bug#13810: 24.3.50; Docstring of `newline' is confusing

[Xue Fuqiao]

On Mon, 25 Feb 2013 13:23:14 +0100
Stephen Berman <stephen.berman@gmx.net> wrote:

> On Mon, 25 Feb 2013 18:03:09 +0800 Xue Fuqiao <xfq.free@gmail.com> wrote:
> > In the doc string of the function `newline':
> >   Insert a newline, and move to left margin of the new line if it's
> >   blank.
> > To reproduce this bug:
> >
> >    emacs -Q
> >    M-<
> >    M-: (newline) RET
> > A new line appears, but the point doesn't move to left margin of the
> > first line.  
> I think you misread the doc string: point should -- and does -- move to
> the left margin of the *new* line.

You mean the *new* line is the second line (now)?

> Your report prompted me to check the code of newline and I think I found
> a bug: a comment says, "If the newline leaves the previous line blank,
> and we have a left margin, delete that from the blank line", but the
> code only checks whether the previous line consists of a *single* space
> or tab, so if there's more than one space or tab and the line is
> otherwise blank, these won't be deleted.

What does the "left margin" mean?  I'm a little confused here.  Does it mean 
the "margin" in the variable `left-margin-width'?

BTW there is another problem with the doc string of the function `newline'.  
The `auto-fill-function' in the doc string is somewhat ambiguous.  It is a Lisp 
function in simple.el, but it is also is a variable defined in buffer.c.

> Steve Berman

-- 
Best regards, Xue Fuqiao.
http://www.emacswiki.org/emacs/XueFuqiao