On 11/29/10 3:38 PM, Bruno Medeiros wrote:
On 20/11/2010 05:31, Walter Bright wrote:
Stewart Gordon wrote:
On 12/11/2010 09:53, Andrei Alexandrescu wrote:
<snip>
Well put me on board then. Walter, please don't forget to tweak the
associativity rules: var ~ " literal " ~ " literal " concatenates
literals first.
You mean make ~ right-associative? I think this'll break more code
than it fixes.
But implementing a compiler optimisation so that var ~ ctc ~ ctc is
processed as var ~ (ctc ~ ctc), _in those cases where they're
equivalent_, would be sensible.
Andrei's right. This is not about making it right-associative. It is
about defining in the language that:
((a ~ b) ~ c)
is guaranteed to produce the same result as:
(a ~ (b ~ c))
Unfortunately, the language cannot make such a guarantee in the face of
operator overloading. But it can do it for cases where operator
overloading is not in play.
So if you have the code:
(a ~ b ~ c)
and b and c are strings, but a is not a string (nor has a toString
method, nor implicit convertion), but has a overload of the append
operator, then b and c will not be joined in compile-time, according to
that?
That is correct. The compiler cannot infer that user-defined ~ is in
fact associative.
Andrei
