Re: Searching for line beginning

[Lars Ingebrigtsen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> How 'bout adding an optional argument?

That's also an option, but there's already an optional parameter here,
so we'd end up with

  (buffer-substring (line-beginning-position nil t) (line-end-position nil t))

etc all over the place, which is a mouthful to both type and read.

I've done some grepping and reading code in the Emacs code base to
broadly guesstimate how much code means "give me a line" when they say
"give me a line" (as opposed to a field), and I think it's basically
most.  So I think just adding a new function name for the behaviour most
code is looking for would be a better long time solution.

I was also wondering how much the optional N argument is used (because I
wondered whether the new function should perhaps be N-less, because the
N value isn't intuitive -- -1 and 1 aren't symmetric), and it's a lot
more than I would have guessed -- about a third of the calls have a
non-nil/non-1 N.  Like:

          ;; Insert the entries just found.
          (while (= (line-beginning-position 0) (1- (point)))
            (backward-char))

and

              (insert "\n")
              (put-text-property
               (line-beginning-position 0) (line-beginning-position)
               'mpc-file (mpc-songs-hashcons (cdr (assq 'file song))))

and

    (narrow-to-region (line-beginning-position)
                      (line-beginning-position 2))

Now, some of these are just bad code (or were written before
`propertize' existed), but the N will stay in the new function (if
added).