Wed Apr 29 11:42:49 CEST 2009

namespace mapping

I'd like to expand namespaces to something more abstract: a generic
identifier mapping mechanism.  This to implement the 'target: macro
which takes elements from a different namespace if they are not
transformer bindings.

The problem is that I can't seem to figure out how "local-expand" can
be used to turn the abstract mechanism back into a concrete identifier
mapping, so rpn-transformer instances can be looked up at compile
time through syntax bindings.

Now, to keep a bit of sanity, I found that staying away from deep
macro system internals is generally a good idea.  There's a reason why
these things are hidden: they are quite complicated.

So, I'm going to adopt the following convention:

  * At compile time (namespace ... id) is directly interpreted as (ns
    (namespace ...) id) and cannot be overridden.

  * For run time identifiers the frorm (namespace ... id) can have
    arbitrary meaning.

So later when I figure out how to properly implement this it could be