[antlr-interest] The ^ and !

[Terence Parr]

Hmm...the ! on a root should be ok, right?  So, 2.7.2a2 doesn't like ! 
on the root?  what does it generate vs 2.7.1?

Ter

On Friday, September 20, 2002, at 02:30  PM, Alexander Lenski wrote:

> Thank you Terence for the answer.
> But what we got with the ! ?
> I have the AST transformation rules that are ok with the 2.7.1 but the 
> 2.7.2a2 generates err msgs as it is promised.
> Should I change the rules or wait for the final 2.7.2?
>  
> Typical rule:
>  
> protected
> me_to_s_literal[ MCall* pMC, TYPE_SP_T& spWS ]
> { assert( pMC );
>   TYPE_SP_AST spR;
> }
> : #( spO:PP_TO_S_LITERAL!
>        (   IDENT!
>            { Some code
>            }
>          | PP_VA_ARGS!
>            { Some code
>            }
>    )  )
>    { Some code
>    }
> ;
>  
> Thanks,
> Alexander Lenski
>  
> ----- Original Message -----
> From: "Terence Parr" <parrt at jguru.com>
> To: <antlr-interest at yahoogroups.com>
> Sent: Friday, September 20, 2002 2:42 PM
> Subject: Re: [antlr-interest] The ^ and !
>
> >
> > On Friday, September 20, 2002, at 10:59  AM, Alexander Lenski wrote:
> >
> > > From the CHANGES-2.7.2.txt:
> > >
> > > "Bad code gen with ^ or ! on tree root
> > > when building trees in a tree walker grammar such as:
> > >
> > > expr: #(PLUS^ expr expr)
> > > | i:INT
> > > ;
> > >
> > > Fortunately, ^ is simply redundant; removing it makes code ok.
> > > Added a warning. Added an error message for ! saying that it
> > > is not implemented."
> > >
> > > Are the ^ and ! not implemented yet or they are gone forever?
> >
> > Hi.  They are still there...just don't use ^ on the root...it's 
> already
> > a root.
> >
> > Ter
> > --
> > Co-founder, http://www.jguru.com
> > Creator, ANTLR Parser Generator: http://www.antlr.org
> >
> >
> >  
> >
> > Your use of Yahoo! Groups is subject to 
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> >
> >
> >
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Creator, ANTLR Parser Generator: http://www.antlr.org
Lecturer in Comp. Sci., University of San Francisco


 

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