Difference between revisions of "Module:Arguments"

(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 (20 revisions)
 
(5 intermediate revisions by 2 users not shown)
Line 7: Line 7:
  
 
local arguments = {}
 
local arguments = {}
 
local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
 
  
 
-- 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
Line 48: Line 46:
 
local function tidyValNoChange(key, val)
 
local function tidyValNoChange(key, val)
 
return 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
 
end
  
Line 57: Line 60:
  
 
--[[
 
--[[
-- Get the arguments from the frame object if available. If the frame object
+
-- Get the argument tables. If we were passed a valid frame object, get the
-- is not available, we are being called from another Lua module or from the
+
-- frame arguments (fargs) and the parent frame arguments (pargs), depending
-- debug console, so assign the args to a new variable so we can
+
-- on the options set and on the parent frame's availability. If we weren't
-- differentiate them.
+
-- 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 not options.parentOnly then
+
if options.wrappers then
fargs = frame.args
+
--[[
end
+
-- The wrappers option makes Module:Arguments look up arguments in
if not options.frameOnly then
+
-- either the frame argument table or the parent argument table, but
pargs = frame:getParent().args
+
-- 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
 
end
 
if options.parentFirst then
 
if options.parentFirst then
Line 76: Line 122:
 
luaArgs = frame
 
luaArgs = frame
 
end
 
end
 
+
-- Set up the args and metaArgs tables. args will be the one accessed from
+
-- Set the order of precedence of the argument tables. If the variables are
-- functions, and metaArgs will hold the actual arguments. The metatable
+
-- nil, nothing will be added to the table, which is how we avoid clashes
-- 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
  
 
--[[
 
--[[
Line 114: Line 161:
 
end
 
end
  
local function mergeArgs(iterator, tables)
+
--[[
 +
-- 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
 
-- Accepts multiple tables as input and merges their keys and values
-- into one table using the specified iterator. If a value is already
+
-- into one table. If a value is already present it is not overwritten;
-- present it is not overwritten; tables listed earlier have precedence.
+
-- tables listed earlier have precedence. We are also memoizing nil
-- We are also memoizing nil values, but those values can be
+
-- values, which can be overwritten if they are 's' (soft).
-- overwritten.
 
 
--]]
 
--]]
 
for _, t in ipairs(tables) do
 
for _, t in ipairs(tables) do
for key, val in iterator(t) do
+
for key, val in pairs(t) do
local metaArgsVal = metaArgs[key]
+
if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
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
metaArgs[key] = nilArg
+
nilArgs[key] = 's'
 
else
 
else
 
metaArgs[key] = tidiedVal
 
metaArgs[key] = tidiedVal
Line 136: Line 190:
 
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 argument tables once. Nil arguments are
+
-- and are only fetched from the argument tables once. Fetching arguments
-- also memoized using the nilArg variable in order to increase performance.
+
-- from the argument tables is the most resource-intensive step in this
-- Also, we keep a record in the metatable of when pairs and ipairs have
+
-- module, so we try and avoid it where possible. For this reason, nil
-- been called, so we do not run pairs and ipairs on fargs and pargs more
+
-- arguments are also memoized, in the nilArgs table. Also, we keep a record
-- than once. We also do not run ipairs on fargs and pargs if pairs has
+
-- in the metatable of when pairs and ipairs have been called, so we do not
-- already been run, as all the arguments will already have been copied
+
-- run pairs and ipairs on the argument tables more than once. We also do
-- over.
+
-- 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.
 +
--]]
 
local val = metaArgs[key]
 
local val = metaArgs[key]
if metatable.donePairs or val ~= nil then
+
if val ~= nil then
--[[
+
return val
-- We have either memoized the argument already, or pairs has been
+
elseif metatable.donePairs or nilArgs[key] then
-- called, meaning that mergeArgs has already copied all of the
+
return nil
-- available arguments into the metaArgs table. We need to check for
 
-- pairs as we can't memoize nils to the metaArgs table while pairs
 
-- is iterating. Adding new instances of nilArg to the metaArgs
 
-- table while pairs is iterating over it produces undefined
 
-- behaviour in the next() function.
 
--]]
 
if val == nilArg then
 
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 options.readOnly then
 
if options.readOnly then
 
error(
 
error(
Line 201: Line 250:
 
)
 
)
 
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
Line 208: Line 265:
  
 
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(pairs, argTables)
+
mergeArgs(argTables)
 
metatable.donePairs = true
 
metatable.donePairs = true
metatable.doneIpairs = true
 
 
end
 
end
return function (t, k)
+
return pairs(metaArgs)
local nk, val = next(metaArgs, k)
+
end
if val == nilArg then
+
val = nil
+
local function inext(t, i)
end
+
-- This uses our __index metamethod
return nk, val
+
local v = t[i + 1]
 +
if v ~= nil then
 +
return i + 1, v
 
end
 
end
 
end
 
end
  
metatable.__ipairs = function ()
+
metatable.__ipairs = function (t)
if not metatable.doneIpairs then
+
-- Called when ipairs is run on the args table.
mergeArgs(ipairs, argTables)
+
return inext, t, 0
metatable.doneIpairs = true
 
end
 
return function (t, i)
 
local val = metaArgs[i + 1]
 
if val == nil then
 
return nil
 
elseif val == nilArg then
 
val = nil
 
end
 
return i + 1, val
 
end, nil, 0
 
 
end
 
end
  

Latest revision as of 13:03, 9 February 2015

-- 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

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 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. --]] 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 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

metatable.__pairs = function () -- Called when pairs is run on the args table. if not metatable.donePairs then mergeArgs(argTables) metatable.donePairs = true end return pairs(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