srfi-26 (cut, cute)

srfi-26 (cut, cute)

[Daniel Skarda]

Hello,

  during summer I browsed through srfi specification and as an excercice I
implemented srfi-26 (curry-which-is-not-curry :-). I hope somebody with
write access to CVS will like it and commit it.

  I found cut and cute macros very handy (they usually safe you a lot of
boring typing and screen space :-) so maybe they should be also part of
ice-9/boot-9.scm.

Have a nice day,
0.

ps: The reference implementation uses define-syntax instead of define-macro.
I chose define-macro since I prefere this way of writing macros and
(use-modules (ice-9 syncase)) doubles guile startup time (at least on my comp).

;--- srfi/srfi-26.scm: ----------------------------------------------------------

(define-macro (cut slot . slots)
  (let loop ((slots	(cons slot slots))
	     (params	'())
	     (args	'()))
    (if (null? slots)
	`(lambda ,(reverse! params) ,(reverse! args))
      (let ((s	  (car slots))
	    (rest (cdr slots)))
	(case s
	  ((<>)
	   (let ((var (gensym)))
	     (loop rest (cons var params) (cons var args))))
	  ((<...>)
	   (if (pair? rest)
	       (error "<...> not on the end of cut expression"))
	   (let ((var (gensym)))
	     `(lambda ,(append! (reverse! params) var)
		(apply ,@(reverse! (cons var args))))))
	  (else
	   (loop rest params (cons s args))))))))

(define-macro (cute . slots)
  (let ((temp (map (lambda (s) (and (not (memq s '(<> <...>))) (gensym))) slots)))
    `(let ,(delq! #f (map (lambda (t s) (and t (list t s))) temp slots))
       (cut ,@(map (lambda (t s) (or t s)) temp slots)))))


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Re: srfi-26 (cut, cute)

[Neil Jerram]

>>>>> "Daniel" == Daniel Skarda <0rfelyus@ucw.cz> writes:

    Daniel> Hello, during summer I browsed through srfi specification
    Daniel> and as an excercice I implemented srfi-26
    Daniel> (curry-which-is-not-curry :-). I hope somebody with write
    Daniel> access to CVS will like it and commit it.

Looks good to me; I'll commit tomorrow unless anyone objects.  Have
you signed assignment and disclaimer papers to cover this?

        Neil



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Re: srfi-26 (cut, cute)

[Rob Browning]

Neil Jerram <neil@ossau.uklinux.net> writes:

> Looks good to me; I'll commit tomorrow unless anyone objects.  Have
> you signed assignment and disclaimer papers to cover this?

I'd suggest we not put it in ice-9 for now, though.  As a general
rule, I think we'd be better off moving in the direction of a smaller
base.

(ohh, and this reminds me -- we still need to fix gensym...)

-- 
Rob Browning
rlb @defaultvalue.org, @linuxdevel.com, and @debian.org
Previously @cs.utexas.edu
GPG=1C58 8B2C FB5E 3F64 EA5C  64AE 78FE E5FE F0CB A0AD


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