HaxeDoc2

Type: EnumValue

EnumValue is a special type which unifies with all enum instances. It is used by the Haxe

Standard Library to provide certain operations for all enum instances and can be employed

in user-code accordingly in cases where an API requiresanenum instance, but not a specific

one.

It is important to distinguish enum types and enum constructors, as this example demon-
strates:
1 enum Color {
2 Red;
3 Green;
4 Blue;
5 Rgb(r:Int, g:Int, b:Int);
6 }
7
8 class Main {
9 static public function main() {
10 var ec:EnumValue = Red; // valid
11 var en:Enum=Color; //valid
12 // Error: Color should be Enum
13 //var x:Enum = Red;
14 }
15 }

If the commented line is uncommented, the program does not compile becauseRed(an enum

constructor) cannot be assigned to a variable of typeEnum<Color>(an enum type). The relation

is analogous to a class and its instance.

Trivia: Concrete type parameter forEnum<T>

One of the reviewers of this manual was confused about the difference betweenColorand

Enum<Color>in the example above. Indeed, using a concrete type parameter there is point-

less and only serves the purpose of demonstration. Usually we would omit the type there

and let type inference (3.6) deal with it.

However, the inferred type would be different fromEnum<Color>. The compiler infers a

pseudo-type which has the enum constructors as “fields”. As of Haxe 3.2.0, it is not possible

to express this type in syntax but also, it is never necessary to do so.

2.4.2 Using enums

Enums are a good choice if only a finite set of values should be allowed. The individual construc-

tors (2.4.1) then represent the allowed variants and enable the compiler to check if all possible

values are respected. This can be seen here:

1 enum Color {

2 Red;

3 Green;

4 Blue;

5 Rgb(r:Int, g:Int, b:Int);

6 }

7