Enums

Named constants with underlying values, introspectable as a group.

An enum declares a set of named constants. Each name becomes a value you can use directly; by default the names take integer values counting from zero.

Declaring an enum #

enum Color <Red Green Blue>;
say Red;
say Green.value;
say Blue.value;

Red
1
2

Red, Green, Blue are usable as bare terms. .value gives the underlying number — Red is 0, Green is 1, Blue is 2.

Introspecting the group #

The enum type knows all its members. .enums returns them as a name-to-value map.

enum Suit <hearts diamonds clubs spades>;
say hearts.value;
say Suit.enums.sort;

0
(clubs => 2 diamonds => 1 hearts => 0 spades => 3)

Notes #

• Assign explicit values with pairs: enum HttpStatus (OK => 200, NotFound => 404).
• An enum value knows its name (.key) and number (.value), and stringifies to its name — which is why say Red prints Red, not 0.
• Enum names are ordinary constants in scope, so they smartmatch in when clauses and compare with ==/cmp.