Difference between revisions of "Module:Arguments/sandbox"

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blackwiki>Mr. Stradivarius
(start at replacing argTables - still need to convert mergeArgs though)
blackwiki>Mr. Stradivarius
(partially revert back to the argTables code, with a few improvements - code without argTables always seems to turn ugly)
Line 29: Line 29:
 
end
 
end
 
else
 
else
luaArgs = type(frame) == 'table' and frame or {}
+
luaArgs = frame
 
end
 
end
  
Line 67: Line 67:
 
-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
 
-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
 
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
 
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
 +
-- We are also memoizing nil values, but those values can be overwritten.
 
for _, t in ipairs(tables) do
 
for _, t in ipairs(tables) do
 
for key, val in iterator(t) do
 
for key, val in iterator(t) do
Line 82: Line 83:
 
end
 
end
  
local function getValAndMemoize(t, key)
+
-- Set the order of precedence of the argument tables. If the variables are nil, nothing will be added to the table,
-- Gets a value from an argument table and memoizes it in metaArgs.
+
-- which is how we avoid clashes between the frame/parent args and the Lua args.
if t then
+
local argTables = {fargs}
local tidiedVal = tidyVal(key, t[key])
+
argTables[#argTables + 1] = pargs
if tidiedVal == nil then
+
argTables[#argTables + 1] = luaArgs
metaArgs[key] = nilArg
 
else
 
metaArgs[key] = tidiedVal
 
return tidiedVal
 
end
 
end
 
return nil
 
end
 
  
 
--[[
 
--[[
Line 113: Line 106:
 
end
 
end
 
end
 
end
+
for _, argTable in ipairs(argTables) do
local fargsVal = getValAndMemoize(fargs, key)
+
local argTableVal = tidyVal(key, argTable[key])
if fargsVal ~= nil then
+
if argTableVal == nil then
return fargsVal
+
metaArgs[key] = nilArg
end
+
else
local pargsVal = getValAndMemoize(pargs, key)
+
metaArgs[key] = argTableVal
if pargsVal ~= nil then
+
return argTableVal
return pargsVal
+
end
end
 
local luaArgsVal = getValAndMemoize(luaArgs, key)
 
if luaArgsVal ~= nil then
 
return luaArgsVal
 
 
end
 
end
 
return nil
 
return nil

Revision as of 11:50, 11 December 2013

Documentation for this module may be created at Module:Arguments/sandbox/doc

-- This module provides easy processing of arguments passed to Scribunto from #invoke.
-- It is intended for use by other Lua modules, and should not be called from #invoke directly.

local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType

local arguments = {}

local nilArg = {} -- Used for memoizing nil arguments in metaArgs.

function arguments.getArgs(frame, options)
	checkType('getArgs', 1, frame, 'table', true)
	checkType('getArgs', 2, options, 'table', true)
	frame = frame or {}
	options = options or {}

	-- Get the arguments from the frame object if available. If the frame object is not available, we are being called
	-- from another Lua module or from the debug console, so put the args in a special table so we can differentiate them.
	local fargs, pargs, luaArgs
	if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
		if not options.parentOnly then
			fargs = frame.args
		end
		if not options.frameOnly then
			pargs = frame:getParent().args
		end
		if options.parentFirst then
			fargs, pargs = pargs, fargs
		end
	else
		luaArgs = frame
	end

	-- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments.
	-- The metatable connects the two together.
	local args, metaArgs, metatable = {}, {}, {}
	setmetatable(args, metatable)

	local function tidyVal(key, val)
		-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks.
		-- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage.
		if type(val) == 'string' then
			if options.trim ~= false then
				val = val:match('^%s*(.-)%s*$')
			end
			if options.removeBlanks == false or val:find('%S') then
				return val
			end
		else
			return val
		end
		return nil
	end

	-- Use a user-generated function to tidy the values if specified.
	local valueFunc = options.valueFunc
	if valueFunc then
		local valueFuncType = type(valueFunc)
		if valueFuncType == 'function' then
			tidyVal = valueFunc
		else
			error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)
		end
	end

	local function mergeArgs(iterator, tables)
		-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
		-- If a value is already present it is not overwritten; tables listed earlier have precendence.
		-- We are also memoizing nil values, but those values can be overwritten.
		for _, t in ipairs(tables) do
			for key, val in iterator(t) do
				local metaArgsVal = metaArgs[key]
				if metaArgsVal == nil or metaArgsVal == nilArg then
					local tidiedVal = tidyVal(key, val)
					if tidiedVal == nil then
						metaArgs[key] = nilArg
					else
						metaArgs[key] = tidiedVal
					end
				end
			end
		end
	end

	-- Set the order of precedence of the argument tables. If the variables are nil, nothing will be added to the table,
	-- which is how we avoid clashes between the frame/parent args and the Lua args.	
	local argTables = {fargs}
	argTables[#argTables + 1] = pargs
	argTables[#argTables + 1] = luaArgs

	--[[
	-- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the
	-- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase
	-- performance. Also, we keep a record in the metatable of when pairs and ipairs have been called, so we
	-- do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargs and
	-- pargs if pairs has already been run, as all the arguments will already have been copied over.
	--]]

	metatable.__index = function (t, key)
		local val = metaArgs[key]
		if val ~= nil then
			if val == nilArg then
				return nil
			else
				return val
			end
		end
		for _, argTable in ipairs(argTables) do
			local argTableVal = tidyVal(key, argTable[key])
			if argTableVal == nil then
				metaArgs[key] = nilArg
			else
				metaArgs[key] = argTableVal
				return argTableVal
			end
		end
		return nil
	end

	metatable.__newindex = function (t, key, val)
		if options.readOnly then
			error('could not write to argument table key "' .. tostring(key) .. '"; the table is read-only', 2)
		elseif options.noOverwrite and args[key] ~= nil then
			error('could not write to argument table key "' .. tostring(key) .. '"; overwriting existing arguments is not permitted', 2)
		elseif val == nil then
			metaArgs[key] = nilArg -- Memoize nils.
		else
			metaArgs[key] = val
		end
	end

	metatable.__pairs = function ()
		if not metatable.donePairs then
			mergeArgs(pairs, argTables)
			metatable.donePairs = true
			metatable.doneIpairs = true
		end
		return pairs(metaArgs)
	end

	metatable.__ipairs = function ()
		if not metatable.doneIpairs then
			mergeArgs(ipairs, argTables)
			metatable.doneIpairs = true
		end
		return ipairs(metaArgs)
	end

	return args
end

return arguments