modlib/func.lua

236 lines
4.3 KiB
Lua
Raw Normal View History

-- Localize globals
2022-01-18 18:47:38 +01:00
local error, coroutine, math, modlib, unpack, select, setmetatable
= error, coroutine, math, modlib, unpack, select, setmetatable
2021-06-17 19:45:08 +02:00
-- Set environment
local _ENV = {}
setfenv(1, _ENV)
2020-12-20 15:21:03 +01:00
no_op = function() end
2020-03-23 20:20:43 +01:00
function curry(func, ...)
2020-12-20 15:21:03 +01:00
local args = { ... }
return function(...) return func(unpack(args), ...) end
end
function curry_tail(func, ...)
local args = { ... }
2021-04-01 12:48:06 +02:00
return function(...) return func(unpack(modlib.table.concat({...}, args))) end
2020-12-20 15:21:03 +01:00
end
2021-07-03 11:55:14 +02:00
function curry_full(func, ...)
local args = { ... }
return function() return func(unpack(args)) end
end
function args(...)
2020-12-20 15:21:03 +01:00
local args = { ... }
return function(func) return func(unpack(args)) end
end
function value(val) return function() return val end end
function values(...)
local args = { ... }
return function() return unpack(args) end
end
2022-01-18 18:47:38 +01:00
function memoize(func)
return setmetatable({}, {
__index = function(self, key)
local value = func(key)
self[key] = value
return value
end,
__call = function(self, arg)
return self[arg]
end,
__mode = "k"
})
end
2021-08-08 23:32:50 +02:00
-- Equivalent to `for x, y, z in iterator, state, ... do callback(x, y, z) end`
function iterate(callback, iterator, state, ...)
local function loop(...)
if ... == nil then return end
callback(...)
return loop(iterator(state, ...))
2021-07-03 11:55:36 +02:00
end
2021-08-08 23:32:50 +02:00
return loop(iterator(state, ...))
2021-07-03 11:55:36 +02:00
end
2021-07-14 10:26:57 +02:00
function for_generator(caller, ...)
local co = coroutine.create(function(...)
return caller(function(...)
return coroutine.yield(...)
end, ...)
end)
local args = {...}
return function()
if coroutine.status(co) == "dead" then
return
end
local function _iterate(status, ...)
if not status then
error((...))
end
return ...
end
return _iterate(coroutine.resume(co, unpack(args)))
end
end
2021-07-03 11:55:36 +02:00
-- Does not use select magic, stops at the first nil value
function aggregate(binary_func, total, ...)
if total == nil then return end
local function _aggregate(value, ...)
if value == nil then return end
total = binary_func(total, value)
return _aggregate(...)
end
_aggregate(...)
return total
end
2021-11-13 17:58:40 +01:00
--+ For all functions which aggregate over single values, use modlib.table.ivalues - not ipairs - for lists!
--+ Otherwise they will be applied to the indices.
iterator = {}
function iterator.aggregate(binary_func, total, ...)
for value in ... do
total = binary_func(total, value)
end
return total
end
function iterator.min(less_than_func, ...)
local min
for value in ... do
if min == nil or less_than_func(value, min) then
min = value
end
end
return min
end
function iterator.count(...)
local count = 0
for _ in ... do
count = count + 1
end
return count
end
function iterator.sum(...)
return iterator.aggregate(add, ...)
end
function iterator.average(...)
local count = 0
local sum = 0
for value in ... do
count = count + 1
sum = sum + value
end
return sum / count
end
--: ... **restartable** iterator
-- While a single pass method for calculating the standard deviation exists, it is highly inaccurate
function iterator.standard_deviation(...)
local avg = iterator.average(...)
local count = 0
local sum = 0
for value in ... do
count = count + 1
sum = sum + (value - avg)^2
end
return math.sqrt(sum / count)
end
2020-12-20 15:21:03 +01:00
function override_chain(func, override)
return function(...)
func(...)
return override(...)
end
end
2021-03-22 18:17:26 +01:00
--+ Calls func using the provided arguments, deepcopies all arguments
function call_by_value(func, ...)
return func(unpack(modlib.table.deepcopy{...}))
2021-06-08 14:56:51 +02:00
end
-- Functional wrappers for Lua's builtin metatable operators (arithmetic, concatenation, length, comparison, indexing, call)
function add(a, b)
return a + b
end
function mul(a, b)
return a * b
end
function div(a, b)
return a / b
end
function mod(a, b)
return a % b
end
function pow(a, b)
return a ^ b
end
function unm(a)
return -a
end
function concat(a, b)
return a .. b
end
function len(a)
return #a
end
function eq(a, b)
return a == b
end
function lt(a, b)
return a < b
end
function le(a, b)
return a <= b
end
function index(object, key)
return object[key]
end
function newindex(object, key, value)
object[key] = value
end
function call(object, ...)
object(...)
end
-- Functional wrappers for logical operators, suffixed with _ to avoid a syntax error
function not_(a)
return not a
end
function and_(a, b)
return a and b
end
function or_(a, b)
return a or b
2021-06-17 19:45:08 +02:00
end
-- Export environment
return _ENV