Re: Exposing Isearch toggleable options

[Juri Linkov]

>> I'm leaning more towards other suggested solutions anyway.
>
> Ok. Thanks everyone for the feedback. I've see 3 good suggestions here
> on this thread, all of which I like better than my current solution.
> What I list below are actually slightly modified versions in order to
> help expose this stuff.
>
> I'm ditching the two-line minibuffer I originally suggested. All of
> the options below keep the minibuffer as a single line.
> Listed in my order of preference.
>
> 1. On the right-edge of the minibuffer (if there's enough space),
> display “[C-h m] Mode help” (or, if we're fine with rebinding C-h here
> we can use just “[C-h] Help”). Hitting this key would the bring up
> `isearch-mode-help`.
>    This is probably the most consistent option, as plenty of other
> Emacs features offer a similar (C-h help) indicator.
>    If we go with this, I'll probably suggest some improvements to
> `isearch-mode-help`.

Instead of the Help buffer we could open a Customizable-like buffer
with widget-type fields, thus in addition to *showing* the current
search options and info about keys to change them, also allow
*changing* the current search options.

> 2. On the right-edge of the minibuffer (if there's enough space),
> display “[M-s] Options”. Hitting this key would then bring up a hydra
> with all defined options under M-s (preferably something dynamically
> generated, and not hardcoded, though this is just a detail).
>    This would be the prettiest option. Hydras also support delaying
> the display for a second or so, so people who know what they want
> wouldn't have to see it.

This will violate the layered architecture where specific packages
(that are sometimes fancy in the sense of not using traditional UI)
are built on top of the core packages like isearch.el (that of course
doesn't preclude from writing a isearch-hydra.el or hydra-isearch.el
combinations).

> 3. Display an information similar to the prompt I originally
> suggested, but on the mode-line.

We already have a precedent in C mode with mode-line like
“C/lah ,” (note the space character inside, indicating Word mode).
In Isearch doing the same will show something like “Isearch/c' w”
(case-sensitive char-folded lax-whitespace word search).

> In items 1 and 2, we could display the indicators on an idle timer if 
> preferred.
> Here's what the minibuffer might look like in that situation:
>
> Isearch: search string                            [C-h] Help

I doubt that users might want to see the same reminder “[C-h] Help”
permanently or when paused to look at the highlighted search results.