[antlr-interest] Tree parser and Java interface question to passing rule results

[Thomas Bernhardt]

I found that in order for the "$constant.tree" to work, I have to turn on "output=AST" in my tree grammar. If I add "output=AST" then the generated tree walker doesn't compile: 

                adaptor.setTokenBoundaries(retval.tree, retval.start, retval.stop);

with "retval.stop" cannot be found as a symbol variable, since the result inherits from TreeRuleReturnScope and that doesn't have a member stop. There are other compiler errors.

Thanks,
Tom
----- Original Message ----
From: Terence Parr <parrt at cs.usfca.edu>
To: Thomas Bernhardt <bernhardttom at yahoo.com>
Cc: antlr-interest at antlr.org
Sent: Wednesday, January 2, 2008 5:43:49 PM
Subject: Re: [antlr-interest] Tree parser and Java interface question to passing rule results


Hi.
On Jan 2, 2008, at 12:39 PM, Thomas Bernhardt wrote:

Can someone please help me get a tree walker to invoke a Java method for a rule, passing the tree node representing the rule result?

I have the tree grammar as follows, and the "???" is what I'm trying to figure out:

valueExpr
    :     constant { leaveNode(???); }
    |      // ... 
    ;

constant
    :    INT_TYPE
    |    LONG_TYPE
    |    FLOAT_TYPE
    |    DOUBLE_TYPE
    |    STRING_TYPE
    |    BOOL_TYPE
    |    NULL_TYPE
    ;

The goal is to get the tree or node that resulted from the "constant" rule to be passed to the "leaveNode(Tree tree)" method. What should "???" be?







$constant.tree


Ter






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