3 ms·

`int * A` and `A * int` both seem ambiguous unless a) you require "int-pointer" naming instead of "pointer-int", and/or b) you have a separator (like the title

by Groxx 7y ago

`int * A` and `A * int` both seem ambiguous unless a) you require "int-pointer" naming instead of "pointer-int", and/or b) you have a separator (like the title uses) so this becomes `A * B` vs `A: * B` which is indeed unambiguous but in a very different way. i.e. without extra rules you can't tell either way, so it comes down to the extra rules. `A * B` is unambiguous for type-before-name if you require "pointer-int" since it would need to be `* A B` for A to be a type. (quite possibly there are counter-examples when you get into weirder corners, but my point is that it's not as simple as presented)

WalterBright 7y ago
D resolves the: A * B; // declaration or multiplication? in an unusual way. If it was a multiplication, the result would be thrown away and be pointless. Hence, it is a declaration. But what if A overloads the * operator and the side effects are desired rather than the result? D has a philosophy that arithmetic overloads should be for arithmetic-like operations, not I/O, template metaprogramming, or other nonsense. Hence if you try it like that, too bad, so sad, it'll be treated as a declaration.
- Ididntdothis 7y ago
  I wouldn’t mind if such a statement in isolation would be a compiler error and if languages in general were much stricter. So far all languages I have seen that are very forgiving in terms of syntax (PHP comes to mind) seem to breed sloppy programmers and software written in these often have stupid little bugs caused by typos.
  - WalterBright 7y ago
    This particular issue has not caused any "silly typo disease" problems that I'm aware of in D. In fact, pretty much nobody notices it, it just works the way people expect it to. (There are some other things in D that are designed to discourage trying to overload arithmetic operators for non-arithmetic purposes. For example, < <= > >= cannot be overloaded individually, only as a group.)

by Groxx 7y ago

WalterBright 7y ago

D resolves the: A * B; // declaration or multiplication? in an unusual way. If it was a multiplication, the result would be thrown away and be pointless. Hence, it is a declaration. But what if A overloads the * operator and the side effects are desired rather than the result? D has a philosophy that arithmetic overloads should be for arithmetic-like operations, not I/O, template metaprogramming, or other nonsense. Hence if you try it like that, too bad, so sad, it'll be treated as a declaration.

Ididntdothis 7y ago
I wouldn’t mind if such a statement in isolation would be a compiler error and if languages in general were much stricter. So far all languages I have seen that are very forgiving in terms of syntax (PHP comes to mind) seem to breed sloppy programmers and software written in these often have stupid little bugs caused by typos.
- WalterBright 7y ago
  This particular issue has not caused any "silly typo disease" problems that I'm aware of in D. In fact, pretty much nobody notices it, it just works the way people expect it to. (There are some other things in D that are designed to discourage trying to overload arithmetic operators for non-arithmetic purposes. For example, < <= > >= cannot be overloaded individually, only as a group.)