Module:Arguments: Difference between revisions

    From Nonbinary Wiki
    (Import updated version from en.wikipedia.org)
    m (Reverted edits by Paladox2017 (talk) to last revision by Quiddity (WMF))
    Line 47: Line 47:
    return val
    return val
    end
    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)
    function arguments.getArgs(frame, options)
    Line 60: Line 53:
    frame = frame or {}
    frame = frame or {}
    options = options 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


    --[[
    --[[
    Line 114: Line 82:
    local title = parent:getTitle():gsub('/sandbox$', '')
    local title = parent:getTitle():gsub('/sandbox$', '')
    local found = false
    local found = false
    if matchesTitle(options.wrappers, title) then
    if type(options.wrappers) == 'table' then
    found = true
    elseif type(options.wrappers) == 'table' then
    for _,v in pairs(options.wrappers) do
    for _,v in pairs(options.wrappers) do
    if matchesTitle(v, title) then
    if v == title then
    found = true
    found = true
    break
    break
    end
    end
    end
    end
    elseif options.wrappers == title then
    found = true
    end
    end
     
    -- We test for false specifically here so that nil (the default) acts like true.
    -- We test for false specifically here so that nil (the default) acts like true.
    if found or options.frameOnly == false then
    if found or options.frameOnly == false then
    Line 149: Line 117:
    luaArgs = frame
    luaArgs = frame
    end
    end
     
    -- Set the order of precedence of the argument tables. If the variables are
    -- 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
    -- nil, nothing will be added to the table, which is how we avoid clashes
    -- between the frame/parent args and the Lua args.
    -- between the frame/parent args and the Lua args.
    local argTables = {fargs}
    local argTables = {fargs}
    argTables[#argTables + 1] = pargs
    argTables[#argTables + 1] = pargs
    Line 197: Line 165:
    setmetatable(args, metatable)
    setmetatable(args, metatable)


    local function mergeArgs(tables)
    local function mergeArgs(iterator, tables)
    --[[
    --[[
    -- Accepts multiple tables as input and merges their keys and values
    -- Accepts multiple tables as input and merges their keys and values
    -- into one table. If a value is already present it is not overwritten;
    -- into one table using the specified iterator. If a value is already
    -- tables listed earlier have precedence. We are also memoizing nil
    -- present it is not overwritten; tables listed earlier have precedence.
    -- values, which can be overwritten if they are 's' (soft).
    -- 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 pairs(t) do
    for key, val in iterator(t) do
    if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
    if metaArgs[key] == nil then
    local tidiedVal = tidyVal(key, val)
    local tidiedVal = tidyVal(key, val)
    if tidiedVal == nil then
    if tidiedVal == nil then
    nilArgs[key] = 's'
    nilArgs[key] = true
    else
    else
    metaArgs[key] = tidiedVal
    metaArgs[key] = tidiedVal
    Line 242: Line 211:
    -- must be nil.
    -- 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
    Line 253: Line 219:
    for _, argTable in ipairs(argTables) do
    for _, argTable in ipairs(argTables) do
    local argTableVal = tidyVal(key, argTable[key])
    local argTableVal = tidyVal(key, argTable[key])
    if argTableVal ~= nil then
    if argTableVal == nil then
    nilArgs[key] = true
    else
    metaArgs[key] = argTableVal
    metaArgs[key] = argTableVal
    return argTableVal
    return argTableVal
    end
    end
    end
    end
    nilArgs[key] = 'h'
    return nil
    return nil
    end
    end
    Line 265: Line 232:
    -- This function is called when a module tries to add a new value to the
    -- This function is called when a module tries to add a new value to the
    -- args table, or tries to change an existing value.
    -- args table, or tries to change an existing value.
    if type(key) == 'string' then
    key = options.translate[key]
    end
    if options.readOnly then
    if options.readOnly then
    error(
    error(
    Line 291: Line 255:
    --]]
    --]]
    metaArgs[key] = nil
    metaArgs[key] = nil
    nilArgs[key] = 'h'
    nilArgs[key] = true
    else
    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
    Line 318: Line 264:
    -- Called when pairs is run on the args table.
    -- Called when pairs is run on the args table.
    if not metatable.donePairs then
    if not metatable.donePairs then
    mergeArgs(argTables)
    mergeArgs(pairs, argTables)
    metatable.donePairs = true
    metatable.donePairs = true
    metatable.doneIpairs = true
    end
    end
    return translatenext, { t = metaArgs }
    return pairs(metaArgs)
    end
    end


    local function inext(t, i)
    metatable.__ipairs = function ()
    -- This uses our __index metamethod
    -- Called when ipairs is run on the args table.
    local v = t[i + 1]
    if not metatable.doneIpairs then
    if v ~= nil then
    mergeArgs(ipairs, argTables)
    return i + 1, v
    metatable.doneIpairs = true
    end
    end
    end
    return ipairs(metaArgs)
     
    metatable.__ipairs = function (t)
    -- Called when ipairs is run on the args table.
    return inext, t, 0
    end
    end



    Revision as of 16:54, 10 August 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
    
    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 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 type(options.wrappers) == 'table' then
    					for _,v in pairs(options.wrappers) do
    						if v == title then
    							found = true
    							break
    						end
    					end
    				elseif options.wrappers == title then
    					found = true
    				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(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 precedence.
    		-- 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
    				if metaArgs[key] == nil then
    					local tidiedVal = tidyVal(key, val)
    					if tidiedVal == nil then
    						nilArgs[key] = true
    					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.
    		--]]
    		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
    				nilArgs[key] = true
    			else
    				metaArgs[key] = argTableVal
    				return argTableVal
    			end
    		end
    		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 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] = true
    		else
    			metaArgs[key] = val
    		end
    	end
    
    	metatable.__pairs = function ()
    		-- Called when pairs is run on the args table.
    		if not metatable.donePairs then
    			mergeArgs(pairs, argTables)
    			metatable.donePairs = true
    			metatable.doneIpairs = true
    		end
    		return pairs(metaArgs)
    	end
    
    	metatable.__ipairs = function ()
    		-- Called when ipairs is run on the args table.
    		if not metatable.doneIpairs then
    			mergeArgs(ipairs, argTables)
    			metatable.doneIpairs = true
    		end
    		return ipairs(metaArgs)
    	end
    
    	return args
    end
    
    return arguments