On 2/4/13 9:25 AM, Timon Gehr wrote:
On 02/04/2013 03:05 PM, Andrei Alexandrescu wrote:
I think the sensible disambiguation is to
have &fun take the address of fun and the other two take the address of
fun's result.
No! &fun and &(fun) are the same thing. Functions that get their address
taken are not implicitly invoked. (Again, Scala agrees.)
The rules are straightforward:
A non-@property function name 'foo' denotes a function invocation
without arguments iff it does not occur in one of the following contexts:
1. foo(...) // explicitly called
2. &foo // address taken
3. ...!(...,foo,...) // template argument (well, that's what DMD
currently does)
4. alias ... = foo; // aliased
The problem with (3) is that it creates a rule that gives different
meaning of expressions inside &(...) and outside it. Consider:
&foo -> fine, takes the address of foo
&(foo) -> parens don't matter, sweet, still takes the address of foo
&( condition ? foo : bar ) -> hum, I guess takes the address of foo or bar
&( { auto a = foo; ... return c ? foo : bar; }() ) -> what???
So this is essentially a rule that makes the same give expression have a
meaning inside &( ... ) and a different meaning outside.
In &expr.name and &(expr.name), that's it - expr may be arbitrarily
complicated, but the construct must always end with a method name. In
&name and &(name), it's even simpler - it's just punctuation.
Andrei
