Modulo:Arguments

-- 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.checkTypelocal 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' thenval = val:match('^%s*(.-)%s*$')if val == '' thenreturn nilelsereturn valendelsereturn valendendlocal function tidyValTrimOnly(key, val)if type(val) == 'string' thenreturn val:match('^%s*(.-)%s*$')elsereturn valendendlocal function tidyValRemoveBlanksOnly(key, val)if type(val) == 'string' thenif val:find('%S') thenreturn valelsereturn nilendelsereturn valendendlocal function tidyValNoChange(key, val)return valendlocal function matchesTitle(given, title)local tp = type( given )return (tp == 'string' or tp == 'number') and mw.title.new( given ).prefixedText == titleendlocal 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 thensetmetatable(options.translate, translate_mt)endif options.backtranslate == nil thenoptions.backtranslate = {}for k,v in pairs(options.translate) dooptions.backtranslate[v] = kendendif options.backtranslate and getmetatable(options.backtranslate) == nil thensetmetatable(options.backtranslate, {__index = function(t, k)if options.translate[k] ~= k thenreturn nilelsereturn kendend})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, luaArgsif type(frame.args) == 'table' and type(frame.getParent) == 'function' thenif 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 thenfargs = frame.argselselocal title = parent:getTitle():gsub('/sandbox$', '')local found = falseif matchesTitle(options.wrappers, title) thenfound = trueelseif type(options.wrappers) == 'table' thenfor _,v in pairs(options.wrappers) doif matchesTitle(v, title) thenfound = truebreakendendend-- We test for false specifically here so that nil (the default) acts like true.if found or options.frameOnly == false thenpargs = parent.argsendif not found or options.parentOnly == false thenfargs = frame.argsendendelse-- options.wrapper isn't set, so check the other options.if not options.parentOnly thenfargs = frame.argsendif not options.frameOnly thenlocal parent = frame:getParent()pargs = parent and parent.args or nilendendif options.parentFirst thenfargs, pargs = pargs, fargsendelseluaArgs = frameend-- 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] = pargsargTables[#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.valueFuncif tidyVal thenif type(tidyVal) ~= 'function' thenerror("bad value assigned to option 'valueFunc'".. '(function expected, got '.. type(tidyVal).. ')',2)endelseif options.trim ~= false thenif options.removeBlanks ~= false thentidyVal = tidyValDefaultelsetidyVal = tidyValTrimOnlyendelseif options.removeBlanks ~= false thentidyVal = tidyValRemoveBlanksOnlyelsetidyVal = tidyValNoChangeendend--[[-- 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) dofor key, val in pairs(t) doif metaArgs[key] == nil and nilArgs[key] ~= 'h' thenlocal tidiedVal = tidyVal(key, val)if tidiedVal == nil thennilArgs[key] = 's'elsemetaArgs[key] = tidiedValendendendendend--[[-- 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' thenkey = options.translate[key]endlocal val = metaArgs[key]if val ~= nil thenreturn valelseif metatable.donePairs or nilArgs[key] thenreturn nilendfor _, argTable in ipairs(argTables) dolocal argTableVal = tidyVal(key, argTable[key])if argTableVal ~= nil thenmetaArgs[key] = argTableValreturn argTableValendendnilArgs[key] = 'h'return nilendmetatable.__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' thenkey = options.translate[key]endif options.readOnly thenerror('could not write to argument table key "'.. tostring(key).. '"; the table is read-only',2)elseif options.noOverwrite and args[key] ~= nil thenerror('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] = nilnilArgs[key] = 'h'elsemetaArgs[key] = valendendlocal function translatenext(invariant)local k, v = next(invariant.t, invariant.k)invariant.k = kif k == nil thenreturn nilelseif type(k) ~= 'string' or not options.backtranslate thenreturn k, velselocal backtranslate = options.backtranslate[k]if backtranslate == nil then-- Skip this one. This is a tail call, so this won't cause stack overflowreturn translatenext(invariant)elsereturn backtranslate, vendendendmetatable.__pairs = function ()-- Called when pairs is run on the args table.if not metatable.donePairs thenmergeArgs(argTables)metatable.donePairs = trueendreturn translatenext, { t = metaArgs }endlocal function inext(t, i)-- This uses our __index metamethodlocal v = t[i + 1]if v ~= nil thenreturn i + 1, vendendmetatable.__ipairs = function (t)-- Called when ipairs is run on the args table.return inext, t, 0endreturn argsendreturn arguments