Re: Default behaviour of RET.

[Alan Mackenzie <acm@muc.de>]

Hello, Stefan.

On Fri, Oct 18, 2013 at 03:52:22PM -0400, Stefan Monnier wrote:
> >> > The traditional docstring says that it moves to the left margin and
> >> > handles auto-filling.  Eli's suggestion of `(insert "\n")' doesn't do
> >> > that, and it's not what `newline' does when corrupted by
> >> > `electric-shock-mode'.  But I think it's useful behavior, and I think
> >> > programs should be able to rely on it (as opposed to users who can
> >> > modify the behavior of `One-Flew-Over-the-Cuckoos-Nest-mode' by
> >> > removing ?\n, or not invoke the mode in the first place).

> >> I can't remember ever seeing a piece of code which wants "the Emacs-23
> >> newline behavior".  Usually it either wants to (insert "\n") or it wants
> >> to simulate hitting RET.

> > I gave an example of such code in the post which opened this thread.  To
> > recap:

> > (newline)
> > (insert "(vi)")
> > (fill-paragraph)

> > The `-and-indent' behaviour messes up the indentation of "(vi)" and
> > causes it to get re-attached to the previous paragraph.

> I see why the above doesn't want the "simulate RET" behavior.
> But I don't see why it wouldn't work just fine with the (insert
> "\n") behavior?

The `newline' tidies up the previous paragraph, in particular it fills
it.  It might also cause abbreviations to be expanded.

I could easily adapt this piece of code to cope with the `-and-indent'
which has been attached to `newline', but that's not the point.

The point is that there are a near infinite number of invocations of
`newline' in the wild, and an unknown proportion of these, possibly
quite high, will depend on `newline' doing precisely what its doc string
says.  Their existence makes the utility of electric-indent-mode, at the
moment, questionable.

> >> This discussion would benefit from actual examples of code that
> >> fall into neither "do whatever RET does" nor "insert \n".

> > See above.  Any code which is interested in filling (or, possibly, even
> > margins, if anything actually uses these) will get broken by the
> > `-and-indent'.

> "any code which..." is not concrete.

I've given you a concrete example of such code, several times.  It's not
a particularly bizarre piece of code, either.

electric-indent-mode's indentation of a new line is broken.  Please take
this behaviour out.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).