Module:Arguments: Difference between revisions
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fix undefined next() behaviour bug by checking for metatable.donePairs in the __index metamethod; also, format the module so it fits into 80 characters |
m 37 revisions imported from meta:Module:Arguments |
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(45 intermediate revisions by 32 users not shown) | |||
Line 7: | Line 7: | ||
local arguments = {} |
local arguments = {} |
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local nilArg = {} -- Used for memoizing nil arguments in metaArgs. |
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-- Generate four different tidyVal functions, so that we don't have to check the |
-- Generate four different tidyVal functions, so that we don't have to check the |
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Line 49: | Line 47: | ||
return val |
return val |
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end |
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) |
function arguments.getArgs(frame, options) |
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Line 57: | Line 62: | ||
--[[ |
--[[ |
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-- Set up argument translation. |
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-- Get the arguments from the frame object if available. If the frame object |
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--]] |
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-- is not available, we are being called from another Lua module or from the |
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options.translate = options.translate or {} |
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-- debug console, so assign the args to a new variable so we can |
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if getmetatable(options.translate) == nil then |
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-- differentiate them. |
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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 |
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}) |
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end |
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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 |
local fargs, pargs, luaArgs |
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if type(frame.args) == 'table' and type(frame.getParent) == 'function' then |
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then |
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if |
if options.wrappers then |
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--[[ |
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fargs = frame.args |
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-- The wrappers option makes Module:Arguments look up arguments in |
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end |
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-- either the frame argument table or the parent argument table, but |
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if not options.frameOnly then |
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-- not both. This means that users can use either the #invoke syntax |
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pargs = frame:getParent().args |
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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 |
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else |
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-- options.wrapper isn't set, so check the other options. |
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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 |
if options.parentFirst then |
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Line 77: | Line 150: | ||
end |
end |
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-- Set |
-- Set the order of precedence of the argument tables. If the variables are |
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-- |
-- nil, nothing will be added to the table, which is how we avoid clashes |
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-- |
-- between the frame/parent args and the Lua args. |
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local |
local argTables = {fargs} |
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argTables[#argTables + 1] = pargs |
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setmetatable(args, metatable) |
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argTables[#argTables + 1] = luaArgs |
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--[[ |
--[[ |
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Line 114: | Line 188: | ||
end |
end |
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--[[ |
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local function mergeArgs(iterator, tables) |
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-- Set up the args, metaArgs and nilArgs tables. args will be the one |
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-- accessed from functions, and metaArgs will hold the actual arguments. Nil |
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-- arguments are memoized in nilArgs, and the metatable connects all of them |
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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 |
-- Accepts multiple tables as input and merges their keys and values |
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-- into one table |
-- 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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-- We are also memoizing nil values, but those values can be |
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-- overwritten. |
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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 and nilArgs[key] ~= 'h' then |
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if metaArgsVal == nil or metaArgsVal == nilArg then |
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local tidiedVal = tidyVal(key, val) |
local tidiedVal = tidyVal(key, val) |
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if tidiedVal == nil then |
if tidiedVal == nil then |
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nilArgs[key] = 's' |
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else |
else |
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metaArgs[key] = tidiedVal |
metaArgs[key] = tidiedVal |
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Line 136: | Line 217: | ||
end |
end |
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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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-- nil, nothing will be added to the table, which is how we avoid clashes |
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-- between the frame/parent args and the Lua args. |
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local argTables = {fargs} |
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argTables[#argTables + 1] = pargs |
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argTables[#argTables + 1] = luaArgs |
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--[[ |
--[[ |
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-- Define metatable behaviour. Arguments are memoized in the metaArgs table, |
-- Define metatable behaviour. Arguments are memoized in the metaArgs table, |
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-- and are only fetched from the argument tables once. |
-- and are only fetched from the argument tables once. Fetching arguments |
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-- from the argument tables is the most resource-intensive step in this |
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-- also memoized using the nilArg variable in order to increase performance. |
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-- |
-- module, so we try and avoid it where possible. For this reason, nil |
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-- arguments are also memoized, in the nilArgs table. Also, we keep a record |
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-- been called, so we do not run pairs and ipairs on fargs and pargs more |
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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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-- over. |
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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 |
if val ~= nil then |
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return val |
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elseif metatable.donePairs or nilArgs[key] then |
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-- We have either memoized the argument already, or pairs has been |
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return nil |
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-- called, meaning that mergeArgs has already copied all of the |
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-- available arguments into the metaArgs table. We need to check for |
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-- pairs as we can't memoize nils to the metaArgs table while pairs |
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-- is iterating. Adding new instances of nilArg to the metaArgs |
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-- table while pairs is iterating over it produces undefined |
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-- behaviour in the next() function. |
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--]] |
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if val == nilArg then |
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return nil |
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else |
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return val |
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end |
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end |
end |
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for _, argTable in ipairs(argTables) do |
for _, argTable in ipairs(argTables) do |
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local argTableVal = tidyVal(key, argTable[key]) |
local argTableVal = tidyVal(key, argTable[key]) |
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if argTableVal |
if argTableVal ~= nil then |
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metaArgs[key] = nilArg |
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else |
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metaArgs[key] = argTableVal |
metaArgs[key] = argTableVal |
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return argTableVal |
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 |
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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-- 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 |
if options.readOnly then |
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error( |
error( |
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Line 201: | Line 283: | ||
) |
) |
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elseif val == nil then |
elseif val == nil then |
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--[[ |
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metaArgs[key] = nilArg -- Memoize nils. |
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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 |
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 |
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return function (t, k) |
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local nk, val = next(metaArgs, k) |
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if val == nilArg then |
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val = nil |
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end |
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return nk, val |
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end |
end |
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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, argTables) |
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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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end |
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return function (t, i) |
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local val = metaArgs[i + 1] |
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metatable.__ipairs = function (t) |
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if val == nil then |
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-- Called when ipairs is run on the args table. |
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return nil |
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return inext, t, 0 |
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elseif val == nilArg then |
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val = nil |
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end |
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return i + 1, val |
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end, nil, 0 |
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end |
end |
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