[Request] Provide a way to enumerate all values in an enum

General Feedback & Requests
, ,
1

Background

It is quite convenient that case statements can check that all values in the enum are covered, for example:

attack := enum:
    Beam
    Missile

GetDamage(Attack: attack):float=
    case (Attack):
        attack.Beam => 100.0
        attack.Missile => 500.0

If I add a new value to the enum above, Verse will tell me that case needs to handle it.

Problem

However let’s say I want to iterate through all values:

for (Attack: array { attack.Beam, attack.Missile }):
    SetupAttack(Attack)

in this case, if a new value is added to the original enum, it will not be covered in the iteration.

Proposal

Provide a built-in way to enumerate all values of an enum.
Order can match the order in code.

Some options:

# Option 1: Enumerate the type itself.
#
# Reads a bit awkwardly, but does feel consistent with Verse's design spirit, to the extent I understand https://simon.peytonjones.org/assets/pdfs/haskell-exchange-22.pdf (which is not much).

for (Attack: attack) { ... }

# Option 2: Enumerate through a helper method.

for (Attack: GetEnumElements(attack)) { ... }

# Option 3: Constrain array to require all enum values

AllAttacks := array<exhaustive> { attack.Beam, attack.Missile }
for (Attack: AllAttacks) { ... }