forward-sexp for strings

forward-sexp for strings

[Roland Winkler]

The function forward-sexp requires a buffer. Is there something
similar for parsing strings? Of course, I can always use
with-temp-buffer.

Roland

Re: forward-sexp for strings

[Pascal Bourguignon]

Roland Winkler <roland.winkler@physik.uni-erlangen.de> writes:

> The function forward-sexp requires a buffer. Is there something
> similar for parsing strings? Of course, I can always use
> with-temp-buffer.

(require 'cl)
(loop with s = "(sexp 1) (sexp 2) \"sexp 3\" sexp-4" 
      with e = 0
      for oe = (read-from-string s e)
      do (print (car oe))
      while (< (setf e (cdr oe)) (length s)))


(sexp 1)

(sexp 2)

"sexp 3"

sexp-4
nil

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
Until real software engineering is developed, the next best practice
is to develop with a dynamic system that has extreme late binding in
all aspects. The first system to really do this in an important way
is Lisp. -- Alan Kay

Re: forward-sexp for strings

[Roland Winkler]

Pascal Bourguignon <spam@mouse-potato.com> writes:
> Roland Winkler <roland.winkler@physik.uni-erlangen.de> writes:
>
>> The function forward-sexp requires a buffer. Is there something
>> similar for parsing strings? Of course, I can always use
>> with-temp-buffer.
>
> (require 'cl)
> (loop with s = "(sexp 1) (sexp 2) \"sexp 3\" sexp-4" 
>       with e = 0
>       for oe = (read-from-string s e)
>       do (print (car oe))
>       while (< (setf e (cdr oe)) (length s)))

Do I need here the (require 'cl)? It seems to me that
read-from-string is really the important thing in your example. And
if this function obeys the current syntax-table (the doc string
doesn't say anything about that) it should be exactly what I am
looking for.

Thanks!

Roland

Re: forward-sexp for strings

[Henrik Enberg]

> From: Roland Winkler <winkler@tfkp07.physik.uni-erlangen.de>
> Date: Thu, 10 Nov 2005 21:51:29 +0100

> Pascal Bourguignon <spam@mouse-potato.com> writes:
>> Roland Winkler <roland.winkler@physik.uni-erlangen.de> writes:
>>
>>> The function forward-sexp requires a buffer. Is there something
>>> similar for parsing strings? Of course, I can always use
>>> with-temp-buffer.
>>
>> (require 'cl)
>> (loop with s = "(sexp 1) (sexp 2) \"sexp 3\" sexp-4" 
>>       with e = 0
>>       for oe = (read-from-string s e)
>>       do (print (car oe))
>>       while (< (setf e (cdr oe)) (length s)))

> Do I need here the (require 'cl)? It seems to me that
> read-from-string is really the important thing in your example. And
> if this function obeys the current syntax-table (the doc string
> doesn't say anything about that) it should be exactly what I am
> looking for.

the `loop' macro is defined in cl.el, so you'll need it.  Personally,
I'd just use with-temp-buffer.  It's far more straightforward.

Re: forward-sexp for strings

[Roland Winkler]

Henrik Enberg <henrik.enberg@telia.com> writes:
>>> (require 'cl)
>>> (loop with s = "(sexp 1) (sexp 2) \"sexp 3\" sexp-4" 
>>>       with e = 0
>>>       for oe = (read-from-string s e)
>>>       do (print (car oe))
>>>       while (< (setf e (cdr oe)) (length s)))
>
>> Do I need here the (require 'cl)? It seems to me that
>> read-from-string is really the important thing in your example. And
>> if this function obeys the current syntax-table (the doc string
>> doesn't say anything about that) it should be exactly what I am
>> looking for.
>
> the `loop' macro is defined in cl.el, so you'll need it.  Personally,
> I'd just use with-temp-buffer.  It's far more straightforward.

If I strictly implement the above example, I'll need cl.el. But it
seems to me that `while' can do the job, too. (Haven't tried yet
what I want to do with this.)

Roland

Re: forward-sexp for strings

[Stefan Monnier]

>> The function forward-sexp requires a buffer. Is there something
>> similar for parsing strings? Of course, I can always use
>> with-temp-buffer.

Use a buffer.

>       for oe = (read-from-string s e)

read-from-string is indeed an alternative, but only to parse strings whose
content uses the elisp syntax.


        Stefan