On 02/16/2011 05:24 PM, Steven Schveighoffer wrote:
On Wed, 16 Feb 2011 11:14:27 -0500, Andrej Mitrovic
<andrej.mitrov...@gmail.com> wrote:
On 2/16/11, spir <denis.s...@gmail.com> wrote:
for any reason, I would prefere
findBack(haystack, needle);
:-)
Or maybe find should have an extra parameter that decides if the
search begins from the beginning or the end of the range.
I just realized, this isn't possible in the general case. That is, given your
original range [5, 1, 2, 3, 4, 5, 1], the only way to get [5, 1] is to use
popFront.
Think about this. What are the basic operations of a bidirectional range?
popFront and popBack. There is no way to search from the back, and then use
that as the front end of the resulting range.
Essentially, the range API does not allow what you want unless you have a
random-access range, and I don't even know if that can be generalized. The
operation you are looking for is very different from what find does.
Agreed.
On the other hand, it is a basic operation very often provided by APIs for
collections --together with several other operations having a right- or -last
or version. And it's not like a trivial one-liner one would occasionnally
re-implement on occasion. This is ypically, I guess, the kind of service
std.algorithm is supposed to deliver. And we shouldn't find it elsewhere since
this module is precisely supposed to provide general purpose algorithms.
Thus, don't we face a contradiction, due to the fact that std.algorithm is
mainly range-oriented? How to reconciliate this with the broader "range" of
operations one would expect to find there?
In this case, couldn't we still have the extra parameter, and check the
collection allows random-access? Or have a variant with this extra param beeing
non-optional and a stricter template constraint allowing only random-access
ranges/collections?
Denis
--
_________________
vita es estrany
spir.wikidot.com
