A simple ML dialect with definitions, let polymorphism and a fixpoint operator. Uses syntax directed HM type inference.
This is a modified version of Stephen Diehl's Poly. https://github.com/sdiehl/write-you-a-haskell/tree/master/chapter7/poly_constraints
This version compiles expressions a finite, fixed set of combinators, and then run these combinators just as Haskell functions.
To compile and run:
$ cabal runUsage:
Poly> let i x = x;
i : forall a. a -> a
Poly> i 3
3
Poly> :type i
i : forall a. a -> a
Poly> :type let k x y = x;
k : forall a b. a -> b -> a
Poly> :type let s f g x = f x (g x)
s : forall a b c. ((a -> b) -> c -> a) -> (a -> b) -> c -> b
Poly> :type let on g f = \x y -> g (f x) (f y)
on : forall a b c. (a -> a -> b) -> (c -> a) -> c -> c -> b
Poly> :type let let_bound = i (i i) (i 3)
let_bound : Int
Poly> :type let compose f g = \x -> f (g x)
compose : forall a b c. (a -> b) -> (c -> a) -> c -> b
Poly> let rec factorial n =
if (n == 0)
then 1
else (n * (factorial (n-1)));Top level let declarations are syntactic sugar for nested lambda. For example:
let add x y = x + y;Is semantically equivalent to:
let add = \x -> \y -> x + y;Top level Let-rec declarations are syntactic sugar for use of the fix
operator. For example:
let rec factorial n = if (n == 0) then 1 else (n * (factorial (n-1)));Is semantically equivalent to:
let factorial = fix (\factorial n -> if (n == 0) then 1 else (n * (factorial (n-1))));Released under MIT license.
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent