Module:Arguments: Difference between revisions

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m>Mr. Stradivarius
don't use "if frame == mw.getCurrentFrame()"
m>Mr. Stradivarius
memoize nils, add type checks for frame and options, use string library functions instead of mw.text.trim and mw.ustring.find, define four different tidyVal functions to avoid checking options every time
Line 1: Line 1:
-- This module provides easy processing of arguments passed to Scribunto from #invoke.
-- 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.
-- 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 arguments = {}
local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
-- Generate four different tidyVal functions, so that we don't have to check the options every time we call it.
local function tidyValDefault(key, val)
if type(val) == 'string' then
val = val:match('^%s*(.-)%s*$')
if val == '' then
return nil
else
return val
end
else
return val
end
end
local function tidyValTrimOnly(key, val)
if type(val) == 'string' then
return val:match('^%s*(.-)%s*$')
else
return val
end
end
local function tidyValRemoveBlanksOnly(key, val)
if type(val) == 'string' then
if val:find('%S') then
return val
else
return nil
end
else
return val
end
end
local function tidyValNoChange(key, val)
return val
end


function arguments.getArgs(frame, options)
function arguments.getArgs(frame, options)
options = type(options) == 'table' and options or {}
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
-- 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.
-- 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
local fargs, pargs, luaArgs
if type(frame) == 'table' and type(frame.args) == 'table' and type(frame.getParent) == 'function' then
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
fargs = frame.args
if not options.parentOnly then
pargs = frame:getParent().args
fargs = frame.args
end
if not options.frameOnly then
pargs = frame:getParent().args
end
if options.parentFirst then
fargs, pargs = pargs, fargs
end
else
else
luaArgs = type(frame) == 'table' and frame or {}
luaArgs = frame
end
end


Line 22: Line 76:
setmetatable(args, metatable)
setmetatable(args, metatable)


local function tidyVal(key, val)
-- Generate the tidyVal function. If it has been specified by the user, we use that; if not, we choose one of four functions
-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks.
-- depending on the options chosen. This is so that we don't have to call the options table every time the function is called.
-- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage.
local tidyVal = options.valueFunc
if type(val) == 'string' then
if tidyVal then
if options.trim ~= false then
if type(tidyVal) ~= 'function' then
val = mw.text.trim(val)
error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2)
end
end
if options.removeBlanks == false or mw.ustring.find(val, '%S') then
elseif options.trim ~= false then
return val
if options.removeBlanks ~= false then
end
tidyVal = tidyValDefault
else
else
return val
tidyVal = tidyValTrimOnly
end
end
end
else
 
if options.removeBlanks ~= false then
-- Use a user-generated function to tidy the values if specified.
tidyVal = tidyValRemoveBlanksOnly
local valueFunc = options.valueFunc
if valueFunc then
local valueFuncType = type(valueFunc)
if valueFuncType == 'function' then
tidyVal = valueFunc
else
else
error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)
tidyVal = tidyValNoChange
end
end
end
end
Line 51: Line 100:
-- 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
if metaArgs[key] == nil then
local metaArgsVal = metaArgs[key]
metaArgs[key] = tidyVal(key, val)
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
Line 61: Line 117:


-- Set the order of precedence of the argument tables. If the variables are nil, nothing will be added to the table,
-- 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.
-- which is how we avoid clashes between the frame/parent args and the Lua args.
local argTables = {}
local argTables = {fargs}
if options.frameOnly then
argTables[#argTables + 1] = pargs
table.insert(argTables, fargs)
argTables[#argTables + 1] = luaArgs
elseif options.parentOnly then
table.insert(argTables, pargs)
elseif options.parentFirst then
table.insert(argTables, pargs)
table.insert(argTables, fargs)
else
table.insert(argTables, fargs)
table.insert(argTables, pargs)
end
table.insert(argTables, luaArgs)


--[[
--[[
-- Define metatable behaviour. Arguments are stored in the metaArgs table, and are only fetched from the
-- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the
-- argument tables once. Also, we keep a record in the metatable of when pairs and ipairs have been called,
-- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase
-- so we do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargs
-- performance. Also, we keep a record in the metatable of when pairs and ipairs have been called, so we
-- and pargs if pairs has already been run, as all the arguments will already have been copied over.
-- 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)
metatable.__index = function (t, key)
local val = metaArgs[key]
local val = metaArgs[key]
if val ~= nil then
if val ~= nil then
return val
if val == nilArg then
else
return nil
for i, argTable in ipairs(argTables) do
else
local argTableVal = tidyVal(key, argTable[key])
return val
if argTableVal ~= nil then
end
metaArgs[key] = argTableVal
end
return argTableVal
for _, argTable in ipairs(argTables) do
end
local argTableVal = tidyVal(key, argTable[key])
if argTableVal == nil then
metaArgs[key] = nilArg
else
metaArgs[key] = argTableVal
return argTableVal
end
end
end
end
return nil
end
end


metatable.__newindex = function (t, key, val)
metatable.__newindex = function (t, key, val)
if not options.readOnly and (not options.noOverwrite or args[key] == nil) then
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
metaArgs[key] = val
end
end

Revision as of 13:06, 11 December 2013

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

-- Generate four different tidyVal functions, so that we don't have to check the options every time we call it.

local function tidyValDefault(key, val)
	if type(val) == 'string' then
		val = val:match('^%s*(.-)%s*$')
		if val == '' then
			return nil
		else
			return val
		end
	else
		return val
	end
end

local function tidyValTrimOnly(key, val)
	if type(val) == 'string' then
		return val:match('^%s*(.-)%s*$')
	else
		return val
	end
end

local function tidyValRemoveBlanksOnly(key, val)
	if type(val) == 'string' then
		if val:find('%S') then
			return val
		else
			return nil
		end
	else
		return val
	end
end

local function tidyValNoChange(key, val)
	return val
end

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)

	-- Generate the tidyVal function. If it has been specified by the user, we use that; if not, we choose one of four functions
	-- depending on the options chosen. This is so that we don't have to call the options table every time the function is called.
	local tidyVal = options.valueFunc
	if tidyVal then
		if type(tidyVal) ~= 'function' then
			error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2)
		end
	elseif options.trim ~= false then
		if options.removeBlanks ~= false then
			tidyVal = tidyValDefault
		else
			tidyVal = tidyValTrimOnly
		end
	else
		if options.removeBlanks ~= false then
			tidyVal = tidyValRemoveBlanksOnly
		else
			tidyVal = tidyValNoChange
		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