How to give an abbreviation to a namespace?

Question

I have a namespace hierarchy and want to give an abbreviations for some long namespace names. For example, I have

Math::Geometry::OneDimension::

and I want to use Ge for Geometry and D1 for OneDimension thus the following works

Math::Ge::OneDimension::
Math::Geoemtry::D1::
Math::Ge::D1::

Is it possible to use namespace alias to do it?

score 8 · Answer 1 · answered Dec 10 '13 at 15:07

8

You can use namespace aliases:

namespace D1 = Math::Geometry::OneDimension;

answered Dec 10 '13 at 15:07

Luchian Grigore

Shouldn't it be using XXX = ...? – the_drow Dec 10 '13 at 15:08
@the_drow: No, `using` simply brings the namespace in to scope. It doesn't create an alias for the namespace. – John Dibling Dec 10 '13 at 15:09
I'm sure I used the using XXX = YYY some time ago. – the_drow Dec 10 '13 at 15:10
1

@the_drow: That's C++11 syntax for a type alias, but can't be used for a namespace alias. – Mike Seymour Dec 10 '13 at 15:15
I haven't touched C++ for a very very long time. – the_drow Dec 10 '13 at 15:22

Mike Seymour · Accepted Answer · 2013-12-10T15:17:22.997

3

To access it like that, you'll need to declare namespace aliases inside their enclosing namespaces:

namespace Math {
   namespace Ge = Geometry;
   namespace Geometry {
       namespace D1 = OneDimension;
   }
}

You can, of course, declare the aliases in other scopes, and access them simply as Ge and D1 in that scope.

edited Dec 10 '13 at 15:17

answered Dec 10 '13 at 15:09

Mike Seymour

score 2 · Answer 3 · answered Dec 10 '13 at 15:08

2

namespace Ge = Math::Geonetry::OneDimension;

answered Dec 10 '13 at 15:08

John Dibling

score 1 · Answer 4 · answered Dec 10 '13 at 15:09

Either you can do the aliasing inside the namespace, or, you can do this, from the outside of the namespace :

namespace Ge = Math::Geometry;
namespace D1 = Ge::OneDimension;

Ge::element_of_geometry;
D1::element_of_one_dimension;

I prefer this solution but use it in a scope to avoid name clashing.

4 Answers4