* bug#1939: suggestion: adding read-line function to elisp
@ 2009-01-17 18:13 xah lee
2009-01-18 5:48 ` Juanma Barranquero
[not found] ` <mailman.5150.1232258617.26697.bug-gnu-emacs@gnu.org>
0 siblings, 2 replies; 3+ messages in thread
From: xah lee @ 2009-01-17 18:13 UTC (permalink / raw)
To: bug-gnu-emacs
summary:
i'd like to have a read-line function in elisp, that will read a
given file and return a list of lines.
The reason is that in almost all modern scripting langs (php, perl,
python, ruby), there's such a function, so that users can get a list
of lines of a file in about single line of code. Getting lines as
list is a very frequent need.
elisp is very suitable for tasks of text processing. So, having such
a convenience function seems appropriate.
Here's a implementation:
(defun read-lines (file)
"Return a list of lines in FILE."
(with-temp-buffer
(insert-file-contents file)
(split-string
(buffer-substring-no-properties 1 (point-max)) "\n" t)
)
)
Thanks.
The thought came from a recent newsgroup discussion in comp.lang.lisp
http://groups.google.com/group/comp.lang.lisp/browse_frm/thread/
761fe827c8c9ea5e/
Here's a short article for some context:
• A Ruby Illustration of Lisp Problems
http://xahlee.org/UnixResource_dir/writ/lisp_problems_by_ruby.html
Xah
∑ http://xahlee.org/
☄
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#1939: suggestion: adding read-line function to elisp
2009-01-17 18:13 bug#1939: suggestion: adding read-line function to elisp xah lee
@ 2009-01-18 5:48 ` Juanma Barranquero
[not found] ` <mailman.5150.1232258617.26697.bug-gnu-emacs@gnu.org>
1 sibling, 0 replies; 3+ messages in thread
From: Juanma Barranquero @ 2009-01-18 5:48 UTC (permalink / raw)
To: xah lee; +Cc: 1939
On Sat, Jan 17, 2009 at 19:13, xah lee <xah@xahlee.org> wrote:
> Getting lines as list is a very frequent need.
>
> elisp is very suitable for tasks of text processing. So, having such a
> convenience function seems appropriate.
Getting lines as list is much less frequent in elisp. The reason is
that is much more flexible (and faster) to manipulate text in a buffer
than as a collection of strings.
So in most cases, using `with-temp-buffer' (as in your read-lines
function) is the Right Thing To Do.
Juanma
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: bug#1939: suggestion: adding read-line function to elisp
[not found] ` <mailman.5150.1232258617.26697.bug-gnu-emacs@gnu.org>
@ 2009-01-20 18:29 ` Ted Zlatanov
0 siblings, 0 replies; 3+ messages in thread
From: Ted Zlatanov @ 2009-01-20 18:29 UTC (permalink / raw)
To: bug-gnu-emacs
On Sun, 18 Jan 2009 06:48:10 +0100 Juanma Barranquero <lekktu@gmail.com> wrote:
JB> On Sat, Jan 17, 2009 at 19:13, xah lee <xah@xahlee.org> wrote:
>> Getting lines as list is a very frequent need.
>>
>> elisp is very suitable for tasks of text processing. So, having such a
>> convenience function seems appropriate.
JB> Getting lines as list is much less frequent in elisp. The reason is
JB> that is much more flexible (and faster) to manipulate text in a buffer
JB> than as a collection of strings.
JB> So in most cases, using `with-temp-buffer' (as in your read-lines
JB> function) is the Right Thing To Do.
OTOH, it would be nice to have a way to call a lambda for every line in
a file (`mapfile' essentially) without using a buffer. The function
would get the line and the line number as parameters. That would let
Emacs Lisp do some processing of large files without running out of
memory.
Ted
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-01-20 18:29 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-01-17 18:13 bug#1939: suggestion: adding read-line function to elisp xah lee
2009-01-18 5:48 ` Juanma Barranquero
[not found] ` <mailman.5150.1232258617.26697.bug-gnu-emacs@gnu.org>
2009-01-20 18:29 ` Ted Zlatanov
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