
 				already_seen[tp_param] = p_name
 			end
 		end
 		
 		-- report it.
 		if table_name then
 			res[table_name] = res[table_name] or {}
 			if table_name == 'duplicate' then
 				local primary_param = tp_param['primary']
 				local primaryData = res[table_name][primary_param]
 				if not primaryData then
 					primaryData = {}
 					table.insert(primaryData, already_seen[tp_param])
 				end
 				table.insert(primaryData, p_name)
 				res[table_name][primary_param] = primaryData
 			else
 				res[table_name][p_name] = value
 			end
 		end
 	end
 
 	-- check for empty/missing parameters declared &quot;required&quot; 
 	for p_name, param in pairs( td_params ) do 
 		if param.required and util.empty( t_args[p_name] ) then
 			local is_alias
 			for _, alias in ipairs( param.aliases or {} ) do is_alias = is_alias or not util.empty( t_args[alias] ) end
 			if not is_alias then
 				res['empty-required'] = res['empty-required'] or {} 
 				res['empty-required'][p_name] = '' 
 			end
 		end
 	end
 	
 	mw.logObject(res)
 	
 	return res
 end
 
 -- wraps report in hidden frame
 function wrapReport(report, template_name, options)
 	mw.logObject(report)
 	if util.empty( report ) then return '' end
 	local naked = mw.title.new( template_name )['text']
 	naked = mw.ustring.gsub(naked, 'Infobox', 'infobox', 1)
 	
 	report = ( options['wrapper-prefix'] or &quot;&lt;div class = 'paramvalidator-wrapper'&gt;&lt;span class='paramvalidator-error'&gt;&quot; )
 			.. report
 			.. ( options['wrapper-suffix'] or &quot;&lt;/span&gt;&lt;/div&gt;&quot; )
 	
 	report = mw.ustring.gsub( report, 'tname_naked', naked )
 	report = mw.ustring.gsub( report, 'templatename', template_name )
 
 	return report
 end
 
 -- this is the &quot;user&quot; version, called with {{#invoke:}} returns a string, as defined by the options parameter
 function validateParams( frame )
 	local options, report, template_name = util.extract_options( frame ), '', frame:getParent():getTitle()
 
 	local ignore = function( p_name )
 		for _, pattern in ipairs( options['ignore'] or {} ) do
 			if mw.ustring.match( p_name, '^' .. pattern .. '$' ) then return true end
 		end
 		return false
 	end
 
 	local replace_macros = function( error_type, s, param_names )
 		function concat_and_escape( t , sep )
 			sep = sep or ', '
 			local s = table.concat( t, sep )
 			return ( mw.ustring.gsub( s, '%%', '%%%%' ) )
 		end
 		
 		if s and ( type( param_names ) == 'table' ) then
 			local k_ar, kv_ar = {}, {}
 			for k, v in pairs( param_names ) do
 				table.insert( k_ar, k )
 				if type(v) == 'table' then
 					v = table.concat(v, ', ')
 				end
 					
 				if error_type == 'duplicate' then
 					table.insert( kv_ar, v)
 				else
 					table.insert( kv_ar, k .. ': ' .. v)
 				end
 			end
 			
 			s = mw.ustring.gsub( s, 'paramname', concat_and_escape( k_ar ) )
 			s = mw.ustring.gsub( s, 'paramandvalue', concat_and_escape( kv_ar, ' AND ' ) )
 
 			if mw.getCurrentFrame():preprocess( &quot;{{REVISIONID}}&quot; ) ~= &quot;&quot; then
 				s = mw.ustring.gsub( s, &quot;&lt;div.*&lt;%/div&gt;&quot;, &quot;&quot;, 1 )
 			end
 		end
 		return s
 	end
 
 	local report_params = function( key, param_names )
 		local res = replace_macros( key, options[key], param_names )
 		res = frame:preprocess(res or '')
 		report = report ..  ( res or '' )
 		return res
 	end
 
 	-- no option no work.
 	if util.table_empty( options ) then return '' end
 
 	-- get the errors.
 	local violations = calculateViolations( frame, options['doc-subpage'] )
 	-- special request of bora: use skip_empty_numeric
 	if violations['empty-undeclared-numeric'] then 
 		for i = 1, tonumber( options['skip-empty-numeric'] ) or 0 do 
 			violations['empty-undeclared-numeric'][i] = nil 
 		end
 	end
 	
 	-- handle ignore list, and prune empty violations - in that order!
 	local offenders = 0
 	for name, tab in pairs( violations ) do 
 		-- remove ignored parameters from all violations
 		for pname in pairs( tab ) do if ignore( pname ) then tab[pname] = nil end end
 		-- prune empty violations
 		if util.table_empty( tab ) then violations[name] = nil end
 	-- WORK IS DONE. report the errors.
 	-- if report then count it.
 		if violations[name] and report_params( name, tab ) then offenders = offenders + 1 end 
 	end
 
 	if offenders &gt; 1 then report_params( 'multiple' ) end
 	if offenders ~= 0 then report_params( 'any' ) end -- could have tested for empty( report ), but since we count them anyway...
 	return wrapReport(report, template_name, options)
 end
 
 return {
 	['validateparams'] = validateParams,
 	['calculateViolations'] = calculateViolations,
 	['wrapReport'] = wrapReport