Re: SICP stream question

[Chris Baker]

Marius Vollmer <address@hidden> writes:

> Chris Baker <address@hidden> writes:
> 
> > I'm trying to implement streams (delayed lists) from SICP.  Here's
> > what I have so far:
> > 
> >     ;;; stream definitions
> >     (define cons-stream
> >       (procedure->macro
> >        (lambda (x env) `(cons ,(cadr x) (delay ,(caddr x))))))
> 
> Please use
> 
>     (define-macro (cons-stream a b)
>       `(cons ,a (delay ,b)))
> 
> or
> 
>     (defmacro cons-stream (a b)
>       `(cons ,a (delay ,b)))

Thanks!  Worked like a charm.

Is define-macro portable across the various scheme implementations?
The only thing I could find in r5rs was define-syntax, which I
couldn't get to work.

Thanks again,

cbb