ClarkeRemy

//! this library is largely "incorrect" in the sense that projectors should be exitentials and not part of type arguments
// https://hackage.haskell.org/package/multiplate-0.0.3/docs/src/Data-Generics-Multiplate.html


use std::{marker::PhantomData};

pub trait Funct {
    type F<T>;
}

ClarkeRemy

use std::marker::PhantomData;

// CONTRAVARIANT
struct Contra<'contra> (PhantomData<
  fn(&'contra ()) -> ()
>);
// succeeds (contravariant "lengthening")
fn contra_1<'a>( contra : Contra<'a>) -> Contra<'static> {
  contra
}

ClarkeRemy

type 'a list= List of { l : 'z . (unit -> 'z) -> ('a * 'a list -> 'z) -> 'z }

let nil : 'a list = List{ l = fun f -> fun _ -> f()}
let cons (v : 'a) (r : 'a list) : 'a list= 
    List{ l = fun _ -> fun f -> f(v,r) }

let ex : int list = cons 3 (cons 1 (cons 2 nil))


let length (l : 'a list) : int =

ClarkeRemy

fAtoB_optionA_optionB(_, none, none).
fAtoB_optionA_optionB(F, option(A), option(B)) :- C =.. [F,A,B], C.

functor_map(option, fAtoB_optionA_optionB).

fmapAtoB_fA_fB(Func, F_A, F_B) :-
    ( nonvar(F_A) -> F_A =.. [F| _]
    ; nonvar(F_B) -> F_B =.. [F| _]
    ),
    functor_map(F, Map),

ClarkeRemy

use std::marker::PhantomData;

/// We limit the size of a node to u16::MAX. If you want bigger, make a tree or use a Tensor
pub type Mem    = u16;
pub type Offset = usize;

type InternalHandleRepr = u32;
struct InternalHandle<T>{handle : InternalHandleRepr, _boo : PhantomData<T>}

pub type   ExtHandleRepr = u64;

ClarkeRemy

datatype 'a Tree = 
    Leaf 
  | Branch of {value : 'a, left : 'a Tree, right : 'a Tree}


fun flatten t = case t of
  Leaf => []
| Branch {value, left, right} => let

ClarkeRemy

// https://docs.rs/rust2fun/latest/src/rust2fun/combinator.rs.html#399-417


trait Rec<T, R> {
    fn apply(&self, x: T) -> R;
}

impl<T, R, F> Rec<T, R> for F
where
    F: Fn(&dyn Rec<T, R>, T) -> R,

ClarkeRemy

use core::ops::ControlFlow;
use std::{marker::PhantomData, sync::Arc};


// HKT

#[allow(non_camel_case_types)]
pub type a_<'a, F, T> = <F as A_Funct>::F<'a, T>;
#[allow(non_camel_case_types)]

ClarkeRemy

datatype expr = PLUS of expr * expr 
              | NUM  of int

fun eval_expr (NUM n)      = n
  | eval_expr (PLUS (l,r)) = eval_expr l + eval_expr r

fun pretty_expr (NUM n)      = Int.toString n
  | pretty_expr (PLUS (l,r)) = "( " ^ pretty_expr l ^ " + " ^ pretty_expr r ^ " )"

ClarkeRemy

fun y f x = f (y f) x


functor Fix(type 'a f )
= struct
  type 'a f = 'a f
  datatype fix = FIX of fix f
  fun inj      v  = FIX v
  fun prj (FIX v) = v
  end