Type IDs

type_id_store.zig

const std = @import("std");

pub const TypeIdStore = struct {
    types: []const type = &.{},

    pub fn id(comptime store: *TypeIdStore, comptime T: type) u32 {
        inline for (store.types, 0..) |t, i| {
            if (t == T) return @intCast(i);
        }

        store.types = store.types ++ &[1]type{T};
        return store.types.len - 1;
    }
};

test {
    comptime var store = TypeIdStore{};
    try std.testing.expectEqual(0, comptime store.id(u8));
    try std.testing.expectEqual(1, comptime store.id(u16));
    try std.testing.expectEqual(0, comptime store.id(u8));
}