An idea for making define-macro more convenient to use

From: Sunnan (sunnan_at_handgranat.org)
Date: 02/25/05 

Date: Fri, 25 Feb 2005 00:20:48 GMT

How about making a version of define-macro (with another name) where
variables introdued are in their own separate namespace (for a broad
enough definition of the word "namespace"), and had to be explicitly
converted if we wanted to expose them?

E.g. in my-or (from _Teach Yourself Scheme_), "temp" would be in it's
own "macro-namespace" so that the following would be ok:

(define-macro* my-or
   (lambda (x y)
     `(let ((temp ,x))
        (if temp temp ,y))))

This could be a wrapper for using gensyms, so that it would expand to:

(define-macro my-or
   (lambda (x y)
     (let ((temp (gensym)))
       `(let ((,temp ,x))
          (if ,temp ,temp ,y)))))

If we wanted to deliberately introduce variables, we could wrap them in
a function to "convert" them from the "macro-namespace":
(define-macro* my-weird-or
   (lambda (x y)
     `(let (((capture temp) ,x))
         (if temp temp ,y))))

could expand to:
(define-macro my-weird-or
    (lambda (x y)
      `(let ((temp ,x))
          (if temp temp ,y))))