[antlr-interest] adding actions to rules breaks stuff

[Mark Wright]

Hello Benjamin,

The ANTLR syntax:

import [Object s]

declares rule import as taking a parameter s.  So ANTLR is
pointing out that when you call it in document, it needs
to pass it the parameter, something like:

document [Object o]
     : (i+=import[o])* c+=thing* EOF {o=new Doc($i,o);}
    ;

If you wanted just a local variable instead, then these can
be declared like:

document
@init { Object o; }
    : i+=import* c+=thing* EOF {o=new Doc($i,o);}
    ;

import
@init { Object s; }
    : 'import' s_=Text eol_ {s=$s_;}
    ;

I strongly recommend buying and reading the ANTLR book.

Regards, Mark

On Mon, 11 Feb 2008 14:12:57 -0800
Benjamin Shropshire <shro8822 at vandals.uidaho.edu> wrote:

> I have a grammar that Antlr will process. However when I try to add
> actions
> 
> example:
> ///////
> document [Object o]
>     : i+=import* c+=thing* EOF {o=new Doc(i,o);}
>     ;
> 
> import [Object s]
>     : 'import' s_=Text eol_ {s=s_;}
>     ;
> //////
> it says this:
> 
>     missing parameter(s) on rule reference: import
> 
> When I add an action to the top most rule it works, but when I add an 
> action to any rule that is used by anyone else, I get that error
> message. I'm assuming I'm doing something wrong but I can't find
> anything in the docs that is useful. A (well documented) example or a
> pointer into the documentation would be appreciated. Also, how could
> I have found the info my self would be of even more help.
> 
> Benjamin Shropshire


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