On 5/8/14, 1:41 PM, "Luís Marques" <l...@luismarques.eu>" wrote:
On Thursday, 8 May 2014 at 18:21:32 UTC, H. S. Teoh via
Digitalmars-d wrote:
I've thought about input ranges vs. output ranges for a bit. I think it
doesn't make sense for functions that process data to take an output
range: output ranges are data sinks, and should only be used for the
endpoint of a data processing pipeline. Since the string function
doesn't know whether or not it's the last in a pipeline (only the
calling code can know this), it should return an input range. If the
user code wants to put the result into an output range, then it should
simply use std.algorithm.copy.
I agree with H. S. Teoh. Indeed, I was thinking of trying to
create an alternative version of std.format which returned an
InputRange, instead of taking an OutputRange. The benefit of this
becomes obvious when you want to use std.format() in your own
ranges, which currently impairs laziness, pipelining, avoiding
memory allocations, etc.
Interesting. So then the range returned by format() will save everything
passed to it, which means...
int fun(int[] a)
{
auto before = format("Before: %s", a);
foreach (ref e; a) ++e;
auto after = format("After: %s", a);
writeln(before, "\n--->\n", after);
}
*ouch*
Andrei
