Re: skeleton.el _ versus @

[Stefan Monnier]

> It seems clear to me that the "backing-up" of _ with @ was an
> ill-conceived back-of-the-hand programming insertion to solve someone's
> region-mode problem.  It clearly was ill-thought out because it
> completely fails in normal insertion mode when you mix @ and _, as
> mmm-mode does.

Could ou give an real example where it "completely fails" ?
I understand that the behavior is different, but your previous
example is not very compelling since the difference is only
an "off by one" position.

> I can imagine that a solution is to have skeleton-insert examine the use
> made of @ and _ ex-post-facto.

No.  The two different situations can only be told apart by
asking the author.  In (nil "fun " str "(" @ ")" \n "{" \n _ "}"),
point should always end inside the parens.

> When you look at the design of skeleton-mode, _ is clearly the preferred
> way to set skeleton-point.  I really just cannot see how to justify
> completely abandoning the meaning of _ in any situation at all.  I can

_ indicates where to insert the region(s).

> perversion of the clear separation between _ and @.  My question is when
> was the _ @ distinction ruined by allowing @ to override the meaning of _.

In Emacs-21.1.

> Was it introduced by the original skeleton author, or was it
> inserted on-the-sly by someone else?

It was introduced by yours truly.  The reasoning behind it was
that editing generally takes place left-to-right, so point
should most naturally end up at the first interesting position.
Also it allowed to distinguish between where point should go
and where the region should go.


        Stefan