From: Pavol Droba (droba_at_[hidden])
Date: 2004-03-12 06:48:45
On Fri, Mar 12, 2004 at 11:55:22AM +0100, Toon Knapen wrote:
> First of all, the std::string of VisualAge is compatible with the
> standard (It seems like vacpp uses the Dinkum library BTW).
> So why algorithm/string/replace fails is a mystery to me. I tried to
> understand the code to see what't wrong but I don't really grasp the
> details of the implementation. For instance, where is
> 'has_native_replace_tester' defined ?
Testers are defined in spearate headers, in boost/algorithm/string/stl
directory. The reason for this it that there it a need to include the particular
stl header before tester. So if a user chooses not to include whole stl,
she can include only those testers that are needed.
Implementation is using testers as a workaround for compilers without
partial specialization. Current implementaion is no restrictive in any way,
therefore it is used as a default even form more compliant compilers.
This technique is called "Poor man's partial specialization"
> As a side remark, I wonder if declaring BOOST_STATIC_CONSTANT( bool, ...
> ) is legal C++. Paragraph 5.19.1 of the standard only talks about
> integral types and enums. However I did a small test like this
> Class A
> BOOST_STATIC_CONSTANT(bool, value = 3 ) ;
> } ;
> Int main()
> itn v = A::value ;
> std::cout << v << std::endl ;
> return ;
> And it compiles and gives the output '3' (although I would expect the
> boolean to int conversion to result in '1' instead of 3. But this is
> probably due to the 'enum-trick' in BOOST_STATIC_CONSTANT which might
> also be a cause for your test to fail.
Std 184.108.40.206 says, that bool is an integral type. But the problem can be
related to enum workaround. However, the examble you have provided seems ok.
Even if value==3, when used in a bool expression it should evaluate to "true".
And that is only thing I need.
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