bug#16546: C-s vs. whitespace highlighting

[Dani Moncayo <dmoncayo@gmail.com>]

>> When I specifically add two spaces to my search string, it usually means
>> that, at that point, I want at least two spaces. If I compare to the
>> similar feature of case folding, that one is deactivated when there is
>> an explicit capital letter in the search string. OTOH, the cases where I
>> actually want to match multiple spaces are rare enough.
>
> Yes, good idea.  I also think search for two whitespace chars in a row
> should temporary toggle `search-whitespace-regexp' to nil.

IMO, that behavior would make sense only when the whitespace chars are
entered interactively (i.e. typed on the keyboard), because if the
search string comes from another place (copy&paste, grabbed from the
buffer, ...), I don't think it would be a good idea to temporarily set
`search-whitespace-regexp' to nil.  And BTW, that reasoning applies
equally to case-fold-search.

IOW, if I copy some text "foo<any-whitespace>bar" from one place and
then go to Emacs and do "C-s C-y", I definitely want a "lax" search
wrt whitespace.

At least, that behavior should be configurable, IMO.

-- 
Dani Moncayo