[Chicken-users] Re: module for srfi-35

[F. Wittenberger]

Am Sonntag, den 12.10.2008, 22:55 +0200 schrieb felix winkelmann:
> On Fri, Oct 10, 2008 at 10:18 PM, Jörg F. Wittenberger
> <address@hidden> wrote:
> > I just noticed that my srfi-35 files does not do enough.
> >
> > At the end there is a:
> >
> > (import (rename srfi-35
> >                (condition? srfi35:condtition?)
> >                (message-condition? srfi35:message-condition?)
> >                (condition-message srfi35:condition-message)))
> > (set! condition? srfi35:condtition?)
> > (define message-condition? srfi35:message-condition?)
> > (define condition-message srfi35:condition-message)
> >
> > No, it's not.  message-condition? and condition-message I just added a
> > second ago.
> 
> Sorry, can't parse that.

My fault, indeed.

So, I have this srfi-35 module and want to access it's bindings from top
level and eval.

I figured that a somewhat typing-extensive way would be to import the
module into top level, renaming it's bindings and define top level
variables bound to the renamed imports.

The code snippet shows the example I used to try whether this works or
not.

This one did.

> >
> > Since there are a few more things to export according to the visible
> > pattern, I guess that's what (import (prefix ... is supposed to be used
> > for.  But when I tried, I ended up with unbound things again.

I would rather have used (import (prefix srfi-35 srfi35:)) .  But either
I did not understand what I should put where I left the ellipsis here or
this might not work correctly at top level?  Whatever I tried, the top
level bindings ended up as undefined values (or was it unbound?).

> >
> > Please: could I get an example here.
> >
> 
> No problem, just tell me what you want to do.

At best I would like to do:

(define foo '(import (prefix srfi-35 srfi:35)))

(define bar '(import (rename srfi-18 (raise issue))))

(define (export-them! lst envt)
 (fold-import-statements
  (lambda (param init) (apply environment-extend! init param) init)
  envt
  lst))

(define env (make-environment))

(export-them! foo env)
(export-them! bar env)

Now in "env" "issue" is bound to "raise", SRFI-35 is bound with prefix.

Desperately: get an example how to save some typing with rename.

Alternatively: get an idea how to save even more typing using low level
access.

/Jörg