Module:Arguments: Difference between revisions
(add a more detailed comment about metatable behaviour) |
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-- This module provides easy processing of arguments passed to Scribunto from |
-- This module provides easy processing of arguments passed to Scribunto from |
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-- It is intended for use by other Lua modules, and should not be |
-- #invoke. It is intended for use by other Lua modules, and should not be |
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-- called from #invoke directly. |
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local libraryUtil = require('libraryUtil') |
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local checkType = libraryUtil.checkType |
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local arguments = {} |
local arguments = {} |
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-- Generate four different tidyVal functions, so that we don't have to check the |
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function arguments.getArgs(frame, options) |
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-- options every time we call it. |
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local function tidyValDefault(key, val) |
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-- Get the arguments from the frame object if available. If the frame object is not available, we are being called |
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if type(val) == 'string' then |
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-- from another Lua module or from the debug console, so assume arguments are passed directly in. |
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val = val:match('^%s*(.-)%s*$') |
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local fargs, pargs |
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if val == '' then |
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return nil |
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fargs = frame.args |
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else |
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pargs = frame:getParent().args |
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return val |
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end |
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else |
else |
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return val |
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fargs = type(frame) == 'table' and frame or {} |
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pargs = {} |
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end |
end |
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end |
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local function tidyValTrimOnly(key, val) |
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local args, metaArgs, metatable = {}, {}, {} |
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if type(val) == 'string' then |
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setmetatable(args, metatable) |
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return val:match('^%s*(.-)%s*$') |
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else |
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return val |
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end |
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end |
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local function tidyValRemoveBlanksOnly(key, val) |
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if type(val) == 'string' then |
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-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks. |
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if val:find('%S') then |
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-- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage. |
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return val |
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if type(val) == 'string' then |
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else |
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if options.trim ~= false then |
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return nil |
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val = mw.text.trim(val) |
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end |
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else |
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return val |
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end |
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end |
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local function tidyValNoChange(key, val) |
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return val |
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end |
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local function matchesTitle(given, title) |
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local tp = type( given ) |
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return (tp == 'string' or tp == 'number') and mw.title.new( given ).prefixedText == title |
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end |
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local translate_mt = { __index = function(t, k) return k end } |
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function arguments.getArgs(frame, options) |
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checkType('getArgs', 1, frame, 'table', true) |
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checkType('getArgs', 2, options, 'table', true) |
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frame = frame or {} |
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options = options or {} |
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--[[ |
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-- Set up argument translation. |
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--]] |
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options.translate = options.translate or {} |
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if getmetatable(options.translate) == nil then |
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setmetatable(options.translate, translate_mt) |
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end |
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if options.backtranslate == nil then |
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options.backtranslate = {} |
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for k,v in pairs(options.translate) do |
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options.backtranslate[v] = k |
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end |
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end |
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if options.backtranslate and getmetatable(options.backtranslate) == nil then |
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setmetatable(options.backtranslate, { |
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__index = function(t, k) |
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if options.translate[k] ~= k then |
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return nil |
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else |
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return k |
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end |
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end |
end |
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}) |
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if options.removeBlanks == false or mw.ustring.find(val, '%S') then |
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end |
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return val |
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--[[ |
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-- Get the argument tables. If we were passed a valid frame object, get the |
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-- frame arguments (fargs) and the parent frame arguments (pargs), depending |
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-- on the options set and on the parent frame's availability. If we weren't |
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-- passed a valid frame object, we are being called from another Lua module |
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-- or from the debug console, so assume that we were passed a table of args |
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-- directly, and assign it to a new variable (luaArgs). |
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--]] |
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local fargs, pargs, luaArgs |
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if type(frame.args) == 'table' and type(frame.getParent) == 'function' then |
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if options.wrappers then |
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--[[ |
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-- The wrappers option makes Module:Arguments look up arguments in |
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-- either the frame argument table or the parent argument table, but |
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-- not both. This means that users can use either the #invoke syntax |
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-- or a wrapper template without the loss of performance associated |
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-- with looking arguments up in both the frame and the parent frame. |
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-- Module:Arguments will look up arguments in the parent frame |
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-- if it finds the parent frame's title in options.wrapper; |
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-- otherwise it will look up arguments in the frame object passed |
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-- to getArgs. |
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--]] |
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local parent = frame:getParent() |
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if not parent then |
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fargs = frame.args |
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else |
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local title = parent:getTitle():gsub('/sandbox$', '') |
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local found = false |
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if matchesTitle(options.wrappers, title) then |
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found = true |
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elseif type(options.wrappers) == 'table' then |
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for _,v in pairs(options.wrappers) do |
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if matchesTitle(v, title) then |
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found = true |
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break |
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end |
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end |
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end |
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-- We test for false specifically here so that nil (the default) acts like true. |
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if found or options.frameOnly == false then |
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pargs = parent.args |
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end |
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if not found or options.parentOnly == false then |
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fargs = frame.args |
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end |
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end |
end |
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else |
else |
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-- options.wrapper isn't set, so check the other options. |
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return val |
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if not options.parentOnly then |
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fargs = frame.args |
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end |
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if not options.frameOnly then |
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local parent = frame:getParent() |
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pargs = parent and parent.args or nil |
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end |
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end |
end |
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if options.parentFirst then |
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fargs, pargs = pargs, fargs |
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end |
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else |
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luaArgs = frame |
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end |
end |
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-- Set the order of precedence of the argument tables. If the variables are |
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-- Use a user-generated functions to tidy the values if specified. |
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-- nil, nothing will be added to the table, which is how we avoid clashes |
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local valueFunc = options.valueFunc |
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-- between the frame/parent args and the Lua args. |
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if valueFunc then |
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local argTables = {fargs} |
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argTables[#argTables + 1] = pargs |
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if valueFuncType == 'function' then |
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argTables[#argTables + 1] = luaArgs |
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tidyVal = valueFunc |
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--[[ |
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-- Generate the tidyVal function. If it has been specified by the user, we |
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-- use that; if not, we choose one of four functions depending on the |
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-- options chosen. This is so that we don't have to call the options table |
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-- every time the function is called. |
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--]] |
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local tidyVal = options.valueFunc |
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if tidyVal then |
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if type(tidyVal) ~= 'function' then |
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error( |
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"bad value assigned to option 'valueFunc'" |
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.. '(function expected, got ' |
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.. type(tidyVal) |
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.. ')', |
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2 |
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) |
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end |
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elseif options.trim ~= false then |
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if options.removeBlanks ~= false then |
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tidyVal = tidyValDefault |
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else |
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tidyVal = tidyValTrimOnly |
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end |
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else |
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if options.removeBlanks ~= false then |
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tidyVal = tidyValRemoveBlanksOnly |
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else |
else |
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tidyVal = tidyValNoChange |
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error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2) |
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end |
end |
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end |
end |
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--[[ |
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local function mergeArgs(iterator, ...) |
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-- Set up the args, metaArgs and nilArgs tables. args will be the one |
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-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator. |
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-- accessed from functions, and metaArgs will hold the actual arguments. Nil |
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-- If a value is already present it is not overwritten; tables listed earlier have precendence. |
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-- arguments are memoized in nilArgs, and the metatable connects all of them |
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local tables = {...} |
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-- together. |
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--]] |
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local args, metaArgs, nilArgs, metatable = {}, {}, {}, {} |
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setmetatable(args, metatable) |
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local function mergeArgs(tables) |
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--[[ |
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-- Accepts multiple tables as input and merges their keys and values |
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-- into one table. If a value is already present it is not overwritten; |
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-- tables listed earlier have precedence. We are also memoizing nil |
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-- values, which can be overwritten if they are 's' (soft). |
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--]] |
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for _, t in ipairs(tables) do |
for _, t in ipairs(tables) do |
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for key, val in |
for key, val in pairs(t) do |
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if metaArgs[key] == nil then |
if metaArgs[key] == nil and nilArgs[key] ~= 'h' then |
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local tidiedVal = tidyVal(key, val) |
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if tidiedVal == nil then |
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nilArgs[key] = 's' |
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else |
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metaArgs[key] = tidiedVal |
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end |
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end |
end |
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end |
end |
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end |
end |
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end |
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-- Set the order of precedence of frame args and parent args. |
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local firstArgs, secondArgs = fargs, pargs |
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if options.parentFirst then |
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firstArgs, secondArgs = pargs, fargs |
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end |
end |
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--[[ |
--[[ |
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-- Define metatable behaviour. Arguments are |
-- Define metatable behaviour. Arguments are memoized in the metaArgs table, |
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-- and are only fetched from the argument tables once. Fetching arguments |
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-- fargs and pargs tables once. Also, we keep a record in the metatable of when pairs and ipairs have |
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-- from the argument tables is the most resource-intensive step in this |
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-- been called, so we do not run pairs and ipairs on fargs and pargs more than once. We also do not run |
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-- module, so we try and avoid it where possible. For this reason, nil |
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-- ipairs on fargs and pargs if pairs has already been run, as all the arguments will already have been |
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-- arguments are also memoized, in the nilArgs table. Also, we keep a record |
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-- copied over. |
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-- in the metatable of when pairs and ipairs have been called, so we do not |
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-- run pairs and ipairs on the argument tables more than once. We also do |
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-- not run ipairs on fargs and pargs if pairs has already been run, as all |
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-- the arguments will already have been copied over. |
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--]] |
--]] |
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metatable.__index = function (t, key) |
metatable.__index = function (t, key) |
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--[[ |
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-- Fetches an argument when the args table is indexed. First we check |
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-- to see if the value is memoized, and if not we try and fetch it from |
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-- the argument tables. When we check memoization, we need to check |
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-- metaArgs before nilArgs, as both can be non-nil at the same time. |
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-- If the argument is not present in metaArgs, we also check whether |
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-- pairs has been run yet. If pairs has already been run, we return nil. |
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-- This is because all the arguments will have already been copied into |
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-- metaArgs by the mergeArgs function, meaning that any other arguments |
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-- must be nil. |
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--]] |
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if type(key) == 'string' then |
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key = options.translate[key] |
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end |
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local val = metaArgs[key] |
local val = metaArgs[key] |
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if val ~= nil then |
if val ~= nil then |
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return val |
return val |
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elseif metatable.donePairs or nilArgs[key] then |
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else |
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return nil |
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local firstVal = tidyVal(key, firstArgs[key]) |
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end |
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if firstVal ~= nil then |
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for _, argTable in ipairs(argTables) do |
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return firstVal |
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local argTableVal = tidyVal(key, argTable[key]) |
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else |
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if argTableVal ~= nil then |
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return tidyVal(key, secondArgs[key]) |
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metaArgs[key] = argTableVal |
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return argTableVal |
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end |
end |
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end |
end |
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nilArgs[key] = 'h' |
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return nil |
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end |
end |
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metatable.__newindex = function (t, key, val) |
metatable.__newindex = function (t, key, val) |
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-- This function is called when a module tries to add a new value to the |
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if not options.readOnly and (not options.noOverwrite or metaArgs[key] == nil) then |
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-- args table, or tries to change an existing value. |
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if type(key) == 'string' then |
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key = options.translate[key] |
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end |
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if options.readOnly then |
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error( |
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'could not write to argument table key "' |
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.. tostring(key) |
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.. '"; the table is read-only', |
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2 |
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) |
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elseif options.noOverwrite and args[key] ~= nil then |
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error( |
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'could not write to argument table key "' |
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.. tostring(key) |
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.. '"; overwriting existing arguments is not permitted', |
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2 |
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) |
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elseif val == nil then |
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--[[ |
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-- If the argument is to be overwritten with nil, we need to erase |
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-- the value in metaArgs, so that __index, __pairs and __ipairs do |
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-- not use a previous existing value, if present; and we also need |
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-- to memoize the nil in nilArgs, so that the value isn't looked |
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-- up in the argument tables if it is accessed again. |
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--]] |
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metaArgs[key] = nil |
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nilArgs[key] = 'h' |
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else |
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metaArgs[key] = val |
metaArgs[key] = val |
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end |
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end |
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local function translatenext(invariant) |
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local k, v = next(invariant.t, invariant.k) |
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invariant.k = k |
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if k == nil then |
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return nil |
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elseif type(k) ~= 'string' or not options.backtranslate then |
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return k, v |
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else |
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local backtranslate = options.backtranslate[k] |
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if backtranslate == nil then |
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-- Skip this one. This is a tail call, so this won't cause stack overflow |
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return translatenext(invariant) |
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else |
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return backtranslate, v |
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end |
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end |
end |
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end |
end |
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metatable.__pairs = function () |
metatable.__pairs = function () |
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-- Called when pairs is run on the args table. |
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if not metatable.donePairs then |
if not metatable.donePairs then |
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mergeArgs( |
mergeArgs(argTables) |
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metatable.donePairs = true |
metatable.donePairs = true |
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metatable.doneIpairs = true |
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end |
end |
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return |
return translatenext, { t = metaArgs } |
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end |
end |
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local function inext(t, i) |
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-- This uses our __index metamethod |
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if not metatable.doneIpairs then |
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local v = t[i + 1] |
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mergeArgs(ipairs, firstArgs, secondArgs) |
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if v ~= nil then |
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metatable.doneIpairs = true |
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return i + 1, v |
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end |
end |
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return ipairs(metaArgs) |
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end |
end |
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metatable.__ipairs = function (t) |
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-- Called when ipairs is run on the args table. |
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return inext, t, 0 |
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end |
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return args |
return args |
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end |
end |
Latest revision as of 00:30, 28 March 2020
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