Re: Logical Value Of A Pointer
On Feb 9, 4:37 am, blargg <blargg....@gishpuppy.com> wrote:
Jeff Schwab wrote:
James Kanze wrote:
I think that the widespread adoption STL iterator idiom makes
this even more important. I don't write:
if ( iter && iter->... )
That's an idiom I wish STL iterators supported. It would
allow the passing of a single iterator, rather than a pair
of iterators, to generic algorithms. Of course, raw
pointers would cease to be valid iterators, so I don't have
high hopes.
But then how would an algorithm pass off a subset of the range
to another function? It could use ranges, but then you'd need
two interfaces for each algorithm.
Define an iterator which represents a range.
In practice, about the only time I've found that I need to pass
sub-ranges is when parsing. In which case, I either have a
string (and could use indexes), or an istreambuf_iterator (and
have to copy anyway). In addition, when parsing, it's usually
better if iterators have reference semantics; when a function
consumes characters, you want them consumed in the calling
function as well. So I tend to use C++'s other iterator idiom
for this: std::streambuf. (Actually, I've since implemented my
own ParserSource hierarchy. On one hand, to avoid all the extra
baggage of buffer management when not needed, and on the other,
to provide for automatic copying when needed.)
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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