private void buildSelectListEvaluators() throws SemanticException, HiveException
    {
      resultExprInfo = new ResultExprInfo();
      resultExprInfo.resultExprEvals = new ArrayList<ExprNodeEvaluator>();
      resultExprInfo.resultExprNames = new ArrayList<String>();
      resultExprInfo.resultExprNodes = new ArrayList<ExprNodeDesc>();
      //result
      ArrayList<ObjectInspector> selectListExprOIs = new ArrayList<ObjectInspector>();
      int i = 0;
      for(WindowExpressionSpec expr : selectSpec)
      {
        String selectColName = expr.getAlias();
        ASTNode selectColumnNode = expr.getExpression();
        ExprNodeDesc selectColumnExprNode =
            ResultExpressionParser.buildExprNode(selectColumnNode,
            selectListInputTypeCheckCtx);
        ExprNodeEvaluator selectColumnExprEval =
            ExprNodeEvaluatorFactory.get(selectColumnExprNode);
        ObjectInspector selectColumnOI = null;
        selectColumnOI = selectColumnExprEval.initialize(selectListInputOI);

        selectColName = getColumnName(selectColName, selectColumnExprNode, i);

        resultExprInfo.resultExprEvals.add(selectColumnExprEval);
        selectListExprOIs.add(selectColumnOI);
        resultExprInfo.resultExprNodes.add(selectColumnExprNode);
        resultExprInfo.resultExprNames.add(selectColName);
        i++;
      }

      resultExprInfo.resultOI = ObjectInspectorFactory.getStandardStructObjectInspector(
          resultExprInfo.resultExprNames, selectListExprOIs);
    }
<ul>
<li> check structure of Arguments:
<ol>
<li> First arg should be a String
<li> then there should be an even number of Arguments:
String, expression; expression should be Convertible to Boolean.
<li> finally there should be a String.
</ol>
<li> convert pattern into a NNode chain.
<li> convert symbol args into a Symbol Map.
<li> parse selectList into SelectList struct. The inputOI used to translate
these expressions should be based on the
columns in the Input, the 'path.attr'
</ul>
ql/src/java/org/apache/hadoop/hive/ql/udf/ptf/MatchPath.java