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type [<Measure>] b
 
type Vec<'a, [<Measure>] 'n> = 
    | V of List<'a>
 
let nil<'a> : Vec<'a, 1> =
    V([])
 
let cons (x : 'a) (V(xs) : Vec<'a,'n>) : Vec<'a,'n b> =
    V(x :: xs)
 
let append (V(xs) : Vec<'a,'n>) (V(ys) : Vec<'a,'m>) : Vec<'a,'n 'm> =
    V(xs @ ys)
 
let zip (V(xs) : Vec<'a,'n>) (V(ys) : Vec<'b,'n>) : Vec<'a * 'b,'n> =
    V(List.zip xs ys)
 
let sum (V(xs) : Vec<int,'n>) : int = 
    List.sum xs
 
let l = cons 1 (cons 2 (cons 3 nil))
let g = zip l l

(*
error FS0001: Type mismatch. Expecting a
    Vec<int,1>    
but given a
    Vec<int,b ^ 3>    
The unit of measure '1' does not match the unit of measure 'b ^ 3' 
*)
//let h = zip l (append l l)
 
printfn "%A" l
printfn "%A" g

Multiple items
type MeasureAttribute =
inherit Attribute
new : unit -> MeasureAttribute

Full name: Microsoft.FSharp.Core.MeasureAttribute

--------------------
new : unit -> MeasureAttribute

[<Measure>]
type b

Full name: Script.b

type Vec<'a,'n> = | V of List<'a>

Full name: Script.Vec<_,_>

union case Vec.V: List<'a> -> Vec<'a,'n>

Multiple items
module List

from Microsoft.FSharp.Collections

--------------------
type List<'T> =
  | ( [] )
  | ( :: ) of Head: 'T * Tail: 'T list
  interface IEnumerable
  interface IEnumerable<'T>
  member Head : 'T
  member IsEmpty : bool
  member Item : index:int -> 'T with get
  member Length : int
  member Tail : 'T list
  static member Cons : head:'T * tail:'T list -> 'T list
  static member Empty : 'T list

Full name: Microsoft.FSharp.Collections.List<_>

val nil<'a> : Vec<'a,1>

Full name: Script.nil

val cons : x:'a -> Vec<'a,'n> -> Vec<'a,'n b>

Full name: Script.cons

val x : 'a

val xs : List<'a>

val append : Vec<'a,'n> -> Vec<'a,'m> -> Vec<'a,'m 'n>

Full name: Script.append

val ys : List<'a>

val zip : Vec<'a,'n> -> Vec<'b,'n> -> Vec<('a * 'b),'n>

Full name: Script.zip

val ys : List<'b>

val zip : list1:'T1 list -> list2:'T2 list -> ('T1 * 'T2) list

Full name: Microsoft.FSharp.Collections.List.zip

val sum : Vec<int,'n> -> int

Full name: Script.sum

val xs : List<int>

Multiple items
val int : value:'T -> int (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int

--------------------
type int = int32

Full name: Microsoft.FSharp.Core.int

--------------------
type int<'Measure> = int

Full name: Microsoft.FSharp.Core.int<_>

val sum : list:'T list -> 'T (requires member ( + ) and member get_Zero)

Full name: Microsoft.FSharp.Collections.List.sum

val l : Vec<int,b ^ 3>

Full name: Script.l

val g : Vec<(int * int),b ^ 3>

Full name: Script.g

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

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Link:	http://fssnip.net/3Q
Posted:	15 years ago
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