FunctionaLang

A functional language that is mostly inspired by SML, although there are a few differences

Differences like

• Patterns (especially as-patterns) work slightly different
• Equality is ==
• Integers have no upper/lower bound (BigInteger)
• Unary - is a minus, too. Note that this does not affect op-
• No datatype definitions in let-in expressions, so we don't open that can of worms.

Example program:

Courtesy of Rosetta code's SML Y combinator

datatype 'a mu = Roll of ('a mu -> 'a)
fun unroll (Roll x) = x;
(fn f => (fn x => fn a => f (unroll x x) a) (Roll (fn x => fn a => f (unroll x x) a)))  (fn f => fn 0=>0|x => x+f(x-1));
it 10;

Output

Roll = Roll : ∀ 'a: ('a mu->'a)->'a mu
unroll = fn : ∀ 'a: 'a mu->'a mu->'a
it = fn : int->int
it = 55 : int