100 lines
2.0 KiB
AppleScript
100 lines
2.0 KiB
AppleScript
-- Y COMBINATOR
|
|
|
|
on |Y|(f)
|
|
script
|
|
on lambda(y)
|
|
script
|
|
on lambda(arg)
|
|
y's lambda(y)'s lambda(arg)
|
|
end lambda
|
|
end script
|
|
|
|
f's lambda(result)
|
|
|
|
end lambda
|
|
end script
|
|
|
|
result's lambda(result)
|
|
end |Y|
|
|
|
|
|
|
-- TEST
|
|
on run
|
|
|
|
-- Factorial
|
|
script fact
|
|
on lambda(f)
|
|
script
|
|
on lambda(n)
|
|
if n = 0 then return 1
|
|
n * (f's lambda(n - 1))
|
|
end lambda
|
|
end script
|
|
end lambda
|
|
end script
|
|
|
|
|
|
-- Fibonacci
|
|
script fib
|
|
on lambda(f)
|
|
script
|
|
on lambda(n)
|
|
if n = 0 then return 0
|
|
if n = 1 then return 1
|
|
(f's lambda(n - 2)) + (f's lambda(n - 1))
|
|
end lambda
|
|
end script
|
|
end lambda
|
|
end script
|
|
|
|
{facts:map(|Y|(fact), range(0, 11)), fibs:map(|Y|(fib), range(0, 20))}
|
|
|
|
--> {facts:{1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800},
|
|
--> fibs:{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765}}
|
|
|
|
end run
|
|
|
|
|
|
---------------------------------------------------------------------------
|
|
|
|
|
|
-- GENERIC FUNCTIONS (FOR TEST)
|
|
|
|
-- map :: (a -> b) -> [a] -> [b]
|
|
on map(f, xs)
|
|
tell mReturn(f)
|
|
set lng to length of xs
|
|
set lst to {}
|
|
repeat with i from 1 to lng
|
|
set end of lst to lambda(item i of xs, i, xs)
|
|
end repeat
|
|
return lst
|
|
end tell
|
|
end map
|
|
|
|
-- range :: Int -> Int -> [Int]
|
|
on range(m, n)
|
|
if n < m then
|
|
set d to -1
|
|
else
|
|
set d to 1
|
|
end if
|
|
set lst to {}
|
|
repeat with i from m to n by d
|
|
set end of lst to i
|
|
end repeat
|
|
return lst
|
|
end range
|
|
|
|
-- Lift 2nd class handler function into 1st class script wrapper
|
|
-- mReturn :: Handler -> Script
|
|
on mReturn(f)
|
|
if class of f is script then
|
|
f
|
|
else
|
|
script
|
|
property lambda : f
|
|
end script
|
|
end if
|
|
end mReturn
|