[antlr-interest] Problem splicing island grammar subtree into main AST

[Mike J. Bell]

OK, I finally figured out what my problem was...I'm not splicing an island
grammar AST into the main AST properly.  Extrapolating from the island
grammar example, I made something like:


// note that a queue is required as there is delayed communication from
lexer to parser

SUBORDINATE
    :    '{'
    {
        SubordinateLexer l = new SubordinateLexer(input);
        CommonTokenStream cts = new CommonTokenStream(l);
        SubordinateParser p = new SubordinateParser(cts);
        SubordinateParser.root_return subordinate = p.root();
        subordinateQueue.queue((CommonTree) subordinate.tree);
    };

subordinatebody returns [CommonTree node]
    :    SUBORDINATE { $node = subordinateQueue.dequeue(); };

subordinate
    :    s=subordinatebody -> ^($s);


So the problem here is that I don't want to splice in $s...I want to splice
in $s.node, which is the valid returned subtree that I made in the lexer.
But that's not valid syntax.

Any ideas on how I can get what I want?  I thought about putting in a Java
code snippet that is mangled to get the $s.node manually, but I thought
that's a nasty solution that could break if ANTLR internals change in the
future.  Surely there must be some way I can express this tree splicing in
ANTLR directly?

Thanks again in advance for any ideas...

-- 
Mike J. Bell on gmail
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