Difference between revisions of "Module:Arguments"

From Timelines
Jump to: navigation, search
(create argument-processing module)
 
m (Changed protection level of Module:Arguments: used in the mediawiki interface ex: MediaWiki:Watchlist-details ([Edit=Allow only administrators] (indefinite) [Move=Allow only administrators] (indefinite)))
 
(20 intermediate revisions by 3 users not shown)
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.
  
local function getArguments(frame, options)
+
local libraryUtil = require('libraryUtil')
options = type(options) == 'table' and options or {}
+
local checkType = libraryUtil.checkType
  
local fargs, pargs
+
local arguments = {}
if frame == mw.getCurrentFrame() then
+
 
fargs = frame.args
+
-- Generate four different tidyVal functions, so that we don't have to check the
pargs = frame:getParent().args
+
-- 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
 
else
fargs = type(frame) == 'table' and frame or {}
+
return val
pargs = {}
 
 
end
 
end
 +
end
  
local args, metaArgs, metatable = {}, {}, {}
+
local function tidyValRemoveBlanksOnly(key, val)
setmetatable(args, metatable)
+
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
 +
 
 +
local function matchesTitle(given, title)
 +
local tp = type( given )
 +
return (tp == 'string' or tp == 'number') and mw.title.new( given ).prefixedText == title
 +
end
 +
 
 +
local translate_mt = { __index = function(t, k) return k end }
 +
 
 +
function arguments.getArgs(frame, options)
 +
checkType('getArgs', 1, frame, 'table', true)
 +
checkType('getArgs', 2, options, 'table', true)
 +
frame = frame or {}
 +
options = options or {}
  
local function tidyVal(key, val)
+
--[[
-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks.
+
-- Set up argument translation.
-- 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
+
options.translate = options.translate or {}
if options.trim ~= false then
+
if getmetatable(options.translate) == nil then
val = mw.text.trim(val)
+
setmetatable(options.translate, translate_mt)
 +
end
 +
if options.backtranslate == nil then
 +
options.backtranslate = {}
 +
for k,v in pairs(options.translate) do
 +
options.backtranslate[v] = k
 +
end
 +
end
 +
if options.backtranslate and getmetatable(options.backtranslate) == nil then
 +
setmetatable(options.backtranslate, {
 +
__index = function(t, k)
 +
if options.translate[k] ~= k then
 +
return nil
 +
else
 +
return k
 +
end
 
end
 
end
if options.removeBlanks == false or mw.ustring.find(val, '%S') then
+
})
return val
+
end
 +
 
 +
--[[
 +
-- Get the argument tables. If we were passed a valid frame object, get the
 +
-- frame arguments (fargs) and the parent frame arguments (pargs), depending
 +
-- on the options set and on the parent frame's availability. If we weren't
 +
-- passed a valid frame object, we are being called from another Lua module
 +
-- or from the debug console, so assume that we were passed a table of args
 +
-- directly, and assign it to a new variable (luaArgs).
 +
--]]
 +
local fargs, pargs, luaArgs
 +
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
 +
if options.wrappers then
 +
--[[
 +
-- The wrappers option makes Module:Arguments look up arguments in
 +
-- either the frame argument table or the parent argument table, but
 +
-- not both. This means that users can use either the #invoke syntax
 +
-- or a wrapper template without the loss of performance associated
 +
-- with looking arguments up in both the frame and the parent frame.
 +
-- Module:Arguments will look up arguments in the parent frame
 +
-- if it finds the parent frame's title in options.wrapper;
 +
-- otherwise it will look up arguments in the frame object passed
 +
-- to getArgs.
 +
--]]
 +
local parent = frame:getParent()
 +
if not parent then
 +
fargs = frame.args
 +
else
 +
local title = parent:getTitle():gsub('/sandbox$', '')
 +
local found = false
 +
if matchesTitle(options.wrappers, title) then
 +
found = true
 +
elseif type(options.wrappers) == 'table' then
 +
for _,v in pairs(options.wrappers) do
 +
if matchesTitle(v, title) then
 +
found = true
 +
break
 +
end
 +
end
 +
end
 +
 
 +
-- We test for false specifically here so that nil (the default) acts like true.
 +
if found or options.frameOnly == false then
 +
pargs = parent.args
 +
end
 +
if not found or options.parentOnly == false then
 +
fargs = frame.args
 +
end
 
end
 
end
 
else
 
else
return val
+
-- options.wrapper isn't set, so check the other options.
 +
if not options.parentOnly then
 +
fargs = frame.args
 +
end
 +
if not options.frameOnly then
 +
local parent = frame:getParent()
 +
pargs = parent and parent.args or nil
 +
end
 +
end
 +
if options.parentFirst then
 +
fargs, pargs = pargs, fargs
 
end
 
end
 +
else
 +
luaArgs = frame
 
end
 
end
  
local valueFunc = options.valueFunc
+
-- Set the order of precedence of the argument tables. If the variables are
if valueFunc then
+
-- nil, nothing will be added to the table, which is how we avoid clashes
local valueFuncType = type(valueFunc)
+
-- between the frame/parent args and the Lua args.
if valueFuncType == 'function' then
+
local argTables = {fargs}
tidyVal = valueFunc
+
argTables[#argTables + 1] = pargs
 +
argTables[#argTables + 1] = luaArgs
 +
 
 +
--[[
 +
-- 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
 
else
error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)
+
tidyVal = tidyValNoChange
 
end
 
end
 
end
 
end
  
local function mergeArgs(iterator, ...)
+
--[[
-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
+
-- Set up the args, metaArgs and nilArgs tables. args will be the one
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
+
-- accessed from functions, and metaArgs will hold the actual arguments. Nil
local tables = {...}
+
-- arguments are memoized in nilArgs, and the metatable connects all of them
 +
-- together.
 +
--]]
 +
local args, metaArgs, nilArgs, metatable = {}, {}, {}, {}
 +
setmetatable(args, metatable)
 +
 
 +
local function mergeArgs(tables)
 +
--[[
 +
-- Accepts multiple tables as input and merges their keys and values
 +
-- into one table. If a value is already present it is not overwritten;
 +
-- tables listed earlier have precedence. We are also memoizing nil
 +
-- values, which can be overwritten if they are 's' (soft).
 +
--]]
 
for _, t in ipairs(tables) do
 
for _, t in ipairs(tables) do
for key, val in iterator(t) do
+
for key, val in pairs(t) do
if metaArgs[key] == nil then
+
if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
metaArgs[key] = tidyVal(key, val)
+
local tidiedVal = tidyVal(key, val)
 +
if tidiedVal == nil then
 +
nilArgs[key] = 's'
 +
else
 +
metaArgs[key] = tidiedVal
 +
end
 
end
 
end
 
end
 
end
Line 54: Line 218:
 
end
 
end
  
local firstArgs, secondArgs = fargs, pargs
+
--[[
if options.parentFirst then
+
-- Define metatable behaviour. Arguments are memoized in the metaArgs table,
firstArgs, secondArgs = pargs, fargs
+
-- and are only fetched from the argument tables once. Fetching arguments
end
+
-- from the argument tables is the most resource-intensive step in this
 +
-- module, so we try and avoid it where possible. For this reason, nil
 +
-- arguments are also memoized, in the nilArgs table. 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 the argument tables 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)
 +
--[[
 +
-- Fetches an argument when the args table is indexed. First we check
 +
-- to see if the value is memoized, and if not we try and fetch it from
 +
-- the argument tables. When we check memoization, we need to check
 +
-- metaArgs before nilArgs, as both can be non-nil at the same time.
 +
-- If the argument is not present in metaArgs, we also check whether
 +
-- pairs has been run yet. If pairs has already been run, we return nil.
 +
-- This is because all the arguments will have already been copied into
 +
-- metaArgs by the mergeArgs function, meaning that any other arguments
 +
-- must be nil.
 +
--]]
 +
if type(key) == 'string' then
 +
key = options.translate[key]
 +
end
 
local val = metaArgs[key]
 
local val = metaArgs[key]
 
if val ~= nil then
 
if val ~= nil then
 
return val
 
return val
else
+
elseif metatable.donePairs or nilArgs[key] then
local firstVal = tidyVal(key, firstArgs[key])
+
return nil
if firstVal ~= nil then
+
end
return firstVal
+
for _, argTable in ipairs(argTables) do
else
+
local argTableVal = tidyVal(key, argTable[key])
return tidyVal(key, secondArgs[key])
+
if argTableVal ~= nil then
 +
metaArgs[key] = argTableVal
 +
return argTableVal
 
end
 
end
 
end
 
end
 +
nilArgs[key] = 'h'
 +
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 metaArgs[key] == nil) then
+
-- This function is called when a module tries to add a new value to the
 +
-- args table, or tries to change an existing value.
 +
if type(key) == 'string' then
 +
key = options.translate[key]
 +
end
 +
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
 +
--[[
 +
-- If the argument is to be overwritten with nil, we need to erase
 +
-- the value in metaArgs, so that __index, __pairs and __ipairs do
 +
-- not use a previous existing value, if present; and we also need
 +
-- to memoize the nil in nilArgs, so that the value isn't looked
 +
-- up in the argument tables if it is accessed again.
 +
--]]
 +
metaArgs[key] = nil
 +
nilArgs[key] = 'h'
 +
else
 
metaArgs[key] = val
 
metaArgs[key] = val
 +
end
 +
end
 +
 +
local function translatenext(invariant)
 +
local k, v = next(invariant.t, invariant.k)
 +
invariant.k = k
 +
if k == nil then
 +
return nil
 +
elseif type(k) ~= 'string' or not options.backtranslate then
 +
return k, v
 +
else
 +
local backtranslate = options.backtranslate[k]
 +
if backtranslate == nil then
 +
-- Skip this one. This is a tail call, so this won't cause stack overflow
 +
return translatenext(invariant)
 +
else
 +
return backtranslate, v
 +
end
 
end
 
end
 
end
 
end
  
 
metatable.__pairs = function ()
 
metatable.__pairs = function ()
 +
-- Called when pairs is run on the args table.
 
if not metatable.donePairs then
 
if not metatable.donePairs then
mergeArgs(pairs, firstArgs, secondArgs)
+
mergeArgs(argTables)
 
metatable.donePairs = true
 
metatable.donePairs = true
metatable.doneIpairs = true
 
 
end
 
end
return pairs(metaArgs)
+
return translatenext, { t = metaArgs }
 
end
 
end
  
metatable.__ipairs = function ()
+
local function inext(t, i)
if not metatable.doneIpairs then
+
-- This uses our __index metamethod
mergeArgs(ipairs, firstArgs, secondArgs)
+
local v = t[i + 1]
metatable.doneIpairs = true
+
if v ~= nil then
 +
return i + 1, v
 
end
 
end
return ipairs(metaArgs)
 
 
end
 
end
+
 
 +
metatable.__ipairs = function (t)
 +
-- Called when ipairs is run on the args table.
 +
return inext, t, 0
 +
end
 +
 
 
return args
 
return args
 
end
 
end
  
return getArguments
+
return arguments

Latest revision as of 08:07, 23 December 2015

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 = {}

-- 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

local function matchesTitle(given, title)
	local tp = type( given )
	return (tp == 'string' or tp == 'number') and mw.title.new( given ).prefixedText == title
end

local translate_mt = { __index = function(t, k) return k end }

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

	--[[
	-- Set up argument translation.
	--]]
	options.translate = options.translate or {}
	if getmetatable(options.translate) == nil then
		setmetatable(options.translate, translate_mt)
	end
	if options.backtranslate == nil then
		options.backtranslate = {}
		for k,v in pairs(options.translate) do
			options.backtranslate[v] = k
		end
	end
	if options.backtranslate and getmetatable(options.backtranslate) == nil then
		setmetatable(options.backtranslate, {
			__index = function(t, k)
				if options.translate[k] ~= k then
					return nil
				else
					return k
				end
			end
		})
	end

	--[[
	-- Get the argument tables. If we were passed a valid frame object, get the
	-- frame arguments (fargs) and the parent frame arguments (pargs), depending
	-- on the options set and on the parent frame's availability. If we weren't
	-- passed a valid frame object, we are being called from another Lua module
	-- or from the debug console, so assume that we were passed a table of args
	-- directly, and assign it to a new variable (luaArgs).
	--]]
	local fargs, pargs, luaArgs
	if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
		if options.wrappers then
			--[[
			-- The wrappers option makes Module:Arguments look up arguments in
			-- either the frame argument table or the parent argument table, but
			-- not both. This means that users can use either the #invoke syntax
			-- or a wrapper template without the loss of performance associated
			-- with looking arguments up in both the frame and the parent frame.
			-- Module:Arguments will look up arguments in the parent frame
			-- if it finds the parent frame's title in options.wrapper;
			-- otherwise it will look up arguments in the frame object passed
			-- to getArgs.
			--]]
			local parent = frame:getParent()
			if not parent then
				fargs = frame.args
			else
				local title = parent:getTitle():gsub('/sandbox$', '')
				local found = false
				if matchesTitle(options.wrappers, title) then
					found = true
				elseif type(options.wrappers) == 'table' then
					for _,v in pairs(options.wrappers) do
						if matchesTitle(v, title) then
							found = true
							break
						end
					end
				end

				-- We test for false specifically here so that nil (the default) acts like true.
				if found or options.frameOnly == false then
					pargs = parent.args
				end
				if not found or options.parentOnly == false then
					fargs = frame.args
				end
			end
		else
			-- options.wrapper isn't set, so check the other options.
			if not options.parentOnly then
				fargs = frame.args
			end
			if not options.frameOnly then
				local parent = frame:getParent()
				pargs = parent and parent.args or nil
			end
		end
		if options.parentFirst then
			fargs, pargs = pargs, fargs
		end
	else
		luaArgs = frame
	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

	--[[
	-- 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

	--[[
	-- Set up the args, metaArgs and nilArgs tables. args will be the one
	-- accessed from functions, and metaArgs will hold the actual arguments. Nil
	-- arguments are memoized in nilArgs, and the metatable connects all of them
	-- together.
	--]]
	local args, metaArgs, nilArgs, metatable = {}, {}, {}, {}
	setmetatable(args, metatable)

	local function mergeArgs(tables)
		--[[
		-- Accepts multiple tables as input and merges their keys and values
		-- into one table. If a value is already present it is not overwritten;
		-- tables listed earlier have precedence. We are also memoizing nil
		-- values, which can be overwritten if they are 's' (soft).
		--]]
		for _, t in ipairs(tables) do
			for key, val in pairs(t) do
				if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
					local tidiedVal = tidyVal(key, val)
					if tidiedVal == nil then
						nilArgs[key] = 's'
					else
						metaArgs[key] = tidiedVal
					end
				end
			end
		end
	end

	--[[
	-- Define metatable behaviour. Arguments are memoized in the metaArgs table,
	-- and are only fetched from the argument tables once. Fetching arguments
	-- from the argument tables is the most resource-intensive step in this
	-- module, so we try and avoid it where possible. For this reason, nil
	-- arguments are also memoized, in the nilArgs table. 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 the argument tables 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)
		--[[
		-- Fetches an argument when the args table is indexed. First we check
		-- to see if the value is memoized, and if not we try and fetch it from
		-- the argument tables. When we check memoization, we need to check
		-- metaArgs before nilArgs, as both can be non-nil at the same time.
		-- If the argument is not present in metaArgs, we also check whether
		-- pairs has been run yet. If pairs has already been run, we return nil.
		-- This is because all the arguments will have already been copied into
		-- metaArgs by the mergeArgs function, meaning that any other arguments
		-- must be nil.
		--]]
		if type(key) == 'string' then
			key = options.translate[key]
		end
		local val = metaArgs[key]
		if val ~= nil then
			return val
		elseif metatable.donePairs or nilArgs[key] then
			return nil
		end
		for _, argTable in ipairs(argTables) do
			local argTableVal = tidyVal(key, argTable[key])
			if argTableVal ~= nil then
				metaArgs[key] = argTableVal
				return argTableVal
			end
		end
		nilArgs[key] = 'h'
		return nil
	end

	metatable.__newindex = function (t, key, val)
		-- This function is called when a module tries to add a new value to the
		-- args table, or tries to change an existing value.
		if type(key) == 'string' then
			key = options.translate[key]
		end
		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
			--[[
			-- If the argument is to be overwritten with nil, we need to erase
			-- the value in metaArgs, so that __index, __pairs and __ipairs do
			-- not use a previous existing value, if present; and we also need
			-- to memoize the nil in nilArgs, so that the value isn't looked
			-- up in the argument tables if it is accessed again.
			--]]
			metaArgs[key] = nil
			nilArgs[key] = 'h'
		else
			metaArgs[key] = val
		end
	end

	local function translatenext(invariant)
		local k, v = next(invariant.t, invariant.k)
		invariant.k = k
		if k == nil then
			return nil
		elseif type(k) ~= 'string' or not options.backtranslate then
			return k, v
		else
			local backtranslate = options.backtranslate[k]
			if backtranslate == nil then
				-- Skip this one. This is a tail call, so this won't cause stack overflow
				return translatenext(invariant)
			else
				return backtranslate, v
			end
		end
	end

	metatable.__pairs = function ()
		-- Called when pairs is run on the args table.
		if not metatable.donePairs then
			mergeArgs(argTables)
			metatable.donePairs = true
		end
		return translatenext, { t = metaArgs }
	end

	local function inext(t, i)
		-- This uses our __index metamethod
		local v = t[i + 1]
		if v ~= nil then
			return i + 1, v
		end
	end

	metatable.__ipairs = function (t)
		-- Called when ipairs is run on the args table.
		return inext, t, 0
	end

	return args
end

return arguments