Editing Module:Arguments

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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 #invoke.
−
-- #invoke. It is intended for use by other Lua modules, and should not be
+
-- It is intended for use by other Lua modules, and should not be called from #invoke directly.
−
-- called from #invoke directly.
 
  
 
local libraryUtil = require('libraryUtil')
 
local libraryUtil = require('libraryUtil')
Line 8: Line 7:
 
local arguments = {}
 
local arguments = {}
  
−
-- Generate four different tidyVal functions, so that we don't have to check the
+
local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
−
-- options every time we call it.
+
 
 +
-- 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)
 
local function tidyValDefault(key, val)
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 61: Line 54:
 
options = options or {}
 
options = options or {}
  
−
--[[
+
-- Get the arguments from the frame object if available. If the frame object is not available, we are being called
−
-- Set up argument translation.
+
-- from another Lua module or from the debug console, so assign the args to a new variable so we can differentiate them.
−
--]]
 
−
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
 
local fargs, pargs, luaArgs
 
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
 
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
−
if options.wrappers then
+
if not options.parentOnly then
−
--[[
+
fargs = frame.args
−
-- The wrappers option makes Module:Arguments look up arguments in
+
end
−
-- either the frame argument table or the parent argument table, but
+
if not options.frameOnly then
−
-- not both. This means that users can use either the #invoke syntax
+
pargs = frame:getParent().args
−
-- 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
 
end
 
if options.parentFirst then
 
if options.parentFirst then
Line 150: Line 71:
 
end
 
end
  
−
-- Set the order of precedence of the argument tables. If the variables are
+
-- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments.
−
-- nil, nothing will be added to the table, which is how we avoid clashes
+
-- The metatable connects the two together.
−
-- between the frame/parent args and the Lua args.
+
local args, metaArgs, metatable = {}, {}, {}
−
local argTables = {fargs}
+
setmetatable(args, metatable)
−
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
−
-- Generate the tidyVal function. If it has been specified by the user, we
+
-- depending on the options chosen. This is so that we don't have to call the options table every time the function is called.
−
-- 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
 
local tidyVal = options.valueFunc
 
if tidyVal then
 
if tidyVal then
 
if type(tidyVal) ~= 'function' then
 
if type(tidyVal) ~= 'function' then
−
error(
+
error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2)
−
"bad value assigned to option 'valueFunc'"
 
−
.. '(function expected, got '
 
−
.. type(tidyVal)
 
−
.. ')',
 
−
2
 
−
)
 
 
end
 
end
 
elseif options.trim ~= false then
 
elseif options.trim ~= false then
Line 188: Line 97:
 
end
 
end
  
−
--[[
+
local function mergeArgs(iterator, tables)
−
-- Set up the args, metaArgs and nilArgs tables. args will be the one
+
-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
−
-- accessed from functions, and metaArgs will hold the actual arguments. Nil
+
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
−
-- arguments are memoized in nilArgs, and the metatable connects all of them
+
-- We are also memoizing nil values, but those values can be overwritten.
−
-- together.
 
−
--]]
 
−
local args, metaArgs, nilArgs, metatable = {}, {}, {}, {}
 
−
setmetatable(args, metatable)
 
−
 
 
−
local function mergeArgs(tables)
 
−
--[[
 
−
-- Accepts multiple tables as input and merges their keys and values
 
−
-- into one table. If a value is already present it is not overwritten;
 
−
-- tables listed earlier have precedence. We are also memoizing nil
 
−
-- values, which can be overwritten if they are 's' (soft).
 
−
--]]
 
 
for _, t in ipairs(tables) do
 
for _, t in ipairs(tables) do
−
for key, val in pairs(t) do
+
for key, val in iterator(t) do
−
if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
+
local metaArgsVal = metaArgs[key]
 +
if metaArgsVal == nil or metaArgsVal == nilArg then
 
local tidiedVal = tidyVal(key, val)
 
local tidiedVal = tidyVal(key, val)
 
if tidiedVal == nil then
 
if tidiedVal == nil then
−
nilArgs[key] = 's'
+
metaArgs[key] = nilArg
 
else
 
else
 
metaArgs[key] = tidiedVal
 
metaArgs[key] = tidiedVal
Line 217: Line 115:
 
end
 
end
 
end
 
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
  
 
--[[
 
--[[
−
-- Define metatable behaviour. Arguments are memoized in the metaArgs table,
+
-- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the
−
-- and are only fetched from the argument tables once. Fetching arguments
+
-- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase
−
-- from the argument tables is the most resource-intensive step in this
+
-- performance. Also, we keep a record in the metatable of when pairs and ipairs have been called, so we
−
-- module, so we try and avoid it where possible. For this reason, nil
+
-- do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargs and
−
-- arguments are also memoized, in the nilArgs table. Also, we keep a record
+
-- pargs if pairs has already been run, as all the arguments will already have been copied over.
−
-- in the metatable of when pairs and ipairs have been called, so we do not
 
−
-- run pairs and ipairs on the argument tables more than once. We also do
 
−
-- not run ipairs on fargs and pargs if pairs has already been run, as all
 
−
-- the arguments will already have been copied over.
 
 
--]]
 
--]]
  
 
metatable.__index = function (t, key)
 
metatable.__index = function (t, key)
−
--[[
 
−
-- Fetches an argument when the args table is indexed. First we check
 
−
-- to see if the value is memoized, and if not we try and fetch it from
 
−
-- the argument tables. When we check memoization, we need to check
 
−
-- metaArgs before nilArgs, as both can be non-nil at the same time.
 
−
-- If the argument is not present in metaArgs, we also check whether
 
−
-- pairs has been run yet. If pairs has already been run, we return nil.
 
−
-- This is because all the arguments will have already been copied into
 
−
-- metaArgs by the mergeArgs function, meaning that any other arguments
 
−
-- must be nil.
 
−
--]]
 
−
if type(key) == 'string' then
 
−
key = options.translate[key]
 
−
end
 
 
local val = metaArgs[key]
 
local val = metaArgs[key]
 
if val ~= nil then
 
if val ~= nil then
−
return val
+
if val == nilArg then
−
elseif metatable.donePairs or nilArgs[key] then
+
return nil
−
return nil
+
else
 +
return val
 +
end
 
end
 
end
 
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
 +
metaArgs[key] = nilArg
 +
else
 
metaArgs[key] = argTableVal
 
metaArgs[key] = argTableVal
 
return argTableVal
 
return argTableVal
 
end
 
end
 
end
 
end
−
nilArgs[key] = 'h'
 
 
return nil
 
return nil
 
end
 
end
  
 
metatable.__newindex = function (t, key, val)
 
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
 
if options.readOnly then
−
error(
+
error('could not write to argument table key "' .. tostring(key) .. '"; the table is read-only', 2)
−
'could not write to argument table key "'
 
−
.. tostring(key)
 
−
.. '"; the table is read-only',
 
−
2
 
−
)
 
 
elseif options.noOverwrite and args[key] ~= nil then
 
elseif options.noOverwrite and args[key] ~= nil then
−
error(
+
error('could not write to argument table key "' .. tostring(key) .. '"; overwriting existing arguments is not permitted', 2)
−
'could not write to argument table key "'
 
−
.. tostring(key)
 
−
.. '"; overwriting existing arguments is not permitted',
 
−
2
 
−
)
 
 
elseif val == nil then
 
elseif val == nil then
−
--[[
+
metaArgs[key] = nilArg -- Memoize nils.
−
-- 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
 
else
 
metaArgs[key] = val
 
metaArgs[key] = val
−
end
 
−
end
 
−
 
−
local function translatenext(invariant)
 
−
local k, v = next(invariant.t, invariant.k)
 
−
invariant.k = k
 
−
if k == nil then
 
−
return nil
 
−
elseif type(k) ~= 'string' or not options.backtranslate then
 
−
return k, v
 
−
else
 
−
local backtranslate = options.backtranslate[k]
 
−
if backtranslate == nil then
 
−
-- Skip this one. This is a tail call, so this won't cause stack overflow
 
−
return translatenext(invariant)
 
−
else
 
−
return backtranslate, v
 
−
end
 
 
end
 
end
 
end
 
end
  
 
metatable.__pairs = function ()
 
metatable.__pairs = function ()
−
-- Called when pairs is run on the args table.
 
 
if not metatable.donePairs then
 
if not metatable.donePairs then
−
mergeArgs(argTables)
+
mergeArgs(pairs, argTables)
 
metatable.donePairs = true
 
metatable.donePairs = true
 +
metatable.doneIpairs = true
 +
end
 +
return function ( t, k )
 +
local nk, val = next( metaArgs, k )
 +
if val == nilArg then
 +
val = nil
 +
end
 +
return nk, val
 
end
 
end
−
return translatenext, { t = metaArgs }
 
 
end
 
end
  
−
local function inext(t, i)
+
metatable.__ipairs = function ()
−
-- This uses our __index metamethod
+
if not metatable.doneIpairs then
−
local v = t[i + 1]
+
mergeArgs(ipairs, argTables)
−
if v ~= nil then
+
metatable.doneIpairs = true
−
return i + 1, v
 
 
end
 
end
−
end
+
return function ( t, i )
−
 
+
local val = metaArgs[i + 1]
−
metatable.__ipairs = function (t)
+
if val == nil then
−
-- Called when ipairs is run on the args table.
+
return nil
−
return inext, t, 0
+
elseif val == nilArg then
 +
val = nil
 +
end
 +
return i + 1, val
 +
end, nil, 0
 
end
 
end
  

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