--[[  --                                                                            -- --                            NAMESPACE DETECT                                -- --                                                                            -- -- This module implements the  template in Lua, with a    -- -- few improvements: all namespaces and all namespace aliases are supported,  -- -- and namespace names are detected automatically for the local wiki. The     -- -- module can also use the corresponding subject namespace value if it is     -- -- used on a talk page. Parameter names can be configured for different wikis -- -- by altering the values in the "cfg" table in                               -- -- মডিউল:বিষয়শ্রেণী পরিচালনাকারী/রূপরেখা.                                            -- --                                                                            --  --]]  local data = mw.loadData('মডিউল:নামস্থান শনাক্তকরণ/উপাত্ত') local argKeys = data.argKeys local cfg = data.cfg local mappings = data.mappings  local yesno = require('মডিউল:Yesno') local mArguments -- Lazily initialise Module:Arguments local mTableTools -- Lazily initilalise Module:TableTools local ustringLower = mw.ustring.lower  local p = {}  local function fetchValue(t1, t2) 	-- Fetches a value from the table t1 for the first key in array t2 where 	-- a non-nil value of t1 exists. 	for i, key in ipairs(t2) do 		local value = t1[key] 		if value ~= nil then 			return value 		end 	end 	return nil end  local function equalsArrayValue(t, value) 	-- Returns true if value equals a value in the array t. Otherwise 	-- returns false. 	for i, arrayValue in ipairs(t) do 		if value == arrayValue then 			return true 		end 	end 	return false end  function p.getPageObject(page) 	-- Get the page object, passing the function through pcall in case of 	-- errors, e.g. being over the expensive function count limit. 	if page then 		local success, pageObject = pcall(mw.title.new, page) 		if success then 			return pageObject 		else 			return nil 		end 	else 		return mw.title.getCurrentTitle() 	end end  -- Provided for backward compatibility with other modules function p.getParamMappings() 	return mappings end  local function getNamespace(args) 	-- This function gets the namespace name from the page object. 	local page = fetchValue(args, argKeys.demopage) 	if page ==  then 		page = nil 	end 	local demospace = fetchValue(args, argKeys.demospace) 	if demospace ==  then 		demospace = nil 	end 	local subjectns = fetchValue(args, argKeys.subjectns) 	local ret 	if demospace then 		-- Handle "demospace = main" properly. 		if equalsArrayValue(argKeys.main, ustringLower(demospace)) then 			ret = mw.site.namespaces[0].name 		else 			ret = demospace 		end 	else 		local pageObject = p.getPageObject(page) 		if pageObject then 			if pageObject.isTalkPage then 				-- Get the subject namespace if the option is set, 				-- otherwise use "talk". 				if yesno(subjectns) then 					ret = mw.site.namespaces[pageObject.namespace].subject.name 				else 					ret = 'talk' 				end 			else 				ret = pageObject.nsText 			end 		else 			return nil -- return nil if the page object doesn't exist. 		end 	end 	ret = ret:gsub('_', ' ') 	return ustringLower(ret) end  function p._main(args) 	-- Check the parameters stored in the mappings table for any matches. 	local namespace = getNamespace(args) or 'other' -- "other" avoids nil table keys 	local params = mappings[namespace] or {} 	local ret = fetchValue(args, params) 	--[[ 	-- If there were no matches, return parameters for other namespaces. 	-- This happens if there was no text specified for the namespace that 	-- was detected or if the demospace parameter is not a valid 	-- namespace. Note that the parameter for the detected namespace must be 	-- completely absent for this to happen, not merely blank. 	--]] 	if ret == nil then 		ret = fetchValue(args, argKeys.other) 	end 	return ret end  function p.main(frame) 	mArguments = require('মডিউল:Arguments') 	local args = mArguments.getArgs(frame, {removeBlanks = false}) 	local ret = p._main(args) 	return ret or '' end  function p.table(frame) 	--[[ 	-- Create a wikitable of all subject namespace parameters, for 	-- documentation purposes. The talk parameter is optional, in case it 	-- needs to be excluded in the documentation. 	--]] 	 	-- Load modules and initialise variables. 	mTableTools = require('মডিউল:টেবিল সরঞ্জাম') 	local namespaces = mw.site.namespaces 	local cfg = data.cfg 	local useTalk = type(frame) == 'table'  		and type(frame.args) == 'table'  		and yesno(frame.args.talk) -- Whether to use the talk parameter. 	 	-- Get the header names. 	local function checkValue(value, default) 		if type(value) == 'string' then 			return value 		else 			return default 		end 	end 	local nsHeader = checkValue(cfg.wikitableNamespaceHeader, 'Namespace') 	local aliasesHeader = checkValue(cfg.wikitableAliasesHeader, 'Aliases')  	-- Put the namespaces in order. 	local mappingsOrdered = {} 	for nsname, params in pairs(mappings) do 		if useTalk or nsname ~= 'talk' then 			local nsid = namespaces[nsname].id 			-- Add 1, as the array must start with 1; nsid 0 would be lost otherwise. 			nsid = nsid + 1  			mappingsOrdered[nsid] = params 		end 	end 	mappingsOrdered = mTableTools.compressSparseArray(mappingsOrdered)  	-- Build the table. 	local ret = '{| class="wikitable"' 		.. '\n|-' 		.. '\n! ' .. nsHeader 		.. '\n! ' .. aliasesHeader 	for i, params in ipairs(mappingsOrdered) do 		for j, param in ipairs(params) do 			if j == 1 then 				ret = ret .. '\n|-' 					.. '\n| ' .. param .. '' 					.. '\n| ' 			elseif j == 2 then 				ret = ret .. '' .. param .. '' 			else 				ret = ret .. ', ' .. param .. '' 			end 		end 	end 	ret = ret .. '\n|-' 		.. '\n|}' 	return ret end  return p