[antlr-interest] Changes in ASTFactory breaks custom AST classes

[Terence Parr]

On Sunday, December 8, 2002, at 05:44  AM, Marco Hunsicker wrote:

> Hi all,
>
> I've just updated to the current ANTLR distro (2.7.2a6-20021130) and
> noticed that my dereived ASTFactory did not work as expected anymore

Damn...

> (I only use the Java stuff). I took a look at antlr.ASTFactory.java
> and realized that the dup(AST) method changed (of course, the whole
> class was expanded, but this is the one change that has bitten me).
>
>
> 2.7.2a2 looked like
> <pre>
> public AST dup(AST t) {
>     return create(t); // if t==null, create returns null}
> }
> </pre>
>
>
> 2.7.2a6 does
> <pre>
> public AST dup(AST t) {
>     if ( t==null ) {
>         return null;
>     }
>     // don't just call
>     AST dup_t = create(t.getClass());
>     dup_t.initialize(t.getType(), t.getText());
>                   // ^
>                   // why not use initialize(t) ???
>     return dup_t;
> }
> </pre>

Ah!  Right...should be as you say...cut-n-paste + stupidity error ;)

> The problem (at least for me) lies in the fact that the duplicated
> node gets only initialized with the type and text! All other
> information stored in the original node is lost. I now simply
> override dup(AST) too, changing it back to the old behavior (I only
> use homogenous trees) but I'd rather expect dup(AST) to initialize the
> duplicated node via dup_t.initialize(t) or am I missing something here?

Nope...you're right.

> Another minor thing I've noticed is that the new "classHeaderPrefix"
> option (cool!) has been only implemented for lexers. I hope this is
> not intentional?

Ah.  Thanks...i'll fix.

> Anyway, many thanks for creating such an exceptional piece of
> software. Love it!

You are most welcome!

Ter
--
Co-founder, http://www.jguru.com
Creator, ANTLR Parser Generator: http://www.antlr.org
Lecturer in Comp. Sci., University of San Francisco


 

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