RE: Looking for universal completion with simple UI

[Drew Adams <drew.adams@oracle.com>]

> I'm posting to ask about a completion model I have in mind. Before I
> code it up myself I'm trying to find any packages that already
> implement most or all of this functionality.
> 
> The Emacs Wiki Category page for Completion lists packages for
> minibuffer completion and text completion:
> http://www.emacswiki.org/emacs/CategoryCompletion
> 
> I want a package for completion both INSIDE and OUTSIDE of the
> minibuffer with a universal UI:
> - Minibuffer Input Completion:
>   - finding files
>   - switching buffers
>   - apropos for functions and variables
>   - and any other minibuffer history lists
> - Text Completion in a Buffer:
>   - code completion
>   - executables/commands at a comint prompt
>   - i-searching in the current buffer
>   - cycling through killed text for yanking
> 
> Further, I want to navigate via a couple "dimensions" of context,
> both historical (previous inputs I've entered), and alphabetical
> (previous and next alphabetically, as in files in a directory).
> 
> The UI model and keybindings for this might be as simple as:
> - show prefix candidates with TAB
> - show substring candidates with S-TAB
> - with candidates already shown, the second TAB/S-TAB would select
>   the first candidate
> - navigate candidates alphabetically with C-r, C-s
> - navigate candidates historically with C-p, C-n
> 
> Do any packages implement this already?

I think you will find that several packages support much or even
all of what you request.  Even vanilla Emacs supports much of it.

I can't speak for other packages (others will), but Icicles
supports pretty much all of what you mention.

Icicle features apply mainly to the minibuffer.

For in-buffer text (code) completion, whenever there are
multiple candidates matching the buffer text to be completed,
Icicles extends some vanilla commands to let you use its
minibuffer completion features (regexp or substring matching,
multiple-pattern matching, candidate sorting, cycling, etc.)

So for text completion, instead of cycling among multiple
candidates in place, Icicles uses the minibuffer and shows
the candidates in `*Completions*'.  When there is only one
candidate, text completion in Icicles reverts to vanilla,
in-place completion.

Apart from Emacs Lisp, Icicles offers nothing particular for
code completion that is language-specific.  But its completion
features are automatically available for any code-specific
completion that uses `completing-read'.

You can download Icicles from Emacs Wiki or MELPA, to try it.
http://www.emacswiki.org/Icicles