Add tree heterogeneous lookup in alternative modes

[Jonathan Wakely]

On 05/06/15 23:00 +0200, François Dumont wrote:
>On 04/06/2015 14:41, Jonathan Wakely wrote:
>>On 03/06/15 21:56 +0200, François Dumont wrote:
>>>Hi
>>>
>>>   Here is a patch to add heterogeneous lookup to alternative 
>>>modes.
>>
>>Excellent.
>>
>>>To do so I had to expose __is_transparent as __has_is_transparent 
>>>to avoid confilct with existing __is_transparent.
>>
>>That's a better name, thanks.
>>
>>
>>>Should I put it in __detail namespace ?
>>
>>Could it just be protected instead of at namespace scope?
>
>No, debug containers are inheriting from normal containers, not from 
>_Rb_tree.

Ah yes, of course.

>>
>>If it can't be protected it's OK here you put it, it doesn't need to
>>be in __detail.
>>
>>But maybe we should rename the _Kt parameter of __hash_is_transparent
>>to _Unused, _Dummy or something like that. It only exists to make the
>>specialization dependent on a template argument of the functions that
>>use it.
>>
>
>I renamed it into _SfinaeType to make the purpose of this type clearer.
>
>>
>>>   * include/bits/stl_tree.h (_Rb_tree<>::__is_transparent<>): Move to
>>>   outer scope and rename in ...
>>
>>"rename to ..."
>not "rename into..." :-)

Nope :-)

>>>   (std::__hash_is_transparent<>): ... this.
>>
>>In <bits/stl_set.h> ...
>>
>>>@@ -429,12 +477,34 @@
>>>      std::pair<const_iterator,const_iterator>
>>>      equal_range(const key_type& __x) const
>>>      {
>>>-    std::pair<_Base_iterator, _Base_iterator> __res =
>>>+    std::pair<_Base_const_iterator, _Base_const_iterator> __res =
>>>    _Base::equal_range(__x);
>>>    return std::make_pair(const_iterator(__res.first, this),
>>>                  const_iterator(__res.second, this));
>>>      }
>>
>>Huh! Did calls to this function even compile before this fix?
>
>I had a closer look and yes, it was compiling because for set iterator 
>and const_iterator are just the same:

Ah, yes, of course (again).

>      // DR 103. set::iterator is required to be modifiable,
>      // but this allows modification of keys.
>      typedef typename _Rep_type::const_iterator iterator;
>      typedef typename _Rep_type::const_iterator const_iterator;
>
>However I slightly changed some tests to make sure the const version 
>of equal_range and some others are used.
>
>If it is still fine I will commit the attached patch tomorrow.

Yes, OK, thanks.