On 02/04/2013 06:36 AM, Andrei Alexandrescu wrote:
On 2/3/13 11:31 PM, Jonathan M Davis wrote:
I tend to agree that making the parens change the nature of the
expression is a bad idea.
I think there's some misunderstanding here.
Agreed.
Parens change the nature of expressions ALL the time.
In D? No way.
Precedence rules are introduced in order to make parens _implicit_.
In a language with unary & and binary ., There are two possible
interpretations for &a.b:
(&a).b
&(a.b)
In the case of D, &a.b is just a shortcut for &(a.b). How can they
denote different things?
There is a weird rule in C++11 that makes sometimes typeof(expr) and
typeof((expr)) mean different things.
There is also the argument-dependent name lookup thing
namespace bar{
struct S{} baz;
S foo(S x){ return x; }
}
int main(){
foo(bar::baz); // Koenig lookup finds bar::foo
(foo)(bar::baz); // no Koenig lookup, foo undefined
}
Not examples to follow.
That is arguably an example to
avoid. But introducing parens among parts of an expression is expected
to affect meaning.
Sure, but that is not what happens here at all. The parens are
introduced around ONE part of the expression.
