Difference between revisions of "Module:Arguments/sandbox"
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blackwiki>Mr. Stradivarius (make the code fit within 80 characters) |
blackwiki>Jackmcbarn (memoize nils in a different way (unfortunately an edit conflict kept me from saving the line length changes)) |
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Line 1: | Line 1: | ||
− | -- This module provides easy processing of arguments passed to Scribunto from | + | -- 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 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 options every time we call it. | |
− | |||
− | -- Generate four different tidyVal functions, so that we don't have to check the | ||
− | |||
local function tidyValDefault(key, val) | local function tidyValDefault(key, val) | ||
Line 56: | Line 52: | ||
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 | |
− | -- Get the arguments from the frame object if available. If the frame object | + | -- from another Lua module or from the debug console, so assign the args to a new variable so we can differentiate them. |
− | |||
− | |||
− | |||
− | |||
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 | ||
Line 77: | Line 69: | ||
end | end | ||
− | -- Set up the args and metaArgs tables. args will be the one accessed from | + | -- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments. |
− | + | -- nilArgs contains keys of elements established to contain nil values. The metatable connects these together. | |
− | -- connects | + | local args, metaArgs, nilArgs, metatable = {}, {}, {}, {} |
− | local args, metaArgs, metatable = {}, {}, {} | ||
setmetatable(args, metatable) | setmetatable(args, metatable) | ||
− | + | -- 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. |
− | |||
− | -- options chosen. This is so that we don't have to call the options table | ||
− | |||
− | |||
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) |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
end | end | ||
elseif options.trim ~= false then | elseif options.trim ~= false then | ||
Line 115: | Line 96: | ||
local function mergeArgs(iterator, tables) | local function mergeArgs(iterator, tables) | ||
− | + | -- Accepts multiple tables as input and merges their keys and values into one table using the specified iterator. | |
− | -- Accepts multiple tables as input and merges their keys and values | + | -- If a value is already present it is not overwritten; tables listed earlier have precedence. |
− | + | -- We are also memoizing nil values, but those values can be overwritten. | |
− | |||
− | -- We are also memoizing nil values, but those values can be | ||
− | |||
− | |||
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 not nilArgs[key] then |
− | + | local metaArgsVal = metaArgs[key] | |
− | + | if metaArgsVal == nil then | |
− | + | local tidiedVal = tidyVal(key, val) | |
− | + | if tidiedVal == nil then | |
− | + | nilArgs[key] = true | |
− | + | else | |
+ | metaArgs[key] = tidiedVal | ||
+ | end | ||
end | end | ||
end | end | ||
Line 137: | Line 116: | ||
end | end | ||
− | -- Set the order of precedence of the argument tables. If the variables are | + | -- 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} | local argTables = {fargs} | ||
argTables[#argTables + 1] = pargs | argTables[#argTables + 1] = pargs | ||
Line 145: | Line 123: | ||
--[[ | --[[ | ||
− | -- 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 |
− | + | -- 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 | |
− | -- Also, we keep a record in the metatable of when pairs and ipairs have | + | -- 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) | ||
+ | if nilArgs[key] then | ||
+ | return nil | ||
+ | end | ||
local val = metaArgs[key] | local val = metaArgs[key] | ||
if val ~= nil then | if val ~= nil then | ||
− | + | return val | |
− | |||
− | |||
− | |||
− | |||
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 | ||
− | + | nilArgs[key] = true | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
else | else | ||
metaArgs[key] = argTableVal | metaArgs[key] = argTableVal | ||
Line 187: | Line 152: | ||
metatable.__newindex = function (t, key, val) | metatable.__newindex = function (t, key, val) | ||
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) |
− | + | elseif options.noOverwrite and (args[key] ~= nil or nilArgs[key]) then | |
− | + | error('could not write to argument table key "' .. tostring(key) .. '"; overwriting existing arguments is not permitted', 2) | |
− | |||
− | |||
− | |||
− | elseif options.noOverwrite and args[key] ~= nil then | ||
− | error( | ||
− | |||
− | |||
− | |||
− | |||
− | |||
elseif val == nil then | elseif val == nil then | ||
− | metaArgs[key] = | + | -- Memoize nils. |
+ | nilArgs[key] = true | ||
+ | metaArgs[key] = nil | ||
else | else | ||
+ | nilArgs[key] = nil | ||
metaArgs[key] = val | metaArgs[key] = val | ||
end | end | ||
Line 214: | Line 172: | ||
end | end | ||
return function (t, k) | return function (t, k) | ||
− | + | return next(metaArgs, k) | |
− | |||
− | |||
− | |||
− | |||
end | end | ||
end | end | ||
Line 228: | Line 182: | ||
end | end | ||
return function (t, i) | return function (t, i) | ||
+ | if nilArgs[i + 1] then | ||
+ | return nil | ||
+ | end | ||
local val = metaArgs[i + 1] | local val = metaArgs[i + 1] | ||
if val == nil then | if val == nil then | ||
return nil | return nil | ||
− | |||
− | |||
end | end | ||
return i + 1, val | return i + 1, val |
Revision as of 23:12, 13 April 2014
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 = {}
-- 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
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 assign the args to a new variable so we can differentiate them.
local fargs, pargs, luaArgs
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
if not options.parentOnly then
fargs = frame.args
end
if not options.frameOnly then
pargs = frame:getParent().args
end
if options.parentFirst then
fargs, pargs = pargs, fargs
end
else
luaArgs = frame
end
-- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments.
-- nilArgs contains keys of elements established to contain nil values. The metatable connects these together.
local args, metaArgs, nilArgs, metatable = {}, {}, {}, {}
setmetatable(args, metatable)
-- 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
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 precedence.
-- We are also memoizing nil values, but those values can be overwritten.
for _, t in ipairs(tables) do
for key, val in iterator(t) do
if not nilArgs[key] then
local metaArgsVal = metaArgs[key]
if metaArgsVal == nil then
local tidiedVal = tidyVal(key, val)
if tidiedVal == nil then
nilArgs[key] = true
else
metaArgs[key] = tidiedVal
end
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 = {fargs}
argTables[#argTables + 1] = pargs
argTables[#argTables + 1] = 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)
if nilArgs[key] then
return nil
end
local val = metaArgs[key]
if val ~= nil then
return val
end
for _, argTable in ipairs(argTables) do
local argTableVal = tidyVal(key, argTable[key])
if argTableVal == nil then
nilArgs[key] = true
else
metaArgs[key] = argTableVal
return argTableVal
end
end
return nil
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 or nilArgs[key]) then
error('could not write to argument table key "' .. tostring(key) .. '"; overwriting existing arguments is not permitted', 2)
elseif val == nil then
-- Memoize nils.
nilArgs[key] = true
metaArgs[key] = nil
else
nilArgs[key] = nil
metaArgs[key] = val
end
end
metatable.__pairs = function ()
if not metatable.donePairs then
mergeArgs(pairs, argTables)
metatable.donePairs = true
metatable.doneIpairs = true
end
return function (t, k)
return next(metaArgs, k)
end
end
metatable.__ipairs = function ()
if not metatable.doneIpairs then
mergeArgs(ipairs, argTables)
metatable.doneIpairs = true
end
return function (t, i)
if nilArgs[i + 1] then
return nil
end
local val = metaArgs[i + 1]
if val == nil then
return nil
end
return i + 1, val
end, nil, 0
end
return args
end
return arguments