modlib/func.lua
2022-09-30 16:09:16 +02:00

126 lines
2.6 KiB
Lua

-- Localize globals
local modlib, unpack, select, setmetatable
= modlib, unpack, select, setmetatable
-- Set environment
local _ENV = {}
setfenv(1, _ENV)
function no_op() end
function identity(...) return ... end
-- TODO switch all of these to proper vargs
function curry(func, ...)
local args = { ... }
return function(...) return func(unpack(args), ...) end
end
function curry_tail(func, ...)
local args = { ... }
return function(...) return func(unpack(modlib.table.concat({...}, args))) end
end
function curry_full(func, ...)
local args = { ... }
return function() return func(unpack(args)) end
end
function args(...)
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
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
function compose(func, other_func)
return function(...)
return func(other_func(...))
end
end
function override_chain(func, override)
return function(...)
func(...)
return override(...)
end
end
--+ Calls func using the provided arguments, deepcopies all arguments
function call_by_value(func, ...)
return func(unpack(modlib.table.deepcopy{...}, 1, select("#", ...)))
end
-- Functional wrappers for Lua's builtin metatable operators (arithmetic, concatenation, length, comparison, indexing, call)
-- TODO (?) add operator table `["+"] = add, ...`
function add(a, b) return a + b end
function sub(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 neq(a, b) return a ~= b end
function lt(a, b) return a < b end
function gt(a, b) return a > b end
function le(a, b) return a <= b end
function ge(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 _ for syntactical convenience
function not_(a) return not a end
_ENV["not"] = not_
function and_(a, b) return a and b end
_ENV["and"] = and_
function or_(a, b) return a or b end
_ENV["or"] = or_
-- Export environment
return _ENV