Modul:Arguments

Dokumentasjon for modulen kan opprettast påModul:Arguments/dok

-- 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.

locallibraryUtil=require('libraryUtil')
localcheckType=libraryUtil.checkType

localarguments={}

-- Generate four different tidyVal functions, so that we don't have to check the
-- options every time we call it.

localfunctiontidyValDefault(key,val)
iftype(val)=='string'then
val=val:match('^%s*(.-)%s*$')
ifval==''then
returnnil
else
returnval
end
else
returnval
end
end

localfunctiontidyValTrimOnly(key,val)
iftype(val)=='string'then
returnval:match('^%s*(.-)%s*$')
else
returnval
end
end

localfunctiontidyValRemoveBlanksOnly(key,val)
iftype(val)=='string'then
ifval:find('%S')then
returnval
else
returnnil
end
else
returnval
end
end

localfunctiontidyValNoChange(key,val)
returnval
end

functionarguments.getArgs(frame,options)
checkType('getArgs',1,frame,'table',true)
checkType('getArgs',2,options,'table',true)
frame=frameor{}
options=optionsor{}

--[[
-- 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.
--]]
localfargs,pargs,luaArgs
iftype(frame.args)=='table'andtype(frame.getParent)=='function'then
ifnotoptions.parentOnlythen
fargs=frame.args
end
ifnotoptions.frameOnlythen
pargs=frame:getParent().args
end
ifoptions.parentFirstthen
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.
localargTables={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.
--]]
localtidyVal=options.valueFunc
iftidyValthen
iftype(tidyVal)~='function'then
error(
"bad value assigned to option 'valueFunc'"
..'(function expected, got '
..type(tidyVal)
..')',
2
)
end
elseifoptions.trim~=falsethen
ifoptions.removeBlanks~=falsethen
tidyVal=tidyValDefault
else
tidyVal=tidyValTrimOnly
end
else
ifoptions.removeBlanks~=falsethen
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.
--]]
localargs,metaArgs,nilArgs,metatable={},{},{},{}
setmetatable(args,metatable)

localfunctionmergeArgs(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_,tinipairs(tables)do
forkey,valiniterator(t)do
ifmetaArgs[key]==nilthen
localtidiedVal=tidyVal(key,val)
iftidiedVal==nilthen
nilArgs[key]=true
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.
--]]
localval=metaArgs[key]
ifval~=nilthen
returnval
elseifmetatable.donePairsornilArgs[key]then
returnnil
end
for_,argTableinipairs(argTables)do
localargTableVal=tidyVal(key,argTable[key])
ifargTableVal==nilthen
nilArgs[key]=true
else
metaArgs[key]=argTableVal
returnargTableVal
end
end
returnnil
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.
ifoptions.readOnlythen
error(
'could not write to argument table key "'
..tostring(key)
..' "; the table is read-only',
2
)
elseifoptions.noOverwriteandargs[key]~=nilthen
error(
'could not write to argument table key "'
..tostring(key)
..' "; overwriting existing arguments is not permitted',
2
)
elseifval==nilthen
--[[
-- 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]=true-- Memoize nils.
else
metaArgs[key]=val
end
end

metatable.__pairs=function()
-- Called when pairs is run on the args table.
ifnotmetatable.donePairsthen
mergeArgs(pairs,argTables)
metatable.donePairs=true
metatable.doneIpairs=true
end
returnpairs(metaArgs)
end

metatable.__ipairs=function()
-- Called when ipairs is run on the args table.
ifnotmetatable.doneIpairsthen
mergeArgs(ipairs,argTables)
metatable.doneIpairs=true
end
returnipairs(metaArgs)
end

returnargs
end

returnarguments