* Iterating over all buffer lines
@ 2013-01-17 20:55 Sean McAfee
2013-01-18 2:15 ` Le Wang
0 siblings, 1 reply; 3+ messages in thread
From: Sean McAfee @ 2013-01-17 20:55 UTC (permalink / raw)
To: help-gnu-emacs
I have some code where I want to loop over all of the lines of text in a
buffer. I had a prior solution that involved repeatedly searching for
the regexp "^.+$", but that seemed a little heavyweight. Also, it only
found non-empty lines, and changing the "+" to a "*" to return all lines
causes an infinite loop.
I just tried my hand at writing a general iterate-all-lines construct,
and came up with this:
(loop for last-point = (point)
while (= 0 (forward-line))
for line = (buffer-substring-no-properties
last-point
(- (point) (if (bolp) 1 0)))
;; do something with line
)
Newlines are not returned, and as can be seen, I have to take care to
handle a final line that is missing a terminating newline.
Is there a better and/or more idiomatic way to go about it?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Iterating over all buffer lines
2013-01-17 20:55 Iterating over all buffer lines Sean McAfee
@ 2013-01-18 2:15 ` Le Wang
2013-01-18 2:43 ` Eric Abrahamsen
0 siblings, 1 reply; 3+ messages in thread
From: Le Wang @ 2013-01-18 2:15 UTC (permalink / raw)
To: Sean McAfee; +Cc: help-gnu-emacs
(while (not (= (point) (point-max)))
(message (buffer-substring-no-properties (point-at-bol) (point-at-eol)))
(forward-line 1))
On Fri, Jan 18, 2013 at 4:55 AM, Sean McAfee <eefacm@gmail.com> wrote:
> I have some code where I want to loop over all of the lines of text in a
> buffer. I had a prior solution that involved repeatedly searching for
> the regexp "^.+$", but that seemed a little heavyweight. Also, it only
> found non-empty lines, and changing the "+" to a "*" to return all lines
> causes an infinite loop.
>
> I just tried my hand at writing a general iterate-all-lines construct,
> and came up with this:
>
> (loop for last-point = (point)
> while (= 0 (forward-line))
> for line = (buffer-substring-no-properties
> last-point
> (- (point) (if (bolp) 1 0)))
> ;; do something with line
> )
>
> Newlines are not returned, and as can be seen, I have to take care to
> handle a final line that is missing a terminating newline.
>
> Is there a better and/or more idiomatic way to go about it?
--
Le
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Iterating over all buffer lines
2013-01-18 2:15 ` Le Wang
@ 2013-01-18 2:43 ` Eric Abrahamsen
0 siblings, 0 replies; 3+ messages in thread
From: Eric Abrahamsen @ 2013-01-18 2:43 UTC (permalink / raw)
To: help-gnu-emacs
Le Wang <l26wang@gmail.com> writes:
> (while (not (= (point) (point-max)))
> (message (buffer-substring-no-properties (point-at-bol) (point-at-eol)))
> (forward-line 1))
>
>
> On Fri, Jan 18, 2013 at 4:55 AM, Sean McAfee <eefacm@gmail.com> wrote:
>> I have some code where I want to loop over all of the lines of text in a
>> buffer. I had a prior solution that involved repeatedly searching for
>> the regexp "^.+$", but that seemed a little heavyweight. Also, it only
>> found non-empty lines, and changing the "+" to a "*" to return all lines
>> causes an infinite loop.
>>
>> I just tried my hand at writing a general iterate-all-lines construct,
>> and came up with this:
>>
>> (loop for last-point = (point)
>> while (= 0 (forward-line))
>> for line = (buffer-substring-no-properties
>> last-point
>> (- (point) (if (bolp) 1 0)))
>> ;; do something with line
>> )
Le Wang's solution is probably more idiomatic (for large-scale text
manipulation emacs seems better suited to working on a buffer than a
string), but you could also split the buffer substring on newlines and
map a function over the resulting list:
(mapcar (lambda (line)
(when line (manipulate-line line)))
(split-string
(buffer-substring-no-properties (point-min) (point-max)) "\n"))
^ permalink raw reply [flat|nested] 3+ messages in thread
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