Jarrett Billingsley wrote:
On Wed, Dec 24, 2008 at 5:24 PM, Yigal Chripun<[email protected]> wrote:
why not replace the current comma operator with tuple support?
the comma op needs to be higher than assingment in precedence and instead of
evaluating the expressions left to right and returning the value of the
_last_ expression as the return value of the op, return _all_ expressions'
return values as a value tuple. the current behavior that is really used
only in for loops can be implemented with tuples as well.
insted of:
for (int i = 0, long j = 0; ...; ...) {...}
Actually that's not legal syntax. You're thinking of "int i = 0, j =
0", which is parsed as a single declaration statement which declares
two variables. This does not use the comma operator.
The place where the comma operator is used is in the increment:
for(..; ..; i++, j++)
All that has to be done here is the comma has to be added to the
increment grammar of the for loop. (MiniD does this.)
and what if I do instead:
int i; long j;
for (i = 0, j = 0; ...; ++i, ++j) {...}
that should be legal, right? I don't use this feature that often....
I was trying to suggest a more general solution rather than adding a
special case for "for" loops. IMO, with proper tuple support you do not
need special cases. i.e.:
(++i, ++j) is a regular tuple that given i = 2 and j = 5 will evaluate
to (3, 6) which can be assinged to the loop variable:
for (Tuple!(int, long) (a, b) = (0, 1); cond; (++a, ++b)) {...}
