[antlr-interest] (v3) Token aggregation

[Sean Walton]

With a grammar such as:

path
    : id+=IDENTIFIER ('.' id+=IDENTIFIER) -> ^(PATH $id+)
    ;

Are there option incompatibilities?  Currently, when I use the $id+ in 
the AST section, I get:

ANTLR Parser Generator   Early Access Version 3.0b3 (July 21, 2006)  
1989-2006
0:0: syntax error: assign.types: <AST>:141:55: unexpected AST node: idx
0:0: syntax error: assign.types: <AST>:0:0: expecting EOB, found 
'<end-of-alt>'
0:0: syntax error: assign.types: <AST>:0:0: unexpected end of subtree
0:0: syntax error: define: <AST>:141:55: unexpected AST node: idx
0:0: syntax error: define: <AST>:0:0: expecting EOB, found '<end-of-alt>'
0:0: syntax error: define: <AST>:0:0: unexpected end of subtree
0:0: syntax error: buildnfa: <AST>:141:55: unexpected AST node: idx
internal error: ANesC.g : java.lang.NullPointerException
org.antlr.tool.NFAFactory.build_AlternativeBlock(NFAFactory.java:373)
org.antlr.tool.TreeToNFAConverter.block(TreeToNFAConverter.java:779)
org.antlr.tool.TreeToNFAConverter.rule(TreeToNFAConverter.java:548)
org.antlr.tool.TreeToNFAConverter.rules(TreeToNFAConverter.java:374)
org.antlr.tool.TreeToNFAConverter.grammarSpec(TreeToNFAConverter.java:328)
org.antlr.tool.TreeToNFAConverter.grammar(TreeToNFAConverter.java:188)
org.antlr.tool.Grammar.createNFAs(Grammar.java:677)
org.antlr.tool.Grammar.checkAllRulesForLeftRecursion(Grammar.java:1288)
org.antlr.codegen.CodeGenerator.genRecognizer(CodeGenerator.java:276)
org.antlr.Tool.processGrammar(Tool.java:320)
org.antlr.Tool.process(Tool.java:251)
org.antlr.Tool.main(Tool.java:70)

When I use $id, it "works" (but I only get the first token in the 
loop).  The grammar I adopted has "memoize" and "backtrack".  Are these 
the problem?  Also, what does "memoize" mean (it's not defined in the WIKI)?

-Sean