public static VarcharTypeInfo getVarcharTypeInfo(ASTNode node)
      throws SemanticException {
    if (node.getChildCount() != 1) {
      throw new SemanticException("Bad params for type varchar");
    }

    String lengthStr = node.getChild(0).getText();
    return TypeInfoFactory.getVarcharTypeInfo(Integer.parseInt(lengthStr));
  }
Performs a descent of the leftmost branch of a tree, stopping when either a
node with a non-null token is found or the leaf level is encountered.

@param tree
         candidate node from which to start searching

@return node at which descent stopped
ql/src/java/org/apache/hadoop/hive/ql/parse/ParseUtils.java