bug#10705: 24.0.93; Collect strings matching regexp from Isearch

[Eli Zaretskii]

> From: Juri Linkov <juri@jurta.org>
> Date: Thu, 02 Feb 2012 23:02:03 +0200
> 
> Currently `isearch-occur' is not in sync with the interactive specification
> of `occur' that provides a new feature of `C-u M-x occur RET' that collects
> the matching strings into the `*Occur*' buffer without line numbers.
> 
> The following patch syncs code from `occur-read-primary-args' to 
> `isearch-occur'.

Btw, while at that, how about fixing the doc string as well.  What it
says now, viz.

>  Interactively, REGEXP is the current search regexp or a quoted search
>  string.  NLINES has the same meaning as in `occur'."

is not clear enough: what is a "quoted search string"?  I'd suggest to
describe explicitly the 3 cases handled by the code:

> +       (regexp (cond
> +                (isearch-word (word-search-regexp isearch-string))
> +                (isearch-regexp isearch-string)
> +                (t (regexp-quote isearch-string)))))

and refer to the relevant string in each case.