[antlr-interest] Tree walking Q

[Gerald B. Rosenberg]

At 04:06 PM 6/4/2005, Terence Parr wrote:
>On Jun 4, 2005, at 3:37 PM, Gerald B. Rosenberg wrote:
>
>>Is there a default rule identifier?  Or, is there another mechanism
>>to enable the tree-parser to simply walk past those tokens not
>>otherwise identified to the parser?
>
>Hi.  In the lexer, we such a filtering mechanism, but there isn't
>such a beast for tree parsing unless than the brute force "find this
>subtree" kind of thing.

Looks like that is where I am headed.

>I suggest you look at JBurg, which is technically used for generating
>machine instructions but it does a great job of finding subtrees in a
>large tree.  You can even assign costs to each subtree match and it
>will find the best match.  Now that I say it, it is exactly what you
>want.  JBurg should merge nicely with ANTLR :)

Interesting, but I am just not sure it will meet my needs.  Looks like it 
would take quite a bit of work to coerce it into functioning as just a 
selective tree-walker.  BTW, it does have explicit ANTLR integration.

Rather than putting the work into generating my own dedicated  tree-walker 
or fudging around JBurg, is there any interest in my adding the feature to 
ANTLR?  Obviously not a widely needed feature, but it would make ANTLR just 
a bit more generalized.

Thanks again,
Gerald
----
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