Re: pretty-printing?

[David St-Hilaire <sthilaid at iro dot umontreal dot ca>]

Per Bothner wrote:
> David St-Hilaire wrote:
>> I'm completely new to kawa and I have a few questions.
> 
> Welcome!
> 
>> I wrote a simple macro which is:
>>
>> (define-macro (pp arg)
>>   `(begin (display ,arg) (newline)))
> 
> This is a FAQ (though alas Kawa doesn't have an FAQ list).
> Answer: Don't use define-macro or defmacro.
> Instead use define-syntax:
> 
> (define-syntax pp
>   (syntax-rules ()
>     ((pp arg) (begin (display arg) (newline)))))

Ok thanks! Since I mostly used gambit before, I'm more used to define-macro
style macros! Lets say, for example, that I want to have an ugly imperative
style 'for macro like:

(define-macro (for init limit . exps)

  (let ((var (gensym 'i))

        (loop (gensym 'loop)))

    `(let ,loop ((,var ,init))

          (if (< ,var ,limit)

              (begin ,@exps

                     (,loop (+ ,var 1)))))))

then, in the define-syntax style, would the macro:

(define-syntax for

  (syntax-rules ()

    ((_ init limit exp1 . exps)

     (let loop ((var init))

             (if (< var limit)

                 (begin (begin exp1 . exps)

                        (loop (+ var 1))))))))

be equivalent...? Sorry for theses newb questions, I just want to make sure that
I got it right! ^_^

Thank you and happy scheming! ^_^Y

David

Attachment: signature.asc
Description: OpenPGP digital signature