"Invalid regular expression" in visual-basic-mode.el

"Invalid regular expression" in visual-basic-mode.el

[Mathias Dahl]

I am testing Emacs CVS on Windows XP (fetched from the
nqemacs-project) and get errors in visual-basic-mode that I
did not get in 21.3. I have turned on debug-on-error and the
problem is with the following code:

 (looking-at "^.*\\_[ 	]*$")

If you evaluate the above you will get the error mentioned
in the subject line.

Is this a bug in Emacs or in visual-basic-mode.el? I know a
bit of regexp myself and the example above seems valid to me.

/Mathias

Re: "Invalid regular expression" in visual-basic-mode.el

[Mathias Dahl]

Mathias Dahl <brakjoller@hotmail.com> writes:

> I am testing Emacs CVS on Windows XP (fetched from the
> nqemacs-project) and get errors in visual-basic-mode that I
> did not get in 21.3. I have turned on debug-on-error and the
> problem is with the following code:
> 
>  (looking-at "^.*\\_[ 	]*$")
> 
> If you evaluate the above you will get the error mentioned
> in the subject line.
> 
> Is this a bug in Emacs or in visual-basic-mode.el? I know a
> bit of regexp myself and the example above seems valid to me.

I solved my problem temporarily by changing the expression
to this:

(defconst visual-basic-continuation-regexp "^.*_[ \t]*$")

That extra backslash did not seem to make sense.

But still, is it really invalid?

/Mathias

Re: "Invalid regular expression" in visual-basic-mode.el

[Kevin Rodgers]

Mathias Dahl wrote:
 > Mathias Dahl <brakjoller@hotmail.com> writes:
 >>I am testing Emacs CVS on Windows XP (fetched from the
 >>nqemacs-project) and get errors in visual-basic-mode that I
 >>did not get in 21.3. I have turned on debug-on-error and the
 >>problem is with the following code:
 >>
 >> (looking-at "^.*\\_[ 	]*$")
 >>
 >>If you evaluate the above you will get the error mentioned
 >>in the subject line.
 >>
 >>Is this a bug in Emacs or in visual-basic-mode.el? I know a
 >>bit of regexp myself and the example above seems valid to me.
 >
 > I solved my problem temporarily by changing the expression
 > to this:
 >
 > (defconst visual-basic-continuation-regexp "^.*_[ \t]*$")
 >
 > That extra backslash did not seem to make sense.
 >
 > But still, is it really invalid?

\_ (backslash-underscore ) is not a defined regexp construct.  In the
past it was treated as a 2-character sequence; apparently now that
should be represented as "\\\\_".

-- 
Kevin Rodgers

Re: "Invalid regular expression" in visual-basic-mode.el

[Mathias Dahl]

Kevin Rodgers <ihs_4664@yahoo.com> writes:

>  > But still, is it really invalid?
> 
> \_ (backslash-underscore ) is not a defined regexp construct.  In the
> past it was treated as a 2-character sequence; apparently now that
> should be represented as "\\\\_".

So, is it a bug or a feature?

/Mathias