Re: But then what are namespaces ?

[Gregory Heytings]

> > Elisp has a single namespace, and this does not change with shorthands.
>
> Many/most languages with namespaces map "local names" to a unique global 
> namespace (e.g using hierarchies like `org.gnu.foo.bar` to avoid 
> conflicts).

Yes, perhaps what I said wasn't clear enough: all languages have a single 
global namespace, and languages with namespaces have a single global 
namespace that is partitioned.  (I'm not sure what you mean by 
"many/most", I at least don't know languages with namespaces that use a 
different strategy.)

> So this new mechanism is not that different.

It depends how you define "different" ;-)  It is not entirely different 
indeed, from a user viewpoint it provides a similar feature, but it is 
different: in languages with namespaces, identifiers are bound in a 
certain subset of the global namespace, whereas this mechanism only allows 
you to locally expand an identifier prefix to another identifier prefix. 
It's more a preprocessor-like workaround, a poor man's implementation of 
namespaces if you want.