On 03/23/2010 09:12 PM, Steven Schveighoffer wrote:
Andrei Alexandrescu Wrote:
On 03/23/2010 03:46 PM, Steven Schveighoffer wrote:
A while back, you identified one of the best interfaces for input ranges:
E* getNext();
Which allows for null returns when no data is left. The drawback is that
E must be either referenced or allocated on the heap (providing storage
to the function is an option). But the killer issue was that safeD would
not allow it. However, in recent times, you have hinted that safeD may
allow pointers, but disallow bad pointer operations. In light of this,
can we reconsider this interface, or other alternatives using pointers?
I've always felt that if we were to define ranges for streams in a
non-awkward way, we would need an "all in one" operation, since not only
does getting data from the range move the range, but checking for empty
might also move the range (empty on a stream means you tried to read and
got nothing).
I'd gladly reconsider E* getNext(), and I like it a lot, but that
doesn't accommodate ranges that want to return rvalues without storing
them (e.g. a range using getchar() as a back-end, and generally streams
that don't correspond to stuff stored in memory). If it's not in memory,
there's no pointer to it.
First, a range backed by getchar is about as useful as functional qsort ;)
Actually I need one. Think fscanf, i.e. unformat() for streams.
Andrei
