Difference between revisions of "Module:Arguments/sandbox"
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blackwiki>Mr. Stradivarius (return an explicit nil from tidyVal) |
blackwiki>Mr. Stradivarius (memoize nil args) |
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Line 6: | Line 6: | ||
local arguments = {} | local arguments = {} | ||
+ | |||
+ | local nilArg = {} -- Used for memoizing nil arguments in metaArgs. | ||
function arguments.getArgs(frame, options) | function arguments.getArgs(frame, options) | ||
Line 60: | Line 62: | ||
for _, t in ipairs(tables) do | for _, t in ipairs(tables) do | ||
for key, val in iterator(t) do | for key, val in iterator(t) do | ||
− | + | local metaArgsVal = metaArgs[key] | |
− | + | if metaArgsVal == nil or metaArgsVal == nilArg then | |
+ | local tidiedVal = tidyVal(key, val) | ||
+ | if tidiedVal == nil then | ||
+ | metaArgs[key] = nilArg | ||
+ | else | ||
+ | metaArgs[key] = tidiedVal | ||
+ | end | ||
end | end | ||
end | end | ||
Line 84: | Line 92: | ||
--[[ | --[[ | ||
− | -- Define metatable behaviour. Arguments are | + | -- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the |
− | -- argument tables once. Also, we keep a record in the metatable of when pairs and ipairs have been called, | + | -- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase |
− | -- | + | -- performance. 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 fargs and pargs 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) | ||
local val = metaArgs[key] | local val = metaArgs[key] | ||
if val ~= nil then | if val ~= nil then | ||
− | return val | + | if val == nilArg then |
+ | return nil | ||
+ | else | ||
+ | return val | ||
+ | end | ||
else | else | ||
for i, argTable in ipairs(argTables) do | for i, argTable in ipairs(argTables) do | ||
local argTableVal = tidyVal(key, argTable[key]) | local argTableVal = tidyVal(key, argTable[key]) | ||
− | if argTableVal | + | if argTableVal == nil then |
+ | metaArgs[key] = nilArg | ||
+ | else | ||
metaArgs[key] = argTableVal | metaArgs[key] = argTableVal | ||
return argTableVal | return argTableVal | ||
end | end | ||
end | end | ||
+ | return nil | ||
end | end | ||
end | end | ||
Line 109: | Line 125: | ||
elseif options.noOverwrite and args[key] ~= nil then | 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) | error('could not write to argument table key "' .. tostring(key) .. '"; overwriting existing arguments is not permitted', 2) | ||
+ | elseif val == nil then | ||
+ | metaArgs[key] = nilArg -- Memoize nils. | ||
else | else | ||
metaArgs[key] = val | metaArgs[key] = val |
Revision as of 06:44, 11 December 2013
Documentation for this module may be created at Module:Arguments/sandbox/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 = {}
local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
function arguments.getArgs(frame, options)
checkType('getArgs', 1, frame, 'table', true)
checkType('getArgs', 2, options, 'table', true)
frame = frame or {}
options = options or {}
-- Get the arguments from the frame object if available. If the frame object is not available, we are being called
-- from another Lua module or from the debug console, so put the args in a special table so we can differentiate them.
local fargs, pargs, luaArgs
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
fargs = frame.args
pargs = frame:getParent().args
else
luaArgs = type(frame) == 'table' and frame or {}
end
-- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments.
-- The metatable connects the two together.
local args, metaArgs, metatable = {}, {}, {}
setmetatable(args, metatable)
local function tidyVal(key, val)
-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks.
-- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage.
if type(val) == 'string' then
if options.trim ~= false then
val = val:match('^%s*(.-)%s*$')
end
if options.removeBlanks == false or val:find('%S') then
return val
end
else
return val
end
return nil
end
-- Use a user-generated function to tidy the values if specified.
local valueFunc = options.valueFunc
if valueFunc then
local valueFuncType = type(valueFunc)
if valueFuncType == 'function' then
tidyVal = valueFunc
else
error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)
end
end
local function mergeArgs(iterator, tables)
-- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator.
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
for _, t in ipairs(tables) do
for key, val in iterator(t) do
local metaArgsVal = metaArgs[key]
if metaArgsVal == nil or metaArgsVal == nilArg then
local tidiedVal = tidyVal(key, val)
if tidiedVal == nil then
metaArgs[key] = nilArg
else
metaArgs[key] = tidiedVal
end
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 = {}
if options.frameOnly then
table.insert(argTables, fargs)
elseif options.parentOnly then
table.insert(argTables, pargs)
elseif options.parentFirst then
table.insert(argTables, pargs)
table.insert(argTables, fargs)
else
table.insert(argTables, fargs)
table.insert(argTables, pargs)
end
table.insert(argTables, luaArgs)
--[[
-- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the
-- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase
-- performance. 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 fargs and pargs 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)
local val = metaArgs[key]
if val ~= nil then
if val == nilArg then
return nil
else
return val
end
else
for i, argTable in ipairs(argTables) do
local argTableVal = tidyVal(key, argTable[key])
if argTableVal == nil then
metaArgs[key] = nilArg
else
metaArgs[key] = argTableVal
return argTableVal
end
end
return nil
end
end
metatable.__newindex = function (t, key, val)
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
metaArgs[key] = nilArg -- Memoize nils.
else
metaArgs[key] = val
end
end
metatable.__pairs = function ()
if not metatable.donePairs then
mergeArgs(pairs, argTables)
metatable.donePairs = true
metatable.doneIpairs = true
end
return pairs(metaArgs)
end
metatable.__ipairs = function ()
if not metatable.doneIpairs then
mergeArgs(ipairs, argTables)
metatable.doneIpairs = true
end
return ipairs(metaArgs)
end
return args
end
return arguments