Module:Arguments: Difference between revisions

    (Created page with "-- 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 di...")
    m>Mr. Stradivarius
    (fix undefined next() behaviour bug by checking for metatable.donePairs in the __index metamethod; also, format the module so it fits into 80 characters)
    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
    -- It is intended for use by other Lua modules, and should not be called from #invoke directly.
    -- #invoke. It is intended for use by other Lua modules, and should not be
    -- called from #invoke directly.
     
    local libraryUtil = require('libraryUtil')
    local libraryUtil = require('libraryUtil')
    local checkType = libraryUtil.checkType
    local checkType = libraryUtil.checkType
     
    local arguments = {}
    local arguments = {}
     
    local nilArg = {} -- Used for memoizing nil arguments in metaArgs.
    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.
    -- 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)
    local function tidyValDefault(key, val)
    if type(val) == 'string' then
    if type(val) == 'string' then
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    end
    end
    end
    end
     
    local function tidyValTrimOnly(key, val)
    local function tidyValTrimOnly(key, val)
    if type(val) == 'string' then
    if type(val) == 'string' then
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    end
    end
    end
    end
     
    local function tidyValRemoveBlanksOnly(key, val)
    local function tidyValRemoveBlanksOnly(key, val)
    if type(val) == 'string' then
    if type(val) == 'string' then
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    end
    end
    end
    end
     
    local function tidyValNoChange(key, val)
    local function tidyValNoChange(key, val)
    return val
    return val
    end
    end
     
    function arguments.getArgs(frame, options)
    function arguments.getArgs(frame, options)
    checkType('getArgs', 1, frame, 'table', true)
    checkType('getArgs', 1, frame, 'table', true)
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    frame = frame or {}
    frame = frame or {}
    options = options 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 assign the args to a new variable so we can differentiate them.
    -- 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.
    --]]
    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
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    luaArgs = frame
    luaArgs = frame
    end
    end
     
    -- Set up the args and metaArgs tables. args will be the one accessed from functions, and metaArgs will hold the actual arguments.
    -- Set up the args and metaArgs tables. args will be the one accessed from
    -- The metatable connects the two together.
    -- functions, and metaArgs will hold the actual arguments. The metatable
    -- connects the two together.
    local args, metaArgs, metatable = {}, {}, {}
    local args, metaArgs, metatable = {}, {}, {}
    setmetatable(args, 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.
    -- 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
    local tidyVal = options.valueFunc
    if tidyVal then
    if tidyVal then
    if type(tidyVal) ~= 'function' then
    if type(tidyVal) ~= 'function' then
    error("bad value assigned to option 'valueFunc' (function expected, got " .. type(tidyVal) .. ')', 2)
    error(
    "bad value assigned to option 'valueFunc'"
    .. '(function expected, got '
    .. type(tidyVal)
    .. ')',
    2
    )
    end
    end
    elseif options.trim ~= false then
    elseif options.trim ~= false then
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    end
    end
    end
    end
     
    local function mergeArgs(iterator, tables)
    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 precedence.
    -- Accepts multiple tables as input and merges their keys and values
    -- We are also memoizing nil values, but those values can be overwritten.
    -- 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 _, 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
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    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,
    -- Set the order of precedence of the argument tables. If the variables are
    -- which is how we avoid clashes between the frame/parent args and the Lua args.
    -- 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}
    local argTables = {fargs}
    argTables[#argTables + 1] = pargs
    argTables[#argTables + 1] = pargs
    argTables[#argTables + 1] = luaArgs
    argTables[#argTables + 1] = luaArgs
     
    --[[
    --[[
    -- Define metatable behaviour. Arguments are memoized in the metaArgs table, and are only fetched from the
    -- Define metatable behaviour. Arguments are memoized in the metaArgs table,
    -- argument tables once. Nil arguments are also memoized using the nilArg variable in order to increase
    -- and are only fetched from the argument tables once. Nil arguments are
    -- performance. Also, we keep a record in the metatable of when pairs and ipairs have been called, so we
    -- also memoized using the nilArg variable in order to increase performance.
    -- do not run pairs and ipairs on fargs and pargs more than once. We also do not run ipairs on fargs and
    -- Also, we keep a record in the metatable of when pairs and ipairs have
    -- pargs if pairs has already been run, as all the arguments will already have been copied over.
    -- 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)
    metatable.__index = function (t, key)
    local val = metaArgs[key]
    local val = metaArgs[key]
    if val ~= nil then
    if metatable.donePairs or val ~= nil then
    --[[
    -- We have either memoized the argument already, or pairs has been
    -- called, meaning that mergeArgs has already copied all of the
    -- 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
    if val == nilArg then
    return nil
    return nil
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    return nil
    return nil
    end
    end
     
    metatable.__newindex = function (t, key, val)
    metatable.__newindex = function (t, key, val)
    if options.readOnly then
    if options.readOnly then
    error('could not write to argument table key "' .. tostring(key) .. '"; the table is read-only', 2)
    error(
    'could not write to argument table key "'
    .. tostring(key)
    .. '"; the table is read-only',
    2
    )
    elseif options.noOverwrite and args[key] ~= nil then
    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)
    error(
    'could not write to argument table key "'
    .. tostring(key)
    .. '"; overwriting existing arguments is not permitted',
    2
    )
    elseif val == nil then
    elseif val == nil then
    metaArgs[key] = nilArg -- Memoize nils.
    metaArgs[key] = nilArg -- Memoize nils.
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    end
    end
    end
    end
     
    metatable.__pairs = function ()
    metatable.__pairs = function ()
    if not metatable.donePairs then
    if not metatable.donePairs then
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    end
    end
    end
    end
     
    metatable.__ipairs = function ()
    metatable.__ipairs = function ()
    if not metatable.doneIpairs then
    if not metatable.doneIpairs then
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    end, nil, 0
    end, nil, 0
    end
    end
     
    return args
    return args
    end
    end
     
    return arguments
    return arguments
    Retrieved from "https://nonbinary.wiki/wiki/Module:Arguments"