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Module:Arguments

1,401 bytes added, 05:06, 11 December 2013
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
-- 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)
options = typecheckType('getArgs', 1, frame, 'table', true) checkType('getArgs', 2, options, 'table', true) frame =frame or {} 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 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 = type(frame) == 'table' and frame or {}
end
setmetatable(args, metatable)
local -- Generate the tidyVal function tidyVal(key. If it has been specified by the user, we use that; if not, val)we choose one of four functions -- Processes a value according depending on the options chosen. This is so that we don't have to call the options given to getArgumentstable every time the function is called. Can trim whitespace and remove blanks local tidyVal = options.valueFunc -- Keys are not used here, but they can be used by user-generated functions, so defining it here to avoid breakage. if tidyVal then if type(valtidyVal) =~= 'stringfunction' then if error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2) end elseif options.trim ~= false then val = mw.text.trim(val) end if options.removeBlanks =~= false or mw.ustring.find(val, '%S') then return val endtidyVal = tidyValDefault
else
return valtidyVal = tidyValTrimOnly
end
endelse  -- Use a user-generated function to tidy the values if specified. local valueFunc = options.valueFunc if valueFunc then local valueFuncType = type(valueFunc) if valueFuncType =removeBlanks ~= 'function' false then tidyVal = valueFunctidyValRemoveBlanksOnly
else
error('type error in option "valueFunc": expected function, got ' .. valueFuncType, 2)tidyVal = tidyValNoChange
end
end
-- 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
if local metaArgsVal = metaArgs[key] if metaArgsVal == nil or metaArgsVal == nilArg then metaArgs[key] local tidiedVal = tidyVal(key, val) if tidiedVal == nil then metaArgs[key] = nilArg else metaArgs[key] = tidiedVal 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} if options.frameOnly then table.insert(argTables, fargs) elseif options.parentOnly then table.insert([#argTables, + 1] = 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, + 1] = luaArgs)
--[[
-- Define metatable behaviour. Arguments are stored 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 -- so we do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargsand -- 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 elseend 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
end
return nil
end
metatable.__newindex = function (t, key, val)
if not options.readOnly and then error('could not write to argument table key "' .. tostring(key) .. '"; the table is read-only', 2) elseif options.noOverwrite or 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
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