[antlr-interest] Antlr grammar for xml like grammar

Raphael Reitzig r_reitzi at cs.uni-kl.de
Mon Aug 25 01:02:59 PDT 2008


Hi!

Lexer rules are greedy and tried top-down. So, first ANTLR tries to  
match your input against TOK_TEXT. This works perfectly for ML  
comments as well, thus a token TOK_TEXT is created.

To get the behaviour you want, there are two possibilities:

1. change the order of your rules in such a way that they are  
occurring in an order of increasing generality.
2. use predicates. this can even be necessary if 1. fails, exspecially  
when there is no order as described.

There may be a solution including turning of greedy mode for some  
rules, but I have no experience with this.

Regards

Raphael

Ymo <ymo.mail at gmail.com> wrote (Mon Aug 25 05:50:08 2008):

> Hi.
>
> I am trying to write a lexer for an xml like grammar. I am pulling my hear
> for i don't understand why it is not working.
>
> The grammar goes like this :
>
> TOK_TEXT
> <% ... %>
> TOK_TEXT
> <%@ .... %>
> <%-- COMMENT --%>
>
>
> I can't  figure why my ml comments are getting eaten by the TOK_TEXT token
> always.
>
> YOur help is greatly appreciated !
>



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