public Object visit(Identifier node, Object data) {
CflowExpressionContext ctx = (CflowExpressionContext)data;
String leafName = node.name;
Expression expression = ctx.getNamespace().getExpression(leafName);
if (expression != null) {
return new Boolean(expression.matchCflow(ctx.getClassNameMethodMetaDataTuples()));
}
else {
throw new RuntimeException("no such registered expression");
}
}