Enums

Contents

• Overview
• Basic Usage
• Enum Cases
• Attributes and XML Documentation

#r "../../src/Fabulous.AST/bin/Release/netstandard2.1/publish/Fantomas.Core.dll"
#r "../../src/Fabulous.AST/bin/Release/netstandard2.1/publish/Fabulous.AST.dll"
#r "../../src/Fabulous.AST/bin/Release/netstandard2.1/publish/Fantomas.FCS.dll"

open Fabulous.AST
open type Fabulous.AST.Ast

Overview

An enumeration is a type with a fixed set of named integer constants. Build one with Enum and one EnumCase per value.

Basic Usage

Oak() {
    AnonymousModule() {
        Enum("Color") {
            EnumCase("Red", Int(0))
            EnumCase("Green", Int(1))
            EnumCase("Blue", Int(2))
        }
    }
}
|> Gen.mkOak
|> Gen.run
|> printfn "%s"

// produces the following code:

type Color =
    | Red = 0
    | Green = 1
    | Blue = 2

Enum Cases

Each case pairs a name with a constant value. The value can be a constant widget (Int, Char, ...) or a full ConstantExpr:

Oak() {
    AnonymousModule() {
        Enum("FileAccess") {
            EnumCase("Read", Int(1))
            EnumCase("Write", Int(2))
            EnumCase("ReadWrite", ConstantExpr(Int 3))
        }
    }
}
|> Gen.mkOak
|> Gen.run
|> printfn "%s"

// produces the following code:

type FileAccess =
    | Read = 1
    | Write = 2
    | ReadWrite = 3

Attributes and XML Documentation

Add attributes and documentation with the unified modifiers:

Oak() {
    AnonymousModule() {
        Enum("Color") {
            EnumCase("Red", Int(0))
            EnumCase("Green", Int(1))
            EnumCase("Blue", Int(2))
        }
        |> _.attribute(Attribute("Flags"))
        |> _.xmlDocs([ "The primary colors" ])
    }
}
|> Gen.mkOak
|> Gen.run
|> printfn "%s"

// produces the following code:

/// The primary colors
[<Flags>]
type Color =
    | Red = 0
    | Green = 1
    | Blue = 2