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

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.

This would be instrumental to creating an ECS library in Zig

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

Awesome. Now I can at least complete my ECS

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

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[Feature Request] @typeInfo of a `type` with a unique identifier #5459

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[Feature Request] @typeInfo of a type with a unique identifier #5459

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mmstick commented on Jun 3, 2021

ikskuh commented on Jun 3, 2021

mmstick commented on Jun 3, 2021

Parallel-Paradox commented on Aug 22, 2023

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[Feature Request] @typeInfo of a `type` with a unique identifier #5459