Files
fsharp-vectors/Vector/Vector.fs

81 lines
3.0 KiB
Forth

namespace Vector
open Vector.Naturals
/// A vector with known length.
[<Struct>]
type Vector<'a, 'len> = private | Vector of 'a list
type VectorCrateEvaluator<'a, 'ret> = abstract Eval<'n> : Vector<'a, 'n> -> 'ret
type VectorCrate<'a> = abstract Apply<'ret> : VectorCrateEvaluator<'a, 'ret> -> 'ret
[<RequireQualifiedAccess>]
module VectorCrate =
let make<'a, 'n> (v : Vector<'a, 'n>) : VectorCrate<'a> =
{ new VectorCrate<'a> with
member __.Apply e = e.Eval v
}
[<RequireQualifiedAccess>]
module Vector =
let empty<'a> : Vector<'a, Z> = Vector []
let cons<'a, 'n> (x : 'a) (Vector v : Vector<'a, 'n>) : Vector<'a, S<'n>> =
Vector (x :: v)
let toList<'a, 'n> (Vector v : Vector<'a, 'n>) : 'a list = v
/// This is very inefficient, and I can't imagine it being helpful,
/// but it's here for completeness.
let rec ofList<'a> (v : List<'a>) : VectorCrate<'a> =
match v with
| [] -> VectorCrate.make empty
| x :: xs ->
{ new VectorCrate<'a> with
member __.Apply e =
(ofList xs).Apply
{ new VectorCrateEvaluator<_,_> with
member __.Eval v =
e.Eval (cons x v)
}
}
/// Vector.append v1 v2 is v1 ++ v2. (Which is a bit sad, given how often we would want to pipe this,
/// but it's consistent with List.)
let append<'a, 'n1, 'n2> (Vector v1 : Vector<'a, 'n1>) (Vector v2 : Vector<'a, 'n2>) : Vector<'a, Add<'n1, 'n2>> =
List.append v1 v2
|> Vector
let fold<'a, 's, 'n> (f : 's -> 'a -> 's) (s : 's) (Vector v : Vector<'a, 'n>) =
List.fold f s v
let zip<'a, 'b, 'n> (Vector v1 : Vector<'a, 'n>) (Vector v2 : Vector<'b, 'n>) : Vector<'a * 'b, 'n> =
List.zip v1 v2
|> Vector
let map<'a, 'b, 'n> (f : 'a -> 'b) (Vector v : Vector<'a, 'n>) : Vector<'b, 'n> =
List.map f v
|> Vector
let head<'a, 'n> (Vector v : Vector<'a, S<'n>>) : 'a = List.head v
let tail<'a, 'n> (Vector v : Vector<'a, S<'n>>) : Vector<'a, 'n> = List.tail v |> Vector
[<RequireQualifiedAccess>]
module Unsafe =
let cast<'a, 'n, 'm> (Vector a : Vector<'a, 'n>) : Vector<'a, 'm> = Vector a
/// Allows you to convert safely between Vector<int, 3> and Vector<int, 1 + 2>, say.
/// You may need to call `cast` multiple times.
let inline cast< ^n2, ^n1, 'a when (^n1 or ^n2) : (static member refine : ^n1 -> ^n2)> (a : Vector<'a, ^n1>) : Vector<'a, ^n2> = Unsafe.cast a
let inline cast'< ^n1, ^n2, 'a when (^n1 or ^n2) : (static member refine : ^n1 -> ^n2)> (a : Vector<'a, ^n1>) : Vector<'a, ^n2> = Unsafe.cast a
[<AutoOpen>]
module Patterns =
let (|Vec|) (Vector v : Vector<'a, S<'n>>) : 'a * Vector<'a, 'n> =
List.head v, Vector (List.tail v)
let (|Empty|) (_ : Vector<'a, Z>) = ()
let ( ~- ) () : Vector<'a, Z> = Vector.empty<'a>
let ( ** ) (x : 'a) (v : Vector<'a, 'n>) = Vector.cons x v