DMD 0.170 release (foreach_reverse)

[Marcin Kuszczak]

Completely agree with below !

vote++ to remove foreach_reverse

Marcin Kuszczak
Aarti_pl

------------------------

Bill Baxter wrote:

> Walter Bright wrote:
> 
>> The saving grace about foreach_reverse is:
>> 
>> 1) Only a small (5% ?) of loops will be reverse, so you won't see it or
>> need to type it that often.
> 
> A good reason why it doesn't deserve its own keyword.
> 
>> 2) It's very clear what it does.
> 
> And  'foreach(i; list.reversed)' is pretty clear as well.
> 
>> 3) It isn't likely to conflict with other names.
> 
> Because it's a 15 letter keyword with an underscore!  While we're at it,
> let's make a for_i_equals_one_to_ten keyword, too.  I loop from 1 to 10
> a lot in my code (well, not that much really <5%, but at least it's a
> name that's not likely to conflict with other names).
> 
>> 4) It is analogous with C++'s reverse_iterator names.
> 
> But those aren't keywords.  And even more analogous is STL's
> std::for_each in the standard header 'algorithm'.
>     http://www.sgi.com/tech/stl/for_each.html
> Note that STL does not have a std::for_each_reverse.  You get that
> behavior, as you might expect, by using a reverse iterator instead of a
> forward iterator as the argument.
> 
> 
> And in another message Walter Bright wrote:
> 
>  > foreach_reverse was pretty trivial to implement. All the machinery
> was > already there.
> 
> That should be setting off warning bells in your head, too.  "The
> machinery is already there" is just another way of saying "this feature
> is mostly redundant". The foreach machinery already does the job.
> foreach_reverse is more or less just a copy-paste of that code with all
> references to "opApply" replaced with "opApplyReverse".  So of course
> it's trivial to implement.
> 
> I'll repeat a line from the "zen of python" one more time, at the risk
> of being told that 'D isn't Python', because I think it's true
> regardless of the language:
> 
>    "Special cases aren't special enough to break the rules."
> 
> As I understand it, the only real reason for foreach_reverse, when it
> comes down to it, is because of a strong desire to have a special case
> fast reverse iteration for arrays and strings.  But it really should be
> possible to hide that special case from the user and just detect some
> particular property e.g. "some_array.reversed" in a foreach statement.
> It may be a little more work (and maybe you just punt on the
> optimization till 2.0), but in the long run, the language and all it's
> users will benefit from removing that special case.
> 
> --bb

-- 
Regards
Marcin Kuszczak
(Aarti_pl)