In order to debug a tree grammar the input must be an AST.
Presently the only way to gain access to AST input is through creating a parser that provides "remote debugging".
See How do I set up remote debugging anyway?.
It is necessary to first build an AST that will serve as input to the tree grammar parser.
This parser (sample.g) will not be a debug parser and must not be generated with the -debug option. Only the tree grammar (sampleWalker.g) source should be generated with the -debug option
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| title | sample.g | borderStyle | solid |
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grammar sample;
example : 'SOME TEXT TO PARSE';
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| title | sampleWalker.g | borderStyle | solid |
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tree grammar sampleWalker;
example : 'SOME TEXT TO PARSE';
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| title | remoteDebugDriver.java | borderStyle | solid |
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public class remoteAstDebugging
{
public static void main(String[] args) throws Exception {
CommonTokenStream tokens = new CommonTokenStream();
{
ANTLRInputStream input = new ANTLRInputStream( System.in );
sampleLexer lexer = new sampleLexer(input);
tokens.setTokenSource(lexer);
}
CommonTreeNodeStream nodes;
{
sampleParser parser = new sampleParser(tokens);
sampleParser.example_return example = parser.example();
CommonTree tree = (CommonTree)example.getTree();
nodes = new CommonTreeNodeStream(tree);
}
{
sampleWalker walker = new sampleWalker(nodes);
// remove these lines if not using templates
FileReader groupFileReader = new FileReader("cpp.stg");
StringTemplateGroup templates = new StringTemplateGroup( groupFileReader );
groupFileReader.close();
walker.setTemplateLib(templates);
sampleWalker.example_return example = walker.example();
System.out.println(example.toString());
}
System.exit(0);
}
}
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