RE: Usability suggestion : completion for M-:

[Drew Adams]

> >> I think TAB should be bound to lisp-complete-symbol
> >> in M-x eval-expression, aka M-: .
>
> I think the only problem preventing this change is...
> When this is fixed, it makes sense to allow TAB to
> complete a lisp symbol...

Uh, why? What's wrong with M-TAB or ESC TAB for Lisp symbol completion,
exactly as in a Lisp buffer? If it's good enough for there, and it's always
been good enough for here (minibuffer) in the past, why change it? 

You complete a lot more symbols in a Lisp buffer than in the minibuffer with
M-:, and ESC TAB hasn't been a problem in a Lisp buffer, so far.

As I mentioned, I would rather see M-: take on _more_ of the character of
Emacs-Lisp mode, not less. If you want to spend energy improving M-:, then
let it act like a pop-up emacs-lisp-mode buffer, but with RET causing eval.
And let the value be pretty-printed. When that is realized, you will see the
utility of TAB to indent, just as in Emacs-Lisp mode.

There are several ways in which M-: might be improved, but I don't see
dedicating TAB to lisp-symbol completion to be one of them. That's a YAGNI,
IMO.

Just one opinion - I'm not crazy about this change, but I don't feel
strongly about it. It doesn't matter to me for my own use, because I use
Icicles anyway, but I think it's better for Emacs users to always think of
ESC TAB as the symbol-completion key. I don't see anything gained by this
change.

If you are looking for something for TAB to complete against in M-:, let it
be the items in `read-expression-history'. That, at least, is consistent
with other minibuffer completion: the entire minibuffer input is what is
completed, and then entered. Symbol completion is a different animal.