Re: unifying emacs "go to definition" functionality

[Helmut Eller <eller.helmut@gmail.com>]

On Wed, Feb 20 2013, Brendan Miller wrote:

> 5. SLIME uses etags keybindings, but I don't think it uses etags stack.

SLIME does use the etags stack but with different keybindings.  We use
M-. to push and M-, to pop.  M-* is bound to the same command as M-, for
compatibility but most people prefer M-, because , and . are adjacent on
their keyboards and M-* is usually quite hard to type.

I think M-, is the better choice and it should be the standard.

[...]
> I'd be interested in taking a look at the implementation work behind
> this in the future, but initially I just wanted to put the idea out
> there for feedback.

Using the etags stack is pretty easy.  A more difficult problem is how
to deal with names that have multiple definitions or definitions that
have multiple source locations.  E.g. in Emacs Lisp a variable and a
function can have the same name or in C a function can have a prototype
definition in a .h file and the actual definition is a .c file.  This
problem is especially important with languages that have multiple
methods with the same name.

In SLIME, when a name has multiple definitions we display all
definitions (one per line with some context) in a special buffer and the
user must then choose which one he wants (the next/previous-line
commands in that buffer automatically displays the source of the current
definition in the other buffer).

The autocomplete package uses something like a menu for this problem.

etags jumps to the first candidate and provides something like
next/previous-definition commands, but I think that solution is very
hard to use.  At least it drives me nuts, because I never know how many
more definitions there are and I can't remember the key bindings.

Helmut