How to enumerate an enum/type in F#

Question

I\'ve got an enumeration type defined like so:

type tags = 
    | ART  = 0
    | N    = 1
    | V    = 2 
    | P    = 3
    | NULL = 4

is

Answer 1

You can use Enum.GetValues, which returns an Array of objects that you then have to downcast to integer values. (Note: I'm using Mono's F# implementation; maybe things are different with .NET.)

Here are some functions I wrote to get a list of all enumeration values and to get the min and max values:

open System

module EnumUtil =

    /// Return all values for an enumeration type
    let EnumValues (enumType : Type) : int list =
        let values = Enum.GetValues enumType
        let lb = values.GetLowerBound 0
        let ub = values.GetUpperBound 0
        [lb .. ub] |> List.map (fun i -> values.GetValue i :?> int) 

    /// Return minimum and maximum values for an enumeration type
    let EnumValueRange (enumType : Type) : int * int =
        let values = EnumValues enumType
        (List.min values), (List.max values)