Arguments
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Revision as of 15:50, 10 December 2013 by Mr. Stradivarius (talk) (don't use "if frame == mw.getCurrentFrame()")
Revision as of 15:50, 10 December 2013 by Mr. Stradivarius (talk) (don't use "if frame == mw.getCurrentFrame()")
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 arguments = {}
function arguments.getArgs(frame, options)
options = type(options) == 'table' and 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) == 'table' and 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 = mw.text.trim(val)
end
if options.removeBlanks == false or mw.ustring.find(val, '%S') then
return val
end
else
return val
end
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
if metaArgs[key] == nil then
metaArgs[key] = tidyVal(key, val)
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 stored 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,
-- 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
return val
else
for i, argTable in ipairs(argTables) do
local argTableVal = tidyVal(key, argTable[key])
if argTableVal ~= nil then
metaArgs[key] = argTableVal
return argTableVal
end
end
end
end
metatable.__newindex = function (t, key, val)
if not options.readOnly and (not options.noOverwrite or args[key] == nil) then
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