[Bug: 21.5-b21] Regexp Isearch does not work with '\t'

[David Kastrup]

"Stephen J. Turnbull" <stephen at xemacs.org> writes:

>>>>>> "Ernst" == Ernst Taumberger <e.taumberger at centersystems.at> writes:
>
>     Ernst> the command isearch-forward-regexp("a[\t]+b") fails; it
>     Ernst> works if I replace the escape sequence with the
>     Ernst> tab-character itself
>
> In general XEmacs doesn't support backslash escapes in minibuffer
> input, so that is the regexp "a" followed by one or more repetitions
> of the class containing "\" and "t" followed by "b".
>
> I think this is a feature.

I would not call it a feature.  It is a simple consequence of the fact
that \t is string syntax.  And actually,

     Ernst> the command isearch-forward-regexp("a[\t]+b") fails; it

is misleading, since with _that_ syntax, an actual TAB character is
implied.

There are some cases in interactive use of CVS Emacs where \n and \t
trigger a warning message.  At the current point of time this seems to
be restricted to the query-replace-regexp family, in the match string.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum