Re: [Boost-users] BOOST_FOREACH with Index

Subject: Re: [Boost-users] BOOST_FOREACH with Index
From: OvermindDL1 (overminddl1_at_[hidden])
Date: 2009-12-13 21:12:48

On Sun, Dec 13, 2009 at 7:11 PM, OvermindDL1 <overminddl1_at_[hidden]> wrote:
> On Sun, Dec 13, 2009 at 6:41 PM, Nat Goodspeed <nat_at_[hidden]> wrote:
>> Eric Niebler wrote:
>>
>>>>> Â  Â Why not:
>>>>>
>>>>> Â  Â  int index = 0;
>>>>>
>>>>> Â  Â  BOOST_FOREACH(const Foo &f, foos)
>>>>> Â  Â  {
>>>>> Â  Â  Â  // ... stuff ...
>>>>> Â  Â  Â  ++index;
>>>>> Â  Â  }
>>
>>> What value BOOST_FOREACH has comes primarily from its ability to simplify
>>> something that's already pretty darn simple -- a plain for(;;) loop. I
>>> strongly resist any effort to make BOOST_FOREACH more complicated, unless
>>> the wins are truly significant. In this case, I don't think they are.
>>
>> Maybe this shouldn't be a BOOST_FOREACH feature at all. As with Python's
>> builtin enumerate() function, maybe what we want here is an iterator adapter
>> that dereferences to a std::pair<index_type, original_iterator_value_type>?
>
> Ooo, that makes sense, as long as it can still be done quickly (ala
> the in index = 0; example above):
> BOOST_FOREACH(size_t i, const Foo &f, ENUMERATE(foos))
>
> Or maybe:
> BOOST_FOREACH_ENUMERATE(size_t i, const Foo &f, foos)
>

Er, meant my first example to be:
BOOST_FOREACH(tuple<size_t, const Foo&> t, ENUMERATE(foos))