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Re: [PATCH] add regexp-split
From: |
Nala Ginrut |
Subject: |
Re: [PATCH] add regexp-split |
Date: |
Fri, 01 Feb 2013 17:24:29 +0800 |
I found a bug in my previous regexp-split implementation, and fixed now:
-------------------------------------code---------------------------------
(define* (regexp-split regex str #:optional (flags 0))
(let ((ret (fold-matches
regex str (list '() 0 str)
(lambda (m prev)
(let* ((ll (car prev))
(start (cadr prev))
(tail (match:suffix m))
(end (match:start m))
(s (substring/shared str start end))
(groups (map (lambda (n) (match:substring m n))
(iota (1- (match:count m)) 1))))
(list `(,@ll ,s ,@groups) (match:end m) tail)))
flags)))
`(,@(car ret) ,(caddr ret))))
-------------------------------------end---------------------------------
Now it works fine like Python's regexp-split:
(regexp-split "([^ ]+) (.+)" "a b[^ _]")
==> ("" "a" "b[^ _]" "")
(regexp-split "([^0-9])([^+/*])" "123+456*/")
==> ("123" "+" "4" "56*/")
I discussed with Andy that regexp-split is a so very common thing that
we should add it into (ice-9 regex).
But considering there're three implementations so far, mine,cky's and
this:
http://lists.gnu.org/archive/html/guile-user/2011-03/msg00007.html
So...I'll left the decision for the maintainers. ;-)
The difference between them maybe: cky's is Perl style (plus Ruby/Java),
and mine is Python's (though I hate Python ;-P).
It's not important to any of them to be chosen, the real meaningful
thing is we do need regexp-split in Guile.
Regards.
Nala Ginrut <nalaginrut <at> gmail.com> writes:
>
>
> Now that we have previous thread on this topic, I think it's no need
to format a patch.
>
> Maybe this will solve the problem:
>
> (define* (regexp-split regex str #:optional (flags 0))
> (let ((ret (fold-matches
>
> regex str (list '() 0 str)
>
> (lambda (m prev)
>
> (let* ((ll (car prev))
>
> (start (cadr prev))
>
> (tail (match:suffix m))
>
> (end (match:start m))
>
> (s (substring/shared str start end))
>
> (groups (map (lambda (n) (match:substring m n))
>
> (iota (1- (match:count m))))))
>
> (list `(, <at> ll ,s , <at> groups) (match:end m) tail)))
>
> flags)))
> `(, <at> (car ret) ,(caddr ret))))
>
> On Fri, Dec 30, 2011 at 11:33 PM, Daniel Hartwig <mandyke <at>
gmail.com> wrote:
> On 30 December 2011 21:03, Neil Jerram <neil <at> ossau.homelinux.net>
wrote:
>
> > Nala Ginrut <nalaginrut <at> gmail.com> writes:
> >
> >> hi guilers!
> >> It seems like there's no "regexp-split" procedure in Guile.
> >> What we have is "string-split" which accepted Char only.
> >> So I wrote one for myself.
> >
> > We've had this topic before, and it only needs a search for
> > "regex-split guile" to find it:
> > http://old.nabble.com/regex-split-for-Guile-td31093245.html.
> >
> Good to see that there is continuing interest in this feature.
> IMO, the implementation here is more elegant and readable for it's use
> of `fold-matches'. The first implementation from the thread you
> mention effectively rolls it's own version of `fold-matches' over the
> result of `list-matches' (which is implemented using `fold-matches'
> !).
>
>
>
>
>
>
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