Re: [Chicken-users] [Q] How can I convert this lisp(SBCL) macro to chicken scheme?

[NeXT]

Thank you, what I miss from clojure is its uniform or homoiconic(?) style of sequence accessing; so one does not have to check current sequence is whether list or vector or others. I'd like to create macro or something for this. :-)

Sent from my iPhone

On Nov 7, 2014, at 5:16 PM, Martin DeMello <address@hidden> wrote:

check out the clojurian egg too: http://wiki.call-cc.org/eggref/4/clojurian

martin

On Thu, Nov 6, 2014 at 6:21 PM, Sungjin Chun <address@hidden> wrote:

Thank you. Though I'm not sure on my code is in good style, I managed to convert my

code to chicken scheme like this;

(set-read-syntax!
 #\[
 (lambda (port)
   (let loop ((c (peek-char port)) (exps '()))
     (cond ((eof-object? c)
            (error "EOF encountered while parsing [ ... ] clause"))
           ((char=? c #\])
            (read-char port) ; discard                                                                                                                                                                                              
            `(vector ,@(reverse exps)))
           ((char-whitespace? c)
            (read-char port) ; discard whitespaces                                                                                                                                                                                  
            (loop (peek-char port) exps))
           (else
            (let ((exp (read port)))
              (loop (peek-char port)
                    (cons exp exps))))))))

(print (with-input-from-string "[1 2 3 4 5]" read))

(set-read-syntax!
 #\{
 (lambda (port)
   (let loop ((c (peek-char port)) (exps '()))
     (cond ((eof-object? c)
            (error "EOF encountered while parsing [ ... ] clause"))
           ((char=? c #\})
            (read-char port) ; discard                                                                                                                                                                                              
            `(alist->hash-table (chop (list ,@(reverse exps)) 2)))
           ((char-whitespace? c)
            (read-char port) ; discard whitespaces                                                                                                                                                                                  
            (loop (peek-char port) exps))
           ((char=? c #\,)
            (read-char port) ; discard whitespaces                                                                                                                                                                                  
            (loop (peek-char port) exps))
           (else
            (let ((exp (read port)))
              (loop (peek-char port)
                    (cons exp exps))))))))

(print (with-input-from-string "{'a 10, 'b 20, 'c 30}" read))
(print (with-input-from-string "{'a 10 'b 20 'c 30}" read))

I post these code for people with similar needs like myself :-).

On Fri, Nov 7, 2014 at 10:33 AM, Evan Hanson <address@hidden> wrote:

Hi Sungjin,

These are typically referred to as "reader extensions" in the Scheme
world: http://api.call-cc.org/doc/library#sec:Reader_extensions

You'll probabably want `set-read-syntax!` in particular:
http://api.call-cc.org/doc/library/set-read-syntax!

Cheers,

Evan

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