Non-nullable references, again
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Wed Dec 31 23:17:13 PST 2008
Daniel Keep wrote:
> Michel Fortin wrote:
>> On 2008-12-31 21:50:53 -0500, Daniel Keep
>> <daniel.keep.lists at 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
>> 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)"
> 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!
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