Re: bug#1939: suggestion: adding read-line function to elisp

[Ted Zlatanov <tzz@lifelogs.com>]

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