Re: special forms (save-excursion)

[Kalle Olavi Niemitalo <tosi at stekt dot oulu dot fi>]

Keisuke Nishida <kxn30@po.cwru.edu> writes:

> Kalle Olavi Niemitalo <tosi@ees2.oulu.fi> writes:
> 
> > Should I use defmacro instead of syntax-rules?  I like
> > syntax-rules more, but it seems slower.
> 
> I think faster one is better.  This is not a complex syntax and
> easy to maintain.

But the macros made with define-macro (what is the difference
between that and defmacro?) are not hygienic by default.  Should
we hygienize each of them separately, or do we just give people a
list of symbols which they must not rebind when using the macros?

> (define-public (lisp-false? sexp) (or (eq? sexp ()) (eq? sexp nil)))

R5RS doesn't say what () evaluates to, so it would be better to
quote it.

I believe "sexp" means the usual printed form of an expression.
The parameter of lisp-false? is the object itself, not a printed
form.  Use "obj" instead.

> (define-public (lisp-variable-set! symbol value)
>   (lisp-eval `(setq ,symbol ,value)))

The value should be quoted in the setq call.

(define-public (lisp-variable-set! symbol value)
  (lisp-eval `(setq ,symbol ',value)))

> (define-macro (import-lisp-variable-1 variable . rest)
>   (let ((name (if (pair? rest) (car rest) variable)))
>     `(define ,name (make-procedure-with-setter
> 		    (lambda () (lisp-variable-ref ',variable))
> 		    (lambda (value) (lisp-variable-set! ',variable value))))))
> (define-public import-lisp-variable import-lisp-variable-1)

Can't you just (export import-lisp-variable-1)?