మాడ్యూల్:fun
Documentation for this module may be created at మాడ్యూల్:fun/doc
local export = {}
local ustring = mw.ustring
local libraryUtil = require "libraryUtil"
local checkType = libraryUtil.checkType
local checkTypeMulti = libraryUtil.checkTypeMulti
local iterableTypes = { "table", "string" }
local function _check(funcName, expectType)
if type(expectType) == "string" then
return function(argIndex, arg, nilOk)
return checkType(funcName, argIndex, arg, expectType, nilOk)
end
else
return function(argIndex, arg, expectType, nilOk)
if type(expectType) == "table" then
if not (nilOk and arg == nil) then
return checkTypeMulti(funcName, argIndex, arg, expectType)
end
else
return checkType(funcName, argIndex, arg, expectType, nilOk)
end
end
end
end
-- Iterate over UTF-8-encoded codepoints in string.
local function iterString(str)
local iter = string.gmatch(str, "[%z\1-\127\194-\244][\128-\191]*")
local i = 0
local function iterator()
i = i + 1
local char = iter()
if char then
return i, char
end
end
return iterator
end
function export.chain(func1, func2, ...)
return func1(func2(...))
end
-- map(function(number) return number ^ 2 end,
-- { 1, 2, 3 }) --> { 1, 4, 9 }
-- map(function (char) return string.char(string.byte(char) - 0x20) end,
-- "abc") --> { "A", "B", "C" }
function export.map(func, iterable, isArray)
local check = _check 'map'
check(1, func, "function")
check(2, iterable, iterableTypes)
local array = {}
local iterator = type(iterable) == "string" and iterString
or (isArray or iterable[1] ~= nil) and ipairs or pairs
for i_or_k, val in iterator(iterable) do
array[i_or_k] = func(val, i_or_k, iterable)
end
return array
end
function export.mapIter(func, iter, iterable, initVal)
local check = _check 'mapIter'
check(1, func, "function")
check(2, iter, "function")
check(3, iterable, iterableTypes, true)
-- initVal could be anything
local array = {}
local i = 0
for x, y in iter, iterable, initVal do
i = i + 1
array[i] = func(y, x, iterable)
end
return array
end
function export.forEach(func, iterable, isArray)
local check = _check 'forEach'
check(1, func, "function")
check(2, iterable, iterableTypes)
local iterator = type(iterable) == "string" and iterString
or (isArray or iterable[1] ~= nil) and ipairs or pairs
for i_or_k, val in iterator(iterable) do
func(val, i_or_k, iterable)
end
return nil
end
-------------------------------------------------
-- From http://lua-users.org/wiki/CurriedLua
-- reverse(...) : take some tuple and return a tuple of elements in reverse order
--
-- e.g. "reverse(1,2,3)" returns 3,2,1
local function reverse(...)
-- reverse args by building a function to do it, similar to the unpack() example
local function reverseHelper(acc, v, ...)
if select('#', ...) == 0 then
return v, acc()
else
return reverseHelper(function() return v, acc() end, ...)
end
end
-- initial acc is the end of the list
return reverseHelper(function() return end, ...)
end
function export.curry(func, numArgs)
-- currying 2-argument functions seems to be the most popular application
numArgs = numArgs or 2
-- no sense currying for 1 arg or less
if numArgs <= 1 then return func end
-- helper takes an argTrace function, and number of arguments remaining to be applied
local function curryHelper(argTrace, n)
if n == 0 then
-- kick off argTrace, reverse argument list, and call the original function
return func(reverse(argTrace()))
else
-- "push" argument (by building a wrapper function) and decrement n
return function(onearg)
return curryHelper(function() return onearg, argTrace() end, n - 1)
end
end
end
-- push the terminal case of argTrace into the function first
return curryHelper(function() return end, numArgs)
end
-------------------------------------------------
-- some(function(val) return val % 2 == 0 end,
-- { 2, 3, 5, 7, 11 }) --> true
function export.some(func, t, isArray)
if isArray or t[1] ~= nil then -- array
for i, v in ipairs(t) do
if func(v, i, t) then
return true
end
end
else
for k, v in pairs(t) do
if func(v, k, t) then
return true
end
end
end
return false
end
-- all(function(val) return val % 2 == 0 end,
-- { 2, 4, 8, 10, 12 }) --> true
function export.all(func, t, isArray)
if isArray or t[1] ~= nil then -- array
for i, v in ipairs(t) do
if not func(v, i, t) then
return false
end
end
else
for k, v in pairs(t) do
if not func(v, k, t) then
return false
end
end
end
return true
end
function export.filter(func, t, isArray)
local new_t = {}
if isArray or t[1] ~= nil then -- array
local new_i = 0
for i, v in ipairs(t) do
if func(v, i, t) then
new_i = new_i + 1
new_t[new_i] = v
end
end
else
for k, v in pairs(t) do
if func(v, k, t) then
new_t[k] = v -- or create array?
end
end
end
return new_t
end
function export.fold(func, t, accum)
for i, v in ipairs(t) do
accum = func(accum, v, i, t)
end
return accum
end
-------------------------------
-- Fancy stuff
local function capture(...)
local vals = { n = select('#', ...), ... }
return function()
return unpack(vals, 1, vals.n)
end
end
-- Log input and output of function.
-- Receives a function and returns a modified form of that function.
function export.logReturnValues(func, prefix)
return function(...)
local inputValues = capture(...)
local returnValues = capture(func(...))
if prefix then
mw.log(prefix, inputValues())
mw.log(returnValues())
else
mw.log(inputValues())
mw.log(returnValues())
end
return returnValues()
end
end
export.log = export.logReturnValues
-- Convenience function to make all functions in a table log their input and output.
function export.logAll(t)
for k, v in pairs(t) do
if type(v) == "function" then
t[k] = export.logReturnValues(v, tostring(k))
end
end
return t
end
----- M E M O I Z A T I O N-----
-- metamethod that does the work
-- Currently supports one argument and one return value.
local func_key = {}
local function callMethod(self, x)
local output = self[x]
if not output then
output = self[func_key](x)
self[x] = output
end
return output
end
-- shared metatable
local mt = { __call = callMethod }
-- Create callable table.
function export.memoize(func)
return setmetatable({ [func_key] = func }, mt)
end
-------------------------------
return export