Re: [boost] [Review] ITL review starts today, February 18th

Subject: Re: [boost] [Review] ITL review starts today, February 18th
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-03-05 15:25:33

Joachim Faulhaber wrote:
> 2010/2/28 Barend Gehrels <barend_at_[hidden]>:
> >
> > and then gives the example " mySet.contains(42)". But
> > contains is NOT an method of std::set, but YES from
> > interval_set. This was confusing.
>
> my view on sets here is not governed by std::sets but rather by the
> mathematical notion of a set or the itl::Set concept that is part of
> my documentation. In this view the "is element of" function is pretty
> fundamental and it is available for itl::interval_set and for itl::set
> as bool T::contains(const domain_type&);
[snip]
> Which is the common interface, the fundamental aspect, that
> constitutes this semantic kernel? Would that signature contain
> find(x)? Would it contain contains(x)? Would it provide iterators?
>
> boost::dynamic_bitset does not implement find, it does not implement
> iterators. Would we therefore say it is not a set? Its signature does
> not provide contains(x) but it contains test(x), which IMO should be
> called contains(x).

I'm speaking from partial ignorance, but...

Wouldn't it be better to use non-member functions for those operations expected of a set?  Then, boost::dynamic_bitset would satisfy itl::contains(bitset, x) because it could be implemented in terms of test().  Likewise, std::set would satisfy because itl::contains(s, x) could be implemented in terms of find().

Using that approach, your concepts would apply to any type for which a specified set of non-member functions can be applied while meeting specific semantic requirements.  I should think many more types could be adapted to ITL without needing specific support form ITL with that approach.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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