Daniel Keep wrote:


Michel Fortin wrote:
On 2008-12-31 21:50:53 -0500, Daniel Keep <daniel.keep.li...@gmail.com> said:

Disclaimer: I'm not an expert on compilers.  Plus, I just got up.  :P

The key is that the parser has to know what "MyClass" means before it can figure out what the "?" is for; that's why it's context-dependant. D avoids this dependency between compilation stages, because it complicates the compiler. When the parser sees "MyClass", it *doesn't know* that it's a type, so it can't distinguish between a nullable type and an invalid ?: expression.

As far as I know, this can't be done with pointer declarations. Read this:

    a * b;

Is it a multiplication or a declaration of a pointer to type "a"? You don't know until you resolve the identifiers. It's the exact same situation for using "?" to denote nullable.


At least, I think that's how it works; someone feel free to correct me if it's not. :P

I belived the same for some time too, then found the above rebutal.

I don't think so; I believe that unary vs. binary operators are unambiguous. "a * b" is "a multiply b" because it's "(expr) * (expr)". It's pointer dereference when it's "* (expr)".

I keep in mind is that "(expr) < (expr) >" is ambiguous, but "* (expr)" isn't.

Like I said, I'm not an expert, so take what I say with a grain of salt.

  -- Daniel


It's about a pointer declaration, not a pointer dereference, a la "int * p;"

Happy New Year everyone!

Andrei

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