On Wed, 22 Feb 2012 13:12:07 -0600, Jonathan M Davis <jmdavisp...@gmx.com>
wrote:
On Wednesday, February 22, 2012 12:16:43 Robert Jacques wrote:
There's a big difference between sealed and not accessible. .data's API
requires exposing an array, and there's no way to do this without
leaking
memory like a sieve in one way or another. However, if all you need is
to
iterate the contents, that's easy to do. I'm currently adding backwards
iteration. Even indexing is fairly efficient (not yet implemented),
particularly relative indexing (i.e. n from back or front).
I haven't seen too many use cases yet where accessing the underlying
array
is important, nor has it come up on bugzilla. I've found one case in
Phobos where appender was used as a stack. What's your example? What
features does it have to support and how efficient does it have to be?
It's can be useful to just get at the underlying array and pass it to
functions which are going to use it but not alter it (or at least not
append
to it). Iterating over it doesn't give you an array. And since appender's
entire purpose is simply to make appending to an array more efficient,
making it
impossible to treat it as one until you're done appending is overly
restrictive IMHO. Yes, if you leak references to the underlying data,
you're
asking for trouble, but that doesn't mean that it can't be used without
leaking memory.
Unfortunately, I don't have any code snippets with me at the moment, so I
can't give any concrete examples of usage, but any situation where you
want to
be able to operate on the array while building it needs the ability to
get at
the underlying array. Yes, in most cases, you're probably simply
appending to
the array, but at least once in a while, you need to operate on an array
while
building it.
- Jonathan M Davis
I view appender's purpose as array building, which is slightly different
from simply speeding up array appending. Simply put, an array is a
terrible data structure for building arrays. But, I can appreciate the
need for mutation and if a particular array building algorithm can't be
performed on appender, then appender has failed. Would exposing a
bidirectional array be sufficient for your usages? A random access range?
