Re: [eigen] Namespaces

[Andre Krause <post@xxxxxxxxxxxxxxxx>]

Benoît Jacob wrote:
> On Thursday 11 October 2007 11:46:54 Andre Krause wrote:
> > Cyrille Berger wrote:
> > > On Wednesday 10 October 2007, Benoît Jacob wrote:
> > > > we initially used namespaces, but switched to prefixing recently. The
> > > > reason is that namespace offer little protection as most users will want
> > > > to be "using namespace". For instance look at the EiObject class.
> > > > Without prefix, it'd be Object. A much too common name. If we
> > > > encapsulate it in a namespace, it becomes Eigen::Object, which is safe,
> > > > but... most users would like to "using namespace Eigen" and if some
> > > > class is called "Object" then "using namespace" is not an option,
> > > > because "Object" is a too polluting name.
> > > In that case the compiler would return an error, it's hardly a problem.
> > >
> > > > Look at what Qt does. Qt classes are not encapsulated in any namespace,
> > > > instead they have the Q prefix, like "QObject".
> > > Qt was first release at a time when namespaces were not well (if at all)
> > > supported by most C++ compiler.
> > why not make the eigen namespace name shorter?
> >
> > instead of Eigen::Vector<float,4>, just
> >
> > ei::Vector<float,4> ...
> >
> > it just looks better / more modern than EiVector...
> > and if it is that short, one is less tempted to use "using namespace".
> >
> > and finally, it is no problem to use some typedefs.
> >
> > so i personally would rather like to see the prefix "Ei" removed.. but
> > well, i could also easily life with the prefix. its just a bit uglier.
>
> It's really a matter of taste. Some people will prefer EiVector because it's 
> shorted. Some other people will prefer Ei::Vector because the :: is more 
> evocative. In any case, the namespacing is just a special kind of prefixing. 
> So here we're only discussing prefix aesthetics -- we could go on forever.
>
> And I'm not sure with what you mean with "it is no problem to use some 
> typedefs", but did you know, C++ doesn't allow cross-namespace typedefs. So
>
> namespace A { class B; }
> typedef A::B C;
>
> shouldn't compile.
oh - wasnt aware of this.

but after reading your other posts, i think you are right: it seems to be
just a matter of taste and makes absolutely no difference, if using namespaces
or prefixes.

keep on your great work!