[Feature Request] @typeInfo of a type with a unique identifier

[prime31]

Currently, there is no way to key a HashMap with a type to make a lookup table. It would be handy if we could get at a unique value to use for this use case: @typeInfo(T).id. If @typeInfo(T).id were unique to each type it would provide the perfect key for a type lookup table.

The current workaround is to use a StringHashMap keyed off of @typeName(T) with the values being auto-incremented ints.

[mmstick]

This would be instrumental to creating an ECS library in Zig

[ikskuh]

There's a workaround that takes up 1 byte of memory per type:

fn typeId(comptime T: type) usize {
    return @ptrToInt(&struct { var x: u8 = 0; }.x);
}

But i'd prefer to have proper @typeId builtin or a field in @typeInfo that solves this use case

[mmstick]

Awesome. Now I can at least complete my ECS

[Parallel-Paradox]

There's a workaround that takes up 1 byte of memory per type:

fn typeId(comptime T: type) usize {
    return @ptrToInt(&struct { var x: u8 = 0; }.x);
}

But i'd prefer to have proper @typeId builtin or a field in @typeInfo that solves this use case

Change @ptrToInt into @intFromPtr after 0.11.0