[antlr-interest] Matching Substring In Lexer

Kunal Sawlani kunalsawlani at gmail.com
Mon Apr 26 16:02:42 PDT 2010


Hi,
Thanks to both of you, I have something which works now. However, I am
running into a slight issue, where the parser complaints that ANYTHING is
not defined, in case of the grammar Jim suggested, and for John's grammar,
it complaints that TEXTNODE is not defined. I tried defining these using
Fragment, but to no avail. Also, I am using a combined grammar, and will
splitting it into a lexer and parser be necessary?

Thanks for the help. Really appreciate it.

On Mon, Apr 26, 2010 at 5:02 PM, John B. Brodie <jbb at acm.org> wrote:

> Greetings!
>
> On Mon, 2010-04-26 at 16:40 -0400, Kunal Sawlani wrote:
> > Hi All,
> > I have been trying to solve a problem which I have been having in the
> lexer,
> > but with no luck. My example goes as follows.
> > I have a simple grammar with two tokens.
> > I want to treat the the string "$ text" as a token TEXTINPUT and
> everything
> > else as a token ANYTHING, which matches anything.
> > The scanning process works fine when you supply it the string "$ TEXT",
> the
> > correct token is returned. And if any other character is supplied, the
> token
> > ANYTHING is returned.
> > However, for the string "$1", the scanner complaints that it was looking
> for
> > ' ', and no viable alternative for 1. What I want it to return is two
> tokens
> > ANYTHING for the "$", and another token ANYTHING for "1". I was reading
> into
> > the concept of syntactic
> > predicates to solve this issue, but I am not quiet getting it right. If
> > anyone could point me in the right direction, it would be great. Also, I
> > wanted to know if there are any other approaches to solve this issue. I
> got
> > the syntactic predicates concept after reading the following article
> > http://www.jguru.com/faq/view.jsp?EID=459059
> >
> > <http://www.jguru.com/faq/view.jsp?EID=459059>Any help would be greatly
> > appreciated!
> > Thanks
> >
>
> see attached....
>
>
>
>


-- 
Kunal Sawlani


More information about the antlr-interest mailing list