On 1/17/11 11:48 PM, Jonathan M Davis wrote:
On Monday 17 January 2011 15:13:42 spir wrote:See range bug evoked above. opApply is the only workaround AFAIK. Also, ranges cannot yet provide indexed iteration like foreach(i, char ; text) {...}While it would be nice at times to be able to have an index with foreach when using ranges, I would point out that it's trivial to just declare a variable which you increment each iteration, so it's easy to get an index even when using foreach with ranges. Certainly, I wouldn't consider the lack of index with foreach and ranges a good reason to use opApply instead of ranges. There may be other reasons which make it worthwhile, but it's so trivial to get an index that the loss of range abilities (particularly the ability to use such ranges with std.algorithm) dwarfs it in importance. - Jonathan M Davis
It's a bit more difficult than that. When iterating a variable-length encoded range, what you need more than the current item being iterated is the physical offset reached inside the range. That's not all that difficult either as the range can always provide an extra primitive, but a bit annoying (e.g. because it makes iteration with foreach impossible if you want the index, unless you return a tuple with each step).
At any rate, I agree with two things - one, we need to fix the foreach situation. Two, even before we find a fix, at this point committing to iteration with opApply essentially commits the iteratee to an island where all basic algorithms need to be reinvented from first principles.
Andrei
