alt Hacker NewsI know language designers have a lot of trade-offs to consider... But I would say if you know a value will logically always be >= 0, better to have a type that reflects that.
The potential bugs listed would be prevented by, e.g. "x--" won't compile without explicitly supplying a case for x==0 OR by using some more verbose methods like "decrement_with_wrap".
The trade-off is lack of C-like concise code, but more safe and explicit.
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mamcx • yesterday at 7:36 PM
I think it should be alike in Pascal where you have size ranges as types, and then, you can declare that this collection fall on this range (and very nicely, you can make it at enum):
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> But I would say if you know a value will logically always be >= 0, better to have a type that reflects that.
Except that's not quite what unsigned types do. They are not (just) numbers that will always be >= 0, but numbers where the value of `1 - 2` is > 1 and depends on the type. This is not an accident but how these types are intended to behave because what they express is that you want modular arithmetic, not non-negative integers.
> e.g. "x--" won't compile without explicitly supplying a case for x==0
If you want non-negative types (which, again, is not what unsigned types are for) you also run into difficulties with `x - y`. It's not so simple.
There are many useful constraints that you might think it's "better to have a type that reflects that" - what about variables that can only ever be even? - but it's often easier said than done.