On Monday, 24 March 2014 at 09:13:39 UTC, ponce wrote:
On Monday, 24 March 2014 at 09:09:30 UTC, monarch_dodra wrote:
//----
for (size_t i, j ; someCondition() ; ++i, ++j )
{...}
//----
I think this is *the* single most common use of operator
comma, and I also think it is perfectly legit. Sure, it can
easily be migrated away from, but I think it would be
gratuitous breakage of good code.
Legit but largely useless.
In every cases I've seen where this idiom appears, you can
derive j from i and the compiler is able to generate the very
same code.
I've seen plenty of cases where you can't, such as most
algorithms that "copy filter" or "copy remove". Further,
especially with ranges, you can't derive one from the other. The
code usually becomes:
for ( ; someCondition() ; r1.popFront(), r2.popFront() )
