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Difference between revisions of "Arguments"

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(don't use "if frame == mw.getCurrentFrame()")
(memoize nils, add type checks for frame and options, use string library functions instead of mw.text.trim and mw.ustring.find, define four different tidyVal functions to avoid checking options every time)
Line 1: Line 1:
 
-- This module provides easy processing of arguments passed to Scribunto from #invoke.
 
-- 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.
 
-- 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 arguments = {}
 +
 +
local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
 +
 +
-- 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)
 
function arguments.getArgs(frame, options)
−
options = type(options) == 'table' and options or {}
+
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
 
-- 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.
 
-- 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
 
local fargs, pargs, luaArgs
−
if type(frame) == 'table' and type(frame.args) == 'table' and type(frame.getParent) == 'function' then
+
if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
−
fargs = frame.args
+
if not options.parentOnly then
−
pargs = frame:getParent().args
+
fargs = frame.args
 +
end
 +
if not options.frameOnly then
 +
pargs = frame:getParent().args
 +
end
 +
if options.parentFirst then
 +
fargs, pargs = pargs, fargs
 +
end
 
else
 
else
−
luaArgs = type(frame) == 'table' and frame or {}
+
luaArgs = frame
 
end
 
end
  
Line 22: Line 76:
 
setmetatable(args, metatable)
 
setmetatable(args, metatable)
  
−
local function tidyVal(key, val)
+
-- Generate the tidyVal function. If it has been specified by the user, we use that; if not, we choose one of four functions
−
-- Processes a value according to the options given to getArguments. Can trim whitespace and remove blanks.
+
-- depending on the options chosen. This is so that we don't have to call the options table every time the function is called.
−
-- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage.
+
local tidyVal = options.valueFunc
−
if type(val) == 'string' then
+
if tidyVal then
−
if options.trim ~= false then
+
if type(tidyVal) ~= 'function' then
−
val = mw.text.trim(val)
+
error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2)
−
end
+
end
−
if options.removeBlanks == false or mw.ustring.find(val, '%S') then
+
elseif options.trim ~= false then
−
return val
+
if options.removeBlanks ~= false then
−
end
+
tidyVal = tidyValDefault
 
else
 
else
−
return val
+
tidyVal = tidyValTrimOnly
 
end
 
end
−
end
+
else
−
 
+
if options.removeBlanks ~= false then
−
-- Use a user-generated function to tidy the values if specified.
+
tidyVal = tidyValRemoveBlanksOnly
−
local valueFunc = options.valueFunc
 
−
if valueFunc then
 
−
local valueFuncType = type(valueFunc)
 
−
if valueFuncType == 'function' then
 
−
tidyVal = valueFunc
 
 
else
 
else
−
error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)
+
tidyVal = tidyValNoChange
 
end
 
end
 
end
 
end
Line 51: Line 100:
 
-- 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 into one table using the specified iterator.
 
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
 
-- If a value is already present it is not overwritten; tables listed earlier have precendence.
 +
-- We are also memoizing nil values, but those values can be overwritten.
 
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
−
if metaArgs[key] == nil then
+
local metaArgsVal = metaArgs[key]
−
metaArgs[key] = tidyVal(key, val)
+
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 61: Line 117:
  
 
-- Set the order of precedence of the argument tables. If the variables are nil, nothing will be added to the table,
 
-- 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.
+
-- which is how we avoid clashes between the frame/parent args and the Lua args.
−
local argTables = {}
+
local argTables = {fargs}
−
if options.frameOnly then
+
argTables[#argTables + 1] = pargs
−
table.insert(argTables, fargs)
+
argTables[#argTables + 1] = luaArgs
−
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 stored in the metaArgs table, and are only fetched from the
+
-- 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
−
-- so we do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargs
+
-- performance. Also, we keep a record in the metatable of when pairs and ipairs have been called, so we
−
-- and pargs if pairs has already been run, as all the arguments will already have been copied over.
+
-- 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
−
else
+
return nil
−
for i, argTable in ipairs(argTables) do
+
else
−
local argTableVal = tidyVal(key, argTable[key])
+
return val
−
if argTableVal ~= nil then
+
end
−
metaArgs[key] = argTableVal
+
end
−
return argTableVal
+
for _, argTable in ipairs(argTables) do
−
end
+
local argTableVal = tidyVal(key, argTable[key])
 +
if argTableVal == nil then
 +
metaArgs[key] = nilArg
 +
else
 +
metaArgs[key] = argTableVal
 +
return argTableVal
 
end
 
end
 
end
 
end
 +
return nil
 
end
 
end
  
 
metatable.__newindex = function (t, key, val)
 
metatable.__newindex = function (t, key, val)
−
if not options.readOnly and (not options.noOverwrite or args[key] == nil) then
+
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
 
metaArgs[key] = val
 
end
 
end

Revision as of 07:06, 11 December 2013

Documentation for this module may be created at Module:Arguments/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.

-- 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 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
		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.
	-- The metatable connects the two together.
	local args, metaArgs, 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 precendence.
		-- 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
				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 = {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)
		local val = metaArgs[key]
		if val ~= nil then
			if val == nilArg then
				return nil
			else
				return val
			end
		end
		for _, 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

	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
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