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Alternative to using spaces in discriminated union cases

This shows an alternative to using spaces in the discriminated union cases, which makes it harder to write in code, and tends to be needed when interoping with the likes of WPF or any other element that uses the ToString of the union case to display its value. Also useful as an alternative to using special characters like á or ç which make it harder to work with colleagues that don't have keyboards with those characters. Uses code from snippet http://fssnip.net/9l

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open Microsoft.FSharp.Reflection

let toString (x:'a) = 
    match FSharpValue.GetUnionFields(x, typeof<'a>) with
    | case, _ -> case.Name

type SpecialCharactersUnion = 
    | Ola
    | Nao
    | RegularCharactersButWithSpaces
    | Normal
    override this.ToString() =
        match this with
        | Ola -> "Olá"
        | Nao -> "Não"
        | RegularCharactersButWithSpaces -> "Regular Characters But With Spaces"
        | _ -> toString this

//Usage:
// Everytime a union case tostring gets called, the special cases will override it and present a string with the special characters.

namespace Microsoft

namespace Microsoft.FSharp

namespace Microsoft.FSharp.Reflection

val toString : x:'a -> string

Full name: Script.toString

val x : 'a

type FSharpValue =
  static member GetExceptionFields : exn:obj * ?bindingFlags:BindingFlags -> obj []
  static member GetRecordField : record:obj * info:PropertyInfo -> obj
  static member GetRecordFields : record:obj * ?bindingFlags:BindingFlags -> obj []
  static member GetTupleField : tuple:obj * index:int -> obj
  static member GetTupleFields : tuple:obj -> obj []
  static member GetUnionFields : value:obj * unionType:Type * ?bindingFlags:BindingFlags -> UnionCaseInfo * obj []
  static member MakeFunction : functionType:Type * implementation:(obj -> obj) -> obj
  static member MakeRecord : recordType:Type * values:obj [] * ?bindingFlags:BindingFlags -> obj
  static member MakeTuple : tupleElements:obj [] * tupleType:Type -> obj
  static member MakeUnion : unionCase:UnionCaseInfo * args:obj [] * ?bindingFlags:BindingFlags -> obj
  ...

Full name: Microsoft.FSharp.Reflection.FSharpValue

static member FSharpValue.GetUnionFields : value:obj * unionType:System.Type * ?allowAccessToPrivateRepresentation:bool -> UnionCaseInfo * obj []
static member FSharpValue.GetUnionFields : value:obj * unionType:System.Type * ?bindingFlags:System.Reflection.BindingFlags -> UnionCaseInfo * obj []

val typeof<'T> : System.Type

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

val case : UnionCaseInfo

property UnionCaseInfo.Name: string

type SpecialCharactersUnion =
  | Ola
  | Nao
  | RegularCharactersButWithSpaces
  | Normal
  override ToString : unit -> string

Full name: Script.SpecialCharactersUnion

union case SpecialCharactersUnion.Ola: SpecialCharactersUnion

union case SpecialCharactersUnion.Nao: SpecialCharactersUnion

union case SpecialCharactersUnion.RegularCharactersButWithSpaces: SpecialCharactersUnion

union case SpecialCharactersUnion.Normal: SpecialCharactersUnion

val this : SpecialCharactersUnion

override SpecialCharactersUnion.ToString : unit -> string

Full name: Script.SpecialCharactersUnion.ToString

Raw view Test code New version

More information

Link:	http://fssnip.net/7VN
Posted:	6 years ago
Author:	Micael Morais
Tags:	discriminated union