bug#52558: Option for easier typing of regexps

[Juri Linkov]

>>> Such option already exists, and it allows using custom regexp syntax
>>> both for isearch and query-replace:
>>
>> Interesting, though its help mentions only isearch, so if I start
>> M-x query-replace-regexp directly, it doesn't seem affected.
>
> It affects all commands started from isearch: isearch-query-replace,
> isearch-occur, isearch-highlight-regexp.

It occurred to me now that when isearch-mode is disabled,
these commands could call isearch-edit-string to read
a search string, then proceed with their usual flow.