Module:User:Rua/parameters

local export = {}

function export.process(args, params)
	-- Process parameters for specific properties
	local required = {}
	local patterns = {}
	
	for name, param in pairs(params) do
		if param.required then
			required = true
		end
		
		if param.pattern then
			patterns = name
		end
	end
	
	-- Process the arguments
	local args_new = {}
	
	for name, val in pairs(args) do
		-- Does this argument name match a pattern?
		local index = nil
		
		for pattern, pname in pairs(patterns) do
			index = mw.ustring.match(name, pattern)
			
			-- It matches, so store the parameter name and the
			-- numeric index extracted from the argument name.
			if index then
				index = tonumber(index)
				name = pname
				break
			end
		end
		
		local param = params
		
		-- If the argument is not in the list of parameters, trigger an error.
		if not params then
			error("The parameter \"" .. name .. "\" does not exist.")
		end
		
		-- Empty string is equivalent to nil unless allow_empty is true.
		if val == "" and not param.allow_empty then
			val = nil
		end
		
		-- Convert to proper type if necessary.
		if param.type == "boolean" then
			val = not (not val or val == "" or val == "0" or val == "no" or val == "n" or val == "false")
		elseif param.type == "number" then
			val = tonumber(val)
		end
		
		-- Can't use "if val" alone, because val may be a boolean false.
		if val ~= nil then
			-- Mark it as no longer required, as it is present.
			required = nil
			
			-- Store the argument value.
			if param.pattern then
				-- If the parameter has a pattern, then it becomes a list.
				if args_new == nil then
					args_new = {}
				end
				
				args_new = val
			else
				-- If the parameter is an alias of another, store it as the original,
				-- but avoid overwriting it; the original takes precedence.
				if not param.alias_of then
					args_new = val
				elseif args == nil then
					args_new = val
				end
			end
		end
	end
	
	-- The required table should now be empty.
	-- If any entry remains, trigger an error, unless we're in the template namespace.
	if mw.title.getCurrentTitle().nsText ~= "Template" then
		for name, param in pairs(required) do
			error("The parameter \"" .. name .. "\" is required.")
		end
	end
	
	return args_new
end

return export