RE: propose adding Icicles to Emacs

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

> I don't understand why it makes sense to do completion on regexps.
> Would you please explain?

This is, in my experience, the single most important (useful) feature that
Icicles has to offer. It is way out in front of any other Icicles feature or
combination of features in terms of its practical value. The benefits are
well documented in the doc I sent you (which is also on the wiki).

Two of the basic features of Icicles are (1) cycling among matching
candidates and (2) being able to match a regexp, not just a prefix. Icicles
started life with #1, but it wasn't until I added #2 that its utility took
off. #1 without #2 limits you, in effect, to working with smaller candidate
sets. Put conversely, you can make good use of even very large candidate
sets if you have regexp (or at least substring) matching. You can sort
candidates on the fly, to make cycling more efficient. You can narrow down
the set of candidates considerably, especially using multiple match patterns
("progressive completion").

My advice to new Icicles users is to not get in the bad habit of automatic,
"drone" cycling, but to instead take advantage of regexp (e.g. substring)
matching. Icicles is a different approach to completion, and regexp matching
is a large part of that. It doesn't sound like much, if you are not used to
it, and it can sound like something that would be overkill or would slow you
down, but I can honestly say that I use S-TAB (which is regexp completion)
much, much more than TAB, and I'm pretty sure that the same is true for
other Icicles users.

Please read the doc about this feature, and think about it. Here is a good
place to start:
http://www.emacswiki.org/cgi-bin/wiki/Icicles_-_Apropos_Completions.

But you will find that this feature (which I call "apropos completion") is
really at the heart of nearly every Icicles feature. That is, when you read
about the various features, their doc will nearly always make reference to
S-TAB, because each of the features is more useful when combined with regexp
matching.

Progressive completion (matching multiple patterns, taking the intersection
to narrow the candidate set) is a good example of a powerful feature that is
dependent on regexp, or at least substring, matching. Icicles search is
another. On-the-fly apropos (candidate help) is another. Really, there is
not a single Icicles feature I can think of that is not raised to a higher
level of utility by regexp matching.