http://git-wip-us.apache.org/repos/asf/incubator-systemml/blob/c04fc99f/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidator.java
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diff --git 
a/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidator.java 
b/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidator.java
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--- /dev/null
+++ b/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidator.java
@@ -0,0 +1,2040 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.sysml.parser.pydml;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.antlr.v4.runtime.ParserRuleContext;
+import org.antlr.v4.runtime.Token;
+import org.antlr.v4.runtime.tree.ErrorNode;
+import org.antlr.v4.runtime.tree.TerminalNode;
+import org.apache.commons.lang.StringUtils;
+import org.apache.sysml.parser.AssignmentStatement;
+import org.apache.sysml.parser.BinaryExpression;
+import org.apache.sysml.parser.BooleanExpression;
+import org.apache.sysml.parser.BooleanIdentifier;
+import org.apache.sysml.parser.BuiltinFunctionExpression;
+import org.apache.sysml.parser.ConditionalPredicate;
+import org.apache.sysml.parser.ConstIdentifier;
+import org.apache.sysml.parser.DMLProgram;
+import org.apache.sysml.parser.DataExpression;
+import org.apache.sysml.parser.DataIdentifier;
+import org.apache.sysml.parser.DoubleIdentifier;
+import org.apache.sysml.parser.Expression;
+import org.apache.sysml.parser.Expression.DataOp;
+import org.apache.sysml.parser.Expression.DataType;
+import org.apache.sysml.parser.Expression.ValueType;
+import org.apache.sysml.parser.pydml.PydmlParser.AddSubExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.AssignmentStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.AtomicExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.BooleanAndExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.BooleanNotExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.BooleanOrExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.BuiltinFunctionExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.CommandlineParamExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.CommandlinePositionExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.ConstDoubleIdExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ConstFalseExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ConstIntIdExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.ConstStringIdExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ConstTrueExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.DataIdExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.DataIdentifierContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.ExternalFunctionDefExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ForStatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.FunctionCallAssignmentStatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.FunctionCallMultiAssignmentStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.FunctionStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.IfStatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.IfdefAssignmentStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.IgnoreNewLineContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ImportStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.IndexedExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.InternalFunctionDefExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.IterablePredicateColonExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.IterablePredicateSeqExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.MatrixDataTypeCheckContext;
+import org.apache.sysml.parser.pydml.PydmlParser.Ml_typeContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ModIntDivExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.MultDivExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ParForStatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.ParameterizedExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.PathStatementContext;
+import org.apache.sysml.parser.pydml.PydmlParser.PmlprogramContext;
+import org.apache.sysml.parser.pydml.PydmlParser.PowerExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.RelationalExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.SimpleDataIdentifierExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.StatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.StrictParameterizedExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.StrictParameterizedKeyValueStringContext;
+import org.apache.sysml.parser.pydml.PydmlParser.TypedArgNoAssignContext;
+import org.apache.sysml.parser.pydml.PydmlParser.UnaryExpressionContext;
+import org.apache.sysml.parser.pydml.PydmlParser.ValueDataTypeCheckContext;
+import org.apache.sysml.parser.pydml.PydmlParser.WhileStatementContext;
+import org.apache.sysml.parser.AParserWrapper;
+import org.apache.sysml.parser.ExternalFunctionStatement;
+import org.apache.sysml.parser.ForStatement;
+import org.apache.sysml.parser.FunctionCallIdentifier;
+import org.apache.sysml.parser.FunctionStatement;
+import org.apache.sysml.parser.IfStatement;
+import org.apache.sysml.parser.ImportStatement;
+import org.apache.sysml.parser.IndexedIdentifier;
+import org.apache.sysml.parser.IntIdentifier;
+import org.apache.sysml.parser.IterablePredicate;
+import org.apache.sysml.parser.LanguageException;
+import org.apache.sysml.parser.MultiAssignmentStatement;
+import org.apache.sysml.parser.OutputStatement;
+import org.apache.sysml.parser.ParForStatement;
+import org.apache.sysml.parser.ParameterExpression;
+import org.apache.sysml.parser.ParameterizedBuiltinFunctionExpression;
+import org.apache.sysml.parser.ParseException;
+import org.apache.sysml.parser.PathStatement;
+import org.apache.sysml.parser.PrintStatement;
+import org.apache.sysml.parser.RelationalExpression;
+import org.apache.sysml.parser.Statement;
+import org.apache.sysml.parser.StatementBlock;
+import org.apache.sysml.parser.StringIdentifier;
+import org.apache.sysml.parser.WhileStatement;
+
+/**
+ * TODO: Refactor duplicated parser code dml/pydml (entire package).
+ *
+ */
+public class PydmlSyntacticValidator implements PydmlListener
+{      
+       private PydmlSyntacticValidatorHelper helper = null;
+       
+       private String _workingDir = ".";   //current working directory
+       private String _currentPath = null; //current file path
+       private HashMap<String,String> argVals = null;
+       
+       public PydmlSyntacticValidator(PydmlSyntacticValidatorHelper helper, 
String currentPath, HashMap<String,String> argVals) {
+               this.helper = helper;
+               this.argVals = argVals;
+               
+               _currentPath = currentPath;
+       }
+       
+       // Functions we have to implement but don't really need it
+       @Override
+       public void enterAddSubExpression(AddSubExpressionContext ctx) { }
+       @Override
+       public void enterAssignmentStatement(AssignmentStatementContext ctx) {}
+       @Override
+       public void enterAtomicExpression(AtomicExpressionContext ctx) { }
+       @Override
+       public void enterBooleanAndExpression(BooleanAndExpressionContext ctx) 
{ }
+       @Override
+       public void enterBooleanNotExpression(BooleanNotExpressionContext ctx) 
{ }
+       @Override
+       public void enterBooleanOrExpression(BooleanOrExpressionContext ctx) { }
+       @Override
+       public void 
enterCommandlineParamExpression(CommandlineParamExpressionContext ctx) { }
+       @Override
+       public void 
enterCommandlinePositionExpression(CommandlinePositionExpressionContext ctx) { 
}    
+       @Override
+       public void enterConstDoubleIdExpression(ConstDoubleIdExpressionContext 
ctx) { }
+       @Override
+       public void enterConstIntIdExpression(ConstIntIdExpressionContext ctx) 
{ }
+       @Override
+       public void enterConstStringIdExpression(ConstStringIdExpressionContext 
ctx) { }
+       @Override
+       public void enterDataIdExpression(DataIdExpressionContext ctx) { }
+
+       @Override
+       public void enterIgnoreNewLine(IgnoreNewLineContext ctx) { }
+       @Override
+       public void enterPmlprogram(PmlprogramContext ctx) { }
+       @Override
+       public void exitPmlprogram(PmlprogramContext ctx) { }
+       
+       @Override
+       public void enterEveryRule(ParserRuleContext arg0) {
+               if(arg0 instanceof StatementContext) {
+                       if(((StatementContext) arg0).info == null) {
+                               ((StatementContext) arg0).info = new 
StatementInfo();
+                       }
+               }
+               if(arg0 instanceof FunctionStatementContext) {
+                       if(((FunctionStatementContext) arg0).info == null) {
+                               ((FunctionStatementContext) arg0).info = new 
StatementInfo();
+                       }
+               }
+               if(arg0 instanceof ExpressionContext) {
+                       if(((ExpressionContext) arg0).info == null) {
+                               ((ExpressionContext) arg0).info = new 
ExpressionInfo();
+                       }
+               }
+               if(arg0 instanceof DataIdentifierContext) {
+                       if(((DataIdentifierContext) arg0).dataInfo == null) {
+                               ((DataIdentifierContext) arg0).dataInfo = new 
ExpressionInfo();
+                       }
+               }
+       }
+       @Override
+       public void 
enterExternalFunctionDefExpression(ExternalFunctionDefExpressionContext ctx) { }
+       @Override
+       public void enterForStatement(ForStatementContext ctx) {}
+       @Override
+       public void 
enterFunctionCallAssignmentStatement(FunctionCallAssignmentStatementContext 
ctx) { }
+       @Override
+       public void 
enterFunctionCallMultiAssignmentStatement(FunctionCallMultiAssignmentStatementContext
 ctx) { }
+       @Override
+       public void enterIfStatement(IfStatementContext ctx) { }
+       @Override
+       public void enterImportStatement(ImportStatementContext ctx) { }
+       @Override
+       public void enterIndexedExpression(IndexedExpressionContext ctx) { }
+       @Override
+       public void 
enterInternalFunctionDefExpression(InternalFunctionDefExpressionContext ctx) { }
+       @Override
+       public void enterMl_type(Ml_typeContext ctx) { }
+       @Override
+       public void enterModIntDivExpression(ModIntDivExpressionContext ctx) { }
+       @Override
+       public void enterMultDivExpression(MultDivExpressionContext ctx) { }
+       @Override
+       public void enterParameterizedExpression(ParameterizedExpressionContext 
ctx) { }
+       @Override
+       public void enterParForStatement(ParForStatementContext ctx) { }
+       @Override
+       public void enterPathStatement(PathStatementContext ctx) { }
+       @Override
+       public void enterPowerExpression(PowerExpressionContext ctx) { }
+       @Override
+       public void enterRelationalExpression(RelationalExpressionContext ctx) 
{ }
+       @Override
+       public void 
enterSimpleDataIdentifierExpression(SimpleDataIdentifierExpressionContext ctx) 
{ }
+       @Override
+       public void 
enterStrictParameterizedExpression(StrictParameterizedExpressionContext ctx) { }
+       @Override
+       public void enterTypedArgNoAssign(TypedArgNoAssignContext ctx) { }
+       @Override
+       public void enterUnaryExpression(UnaryExpressionContext ctx) { }
+       @Override
+       public void enterWhileStatement(WhileStatementContext ctx) { }
+       
+       @Override
+       public void visitErrorNode(ErrorNode arg0) { }
+       @Override
+       public void visitTerminal(TerminalNode arg0) { }
+       @Override
+       public void exitEveryRule(ParserRuleContext arg0) {}
+       // --------------------------------------------------------------------
+       private void setFileLineColumn(Expression expr, ParserRuleContext ctx) {
+               // expr.setFilename(helper.getCurrentFileName());
+               String txt = ctx.getText();
+               expr.setFilename(_currentPath);
+               expr.setBeginLine(ctx.start.getLine());
+               expr.setBeginColumn(ctx.start.getCharPositionInLine());
+               expr.setEndLine(ctx.stop.getLine());
+               expr.setEndColumn(ctx.stop.getCharPositionInLine());
+               if(expr.getBeginColumn() == expr.getEndColumn() && 
expr.getBeginLine() == expr.getEndLine() && txt.length() > 1) {
+                       expr.setEndColumn(expr.getBeginColumn() + txt.length() 
- 1);
+               }
+       }
+       
+       private void setFileLineColumn(Statement stmt, ParserRuleContext ctx) {
+               String txt = ctx.getText();
+               stmt.setFilename(helper.getCurrentFileName());
+               stmt.setBeginLine(ctx.start.getLine());
+               stmt.setBeginColumn(ctx.start.getCharPositionInLine());
+               stmt.setEndLine(ctx.stop.getLine());
+               stmt.setEndColumn(ctx.stop.getCharPositionInLine());
+               if(stmt.getBeginColumn() == stmt.getEndColumn() && 
stmt.getBeginLine() == stmt.getEndLine() && txt.length() > 1) {
+                       stmt.setEndColumn(stmt.getBeginColumn() + txt.length() 
- 1);
+               }
+       }
+       
+       // For now do no type checking, let validation handle it.
+       // This way parser doesn't have to open metadata file
+       @Override
+       public void exitAddSubExpression(AddSubExpressionContext ctx) {
+               if(ctx.left.info.expr != null && ctx.right.info.expr != null) {
+                       // Addition and subtraction operator same as DML
+                       Expression.BinaryOp bop = 
Expression.getBinaryOp(ctx.op.getText());
+                       ctx.info.expr = new BinaryExpression(bop);
+                       
((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       
((BinaryExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       
+       
+       @Override
+       public void exitModIntDivExpression(ModIntDivExpressionContext ctx) {
+               if(ctx.left.info.expr != null && ctx.right.info.expr != null) {
+                       String dmlOperator = "";
+                       if(ctx.op.getText().compareTo("//") == 0) {
+                               dmlOperator = "%/%";
+                       }
+                       else if(ctx.op.getText().compareTo("%") == 0) {
+                               dmlOperator = "%%";
+                       }
+                       else {
+                               helper.notifyErrorListeners("Incorrect operator 
(expected // or %)", ctx.op);
+                               return;
+                       }
+                       Expression.BinaryOp bop = 
Expression.getBinaryOp(dmlOperator);
+                       ctx.info.expr = new BinaryExpression(bop);
+                       
((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       
((BinaryExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       @Override
+       public void exitUnaryExpression(UnaryExpressionContext ctx) {
+               if(ctx.left.info.expr != null) {
+                       String fileName = helper.getCurrentFileName();
+                       int line = ctx.start.getLine();
+                       int col = ctx.start.getCharPositionInLine();
+                       
+                       if(ctx.left.info.expr instanceof IntIdentifier) {
+                               if(ctx.op.getText().compareTo("-") == 0) {
+                                       ((IntIdentifier) 
ctx.left.info.expr).multiplyByMinusOne();
+                               }
+                               ctx.info.expr = ctx.left.info.expr;
+                       }
+                       else if(ctx.left.info.expr instanceof DoubleIdentifier) 
{
+                               if(ctx.op.getText().compareTo("-") == 0) {
+                                       ((DoubleIdentifier) 
ctx.left.info.expr).multiplyByMinusOne();
+                               }
+                               ctx.info.expr = ctx.left.info.expr;
+                       }
+                       else {
+                               Expression right = new IntIdentifier(1, 
fileName, line, col, line, col);
+                               if(ctx.op.getText().compareTo("-") == 0) {
+                                       right = new IntIdentifier(-1, fileName, 
line, col, line, col);
+                               }
+                               
+                               Expression.BinaryOp bop = 
Expression.getBinaryOp("*");
+                               ctx.info.expr = new BinaryExpression(bop);
+                               
((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                               
((BinaryExpression)ctx.info.expr).setRight(right);
+                       }
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       @Override
+       public void exitMultDivExpression(MultDivExpressionContext ctx) {
+               Expression.BinaryOp bop = 
Expression.getBinaryOp(ctx.op.getText());
+               ctx.info.expr = new BinaryExpression(bop);
+               ((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+               ((BinaryExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       @Override
+       public void exitPowerExpression(PowerExpressionContext ctx) {
+               String dmlOperator = "";
+               if(ctx.op.getText().compareTo("**") == 0) {
+                       dmlOperator = "^";
+               }
+               else {
+                       helper.notifyErrorListeners("Incorrect operator 
(expected **)", ctx.op);
+                       return;
+               }
+               
+               Expression.BinaryOp bop = Expression.getBinaryOp(dmlOperator);
+               ctx.info.expr = new BinaryExpression(bop);
+               ((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+               ((BinaryExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       // TODO: 
+//     @Override
+//     public void exitMatrixMulExpression(MatrixMulExpressionContext ctx) {
+//             Expression.BinaryOp bop = 
Expression.getBinaryOp(ctx.op.getText());
+//             ctx.info.expr = new BinaryExpression(bop);
+//             ((BinaryExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+//             ((BinaryExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+//             setFileLineColumn(ctx.info.expr, ctx);
+//     }
+
+       // --------------------------------------------------------------------
+
+       @Override
+       public void exitRelationalExpression(RelationalExpressionContext ctx) {
+               if(ctx.left.info.expr != null && ctx.right.info.expr != null) {
+                       Expression.RelationalOp rop = 
Expression.getRelationalOp(ctx.op.getText());
+                       ctx.info.expr = new RelationalExpression(rop);
+                       
((RelationalExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       
((RelationalExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       // --------------------------------------------------------------------
+       
+       @Override
+       public void exitBooleanAndExpression(BooleanAndExpressionContext ctx) {
+               if(ctx.left.info.expr != null && ctx.right.info.expr != null) {
+                       String dmlOperator = "";
+                       if(ctx.op.getText().compareTo("&") == 0 || 
ctx.op.getText().compareTo("and") == 0) {
+                               dmlOperator = "&";
+                       }
+                       else {
+                               helper.notifyErrorListeners("Incorrect operator 
(expected &)", ctx.op);
+                               return;
+                       }
+                       
+                       Expression.BooleanOp bop = 
Expression.getBooleanOp(dmlOperator);
+                       ctx.info.expr = new BooleanExpression(bop);
+                       
((BooleanExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       
((BooleanExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       @Override
+       public void exitBooleanOrExpression(BooleanOrExpressionContext ctx) {
+               if(ctx.left.info.expr != null && ctx.right.info.expr != null) {
+                       String dmlOperator = "";
+                       if(ctx.op.getText().compareTo("|") == 0 || 
ctx.op.getText().compareTo("or") == 0) {
+                               dmlOperator = "|";
+                       }
+                       else {
+                               helper.notifyErrorListeners("Incorrect operator 
(expected |)", ctx.op);
+                               return;
+                       }
+                       
+                       Expression.BooleanOp bop = 
Expression.getBooleanOp(dmlOperator);
+                       ctx.info.expr = new BooleanExpression(bop);
+                       
((BooleanExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       
((BooleanExpression)ctx.info.expr).setRight(ctx.right.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+
+       @Override
+       public void exitBooleanNotExpression(BooleanNotExpressionContext ctx) {
+               if(ctx.left.info.expr != null) {
+                       Expression.BooleanOp bop = 
Expression.getBooleanOp(ctx.op.getText());
+                       ctx.info.expr = new BooleanExpression(bop);
+                       
((BooleanExpression)ctx.info.expr).setLeft(ctx.left.info.expr);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+       }
+       
+       // --------------------------------------------------------------------
+       
+       @Override
+       public void exitAtomicExpression(AtomicExpressionContext ctx) {
+               ctx.info.expr = ctx.left.info.expr;
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       @Override
+       public void exitConstDoubleIdExpression(ConstDoubleIdExpressionContext 
ctx) {
+               try {
+                       double val = Double.parseDouble(ctx.getText());
+                       int linePosition = ctx.start.getLine();
+                       int charPosition = ctx.start.getCharPositionInLine();
+                       ctx.info.expr = new DoubleIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+               catch(Exception e) {
+                       helper.notifyErrorListeners("cannot parse the float 
value: \'" +  ctx.getText() + "\'", ctx.getStart());
+                       return;
+               }
+       }
+
+       @Override
+       public void exitConstIntIdExpression(ConstIntIdExpressionContext ctx) {
+               try {
+                       long val = Long.parseLong(ctx.getText());
+                       int linePosition = ctx.start.getLine();
+                       int charPosition = ctx.start.getCharPositionInLine();
+                       ctx.info.expr = new IntIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+                       setFileLineColumn(ctx.info.expr, ctx);
+               }
+               catch(Exception e) {
+                       helper.notifyErrorListeners("cannot parse the int 
value: \'" +  ctx.getText() + "\'", ctx.getStart());
+                       return;
+               }
+       }
+
+       @Override
+       public void exitConstStringIdExpression(ConstStringIdExpressionContext 
ctx) {
+               String val = "";
+               String text = ctx.getText();
+               if(     (text.startsWith("\"") && text.endsWith("\"")) ||
+                       (text.startsWith("\'") && text.endsWith("\'"))) {
+                       if(text.length() > 2) {
+                               val = text.substring(1, text.length()-1);
+                       }
+               }
+               else {
+                       helper.notifyErrorListeners("something wrong while 
parsing string ... strange", ctx.start);
+                       return;
+               }
+                       
+               int linePosition = ctx.start.getLine();
+               int charPosition = ctx.start.getCharPositionInLine();
+               ctx.info.expr = new StringIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       // --------------------------------------------------------------------
+       
+       @Override
+       public void exitDataIdExpression(DataIdExpressionContext ctx) {
+               ctx.info.expr = ctx.dataIdentifier().dataInfo.expr;
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               ctx.info.expr.setAllPositions(helper.getCurrentFileName(), 
line, col, line, col);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       @Override
+       public void 
exitSimpleDataIdentifierExpression(SimpleDataIdentifierExpressionContext ctx) {
+               // This is either a function, or variable with namespace
+               // By default, it assigns to a data type
+               ctx.dataInfo.expr = new DataIdentifier(ctx.getText());
+               setFileLineColumn(ctx.dataInfo.expr, ctx);
+       }
+       
+       
+       private Expression incrementByOne(Expression expr, ParserRuleContext 
ctx) {
+               // For maintaining semantic consistency, we have decided to 
keep 1-based indexing
+               // If in future, PyDML becomes more popular than DML, this can 
be switched.
+               return expr;
+       }
+       
+       @Override
+       public void exitIndexedExpression(IndexedExpressionContext ctx) {
+               ctx.dataInfo.expr = new IndexedIdentifier(ctx.name.getText(), 
false, false);
+               setFileLineColumn(ctx.dataInfo.expr, ctx);
+               try {
+                       ArrayList< ArrayList<Expression> > exprList = new 
ArrayList< ArrayList<Expression> >();
+                       
+                       ArrayList<Expression> rowIndices = new 
ArrayList<Expression>();
+                       ArrayList<Expression> colIndices = new 
ArrayList<Expression>();
+                       
+                       boolean isRowLower = (ctx.rowLower != null && 
!ctx.rowLower.isEmpty() && (ctx.rowLower.info.expr != null));
+                       boolean isRowUpper = (ctx.rowUpper != null && 
!ctx.rowUpper.isEmpty() && (ctx.rowUpper.info.expr != null));
+                       boolean isColLower = (ctx.colLower != null && 
!ctx.colLower.isEmpty() && (ctx.colLower.info.expr != null));
+                       boolean isColUpper = (ctx.colUpper != null && 
!ctx.colUpper.isEmpty() && (ctx.colUpper.info.expr != null));
+                       
+                       if(!isRowLower && !isRowUpper) {
+                               // both not set
+                               rowIndices.add(null); rowIndices.add(null);
+                       }
+                       else if(isRowLower && isRowUpper) {
+                               // both set
+                               
rowIndices.add(incrementByOne(ctx.rowLower.info.expr, ctx));
+                               rowIndices.add(ctx.rowUpper.info.expr);
+                       }
+                       else if(isRowLower && !isRowUpper) {
+                               // only row set
+                               
rowIndices.add(incrementByOne(ctx.rowLower.info.expr, ctx));
+                       }
+                       else {
+                               helper.notifyErrorListeners("incorrect index 
expression for row", ctx.start);
+                               return;
+                       }
+                       
+                       if(!isColLower && !isColUpper) {
+                               // both not set
+                               colIndices.add(null); colIndices.add(null);
+                       }
+                       else if(isColLower && isColUpper) {
+                               
colIndices.add(incrementByOne(ctx.colLower.info.expr, ctx));
+                               colIndices.add(ctx.colUpper.info.expr);
+                       }
+                       else if(isColLower && !isColUpper) {
+                               
colIndices.add(incrementByOne(ctx.colLower.info.expr, ctx));
+                       }
+                       else {
+                               helper.notifyErrorListeners("incorrect index 
expression for column", ctx.start);
+                               return;
+                       }
+                       exprList.add(rowIndices);
+                       exprList.add(colIndices);
+                       ((IndexedIdentifier) 
ctx.dataInfo.expr).setIndices(exprList);
+               }
+               catch(Exception e) {
+                       helper.notifyErrorListeners("cannot set the indices", 
ctx.start);
+                       return;
+               }
+       }
+       
+       private ConstIdentifier getConstIdFromString(String varValue, Token 
start) {
+               // Both varName and varValue are correct
+               int linePosition = start.getLine();
+               int charPosition = start.getCharPositionInLine();
+               try {
+                       long val = Long.parseLong(varValue);
+                       return new IntIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+               }
+               catch(Exception e) {
+                       try {
+                               double val = Double.parseDouble(varValue);
+                               return new DoubleIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+                       }
+                       catch(Exception e1) {
+                               try {
+                                       if(varValue.compareTo("True") == 0 || 
varValue.compareTo("False") == 0) {
+                                               boolean val = false;
+                                               if(varValue.compareTo("True") 
== 0) {
+                                                       val = true;
+                                               }
+                                               return new 
BooleanIdentifier(val, helper.getCurrentFileName(), linePosition, charPosition, 
linePosition, charPosition);
+                                       }
+                                       else {
+                                               String val = "";
+                                               String text = varValue;
+                                               if(     (text.startsWith("\"") 
&& text.endsWith("\"")) ||
+                                                       (text.startsWith("\'") 
&& text.endsWith("\'"))) {
+                                                       if(text.length() > 2) {
+                                                               val = 
text.substring(1, text.length()-1);
+                                                       }
+                                               }
+                                               else {
+                                                       // the commandline 
parameters can be passed without any quotes
+                                                       val = text;
+                                               }
+                                               return new 
StringIdentifier(val, helper.getCurrentFileName(), linePosition, charPosition, 
linePosition, charPosition);
+                                       }
+                               }
+                               catch(Exception e3) {
+                                       helper.notifyErrorListeners("unable to 
cast the commandline parameter into int/float/bool/str", start);
+                                       return null;
+                               }
+                       }
+               }                       
+       }
+       
+       private void fillExpressionInfoCommandLineParameters(String varName, 
ExpressionInfo dataInfo, Token start) {
+               
+               if(!varName.startsWith("$")) {
+                       helper.notifyErrorListeners("commandline param doesnot 
start with $ ... strange", start);
+                       return;
+               }
+               
+               String varValue = null;
+               for(Map.Entry<String, String> arg : this.argVals.entrySet()) {
+                       if(arg.getKey().trim().compareTo(varName) == 0) {
+                               if(varValue != null) {
+                                       helper.notifyErrorListeners("multiple 
values passed for the parameter " + varName + " via commandline", start);
+                                       return;
+                               }
+                               else {
+                                       varValue = arg.getValue().trim();
+                               }
+                       }
+               }
+               
+               if(varValue == null) {
+                       // helper.notifyErrorListeners("the parameter " + 
varName + " either needs to be passed through commandline or initialized to 
default value", start);
+                       return;
+               }
+               
+               // Command line param cannot be empty string
+               // If you want to pass space, please quote it
+               if(varValue.trim().compareTo("") == 0)
+                       return;
+               
+               dataInfo.expr = getConstIdFromString(varValue, start);
+       }
+       
+       @Override
+       public void 
exitCommandlineParamExpression(CommandlineParamExpressionContext ctx) {
+               handleCommandlineArgumentExpression(ctx);
+       }
+
+       @Override
+       public void 
exitCommandlinePositionExpression(CommandlinePositionExpressionContext ctx) {
+               handleCommandlineArgumentExpression(ctx);
+       }
+       
+       /**
+        * 
+        * @param ctx
+        */
+       private void handleCommandlineArgumentExpression(DataIdentifierContext 
ctx)
+       {
+               String varName = ctx.getText().trim();          
+               fillExpressionInfoCommandLineParameters(varName, ctx.dataInfo, 
ctx.start);
+               
+               if(ctx.dataInfo.expr == null) {
+                       if(!(ctx.parent instanceof 
IfdefAssignmentStatementContext)) {
+                               String msg = "The parameter " + varName + " 
either needs to be passed "
+                                               + "through commandline or 
initialized to default value.";
+                               if( AParserWrapper.IGNORE_UNSPECIFIED_ARGS ) {
+                                       ctx.dataInfo.expr = 
getConstIdFromString(" ", ctx.start);
+                                       helper.raiseWarning(msg, ctx.start);
+                               }
+                               else {
+                                       helper.notifyErrorListeners(msg, 
ctx.start);
+                               }
+                       }
+               }
+       }
+       
+       // --------------------------------------------------------------------
+       
+       @Override
+       public void exitImportStatement(ImportStatementContext ctx)
+       {
+               //prepare import filepath
+               String filePath = ctx.filePath.getText();
+               String namespace = DMLProgram.DEFAULT_NAMESPACE;
+               if(ctx.namespace != null && ctx.namespace.getText() != null && 
!ctx.namespace.getText().isEmpty()) { 
+                       namespace = ctx.namespace.getText();
+               }
+               if((filePath.startsWith("\"") && filePath.endsWith("\"")) || 
+                               filePath.startsWith("'") && 
filePath.endsWith("'")) {   
+                       filePath = filePath.substring(1, filePath.length()-1);
+               }
+               
+               //concatenate working directory to filepath
+               filePath = _workingDir + File.separator + filePath;
+               
+               DMLProgram prog = null;
+               try {
+                       prog = (new PyDMLParserWrapper()).doParse(filePath, 
null, argVals);
+               } catch (ParseException e) {
+                       helper.notifyErrorListeners("Exception found during 
importing a program from file " + filePath, ctx.start);
+                       return;
+               }
+        // Custom logic whether to proceed ahead or not. Better than the 
current exception handling mechanism
+               if(prog == null) {
+                       helper.notifyErrorListeners("One or more errors found 
during importing a program from file " + filePath, ctx.start);
+                       return;
+               }
+               else {
+                       ctx.info.namespaces = new HashMap<String, DMLProgram>();
+                       ctx.info.namespaces.put(namespace, prog);
+                       ctx.info.stmt = new ImportStatement();
+                       ((ImportStatement) 
ctx.info.stmt).setCompletePath(filePath);
+                       ((ImportStatement) 
ctx.info.stmt).setFilePath(ctx.filePath.getText());
+                       ((ImportStatement) 
ctx.info.stmt).setNamespace(namespace);
+               }
+       }
+       
+       @Override
+       public void exitAssignmentStatement(AssignmentStatementContext ctx) {
+               if(ctx.targetList == null || ctx.targetList.size() != 1) {
+                       helper.notifyErrorListeners("incorrect parsing for 
assignment", ctx.start);
+                       return;
+               }
+               String targetListText = ctx.targetList.get(0).getText(); 
+               if(targetListText.startsWith("$")) {
+                       helper.notifyErrorListeners("assignment of commandline 
parameters is not allowed. (Quickfix: try using someLocalVariable=ifdef(" + 
targetListText + ", default value))", ctx.start);
+                       return;
+               }
+               
+               DataIdentifier target = null; 
+               if(ctx.targetList.get(0).dataInfo.expr instanceof 
DataIdentifier) {
+                       target = (DataIdentifier) 
ctx.targetList.get(0).dataInfo.expr;
+                       Expression source = ctx.source.info.expr;
+                       
+                       int line = ctx.start.getLine();
+                       int col = ctx.start.getCharPositionInLine();
+                       try {
+                               ctx.info.stmt = new AssignmentStatement(target, 
source, line, col, line, col);
+                               setFileLineColumn(ctx.info.stmt, ctx);
+                       } catch (LanguageException e) {
+                               // TODO: extract more meaningful info from this 
exception.
+                               helper.notifyErrorListeners("invalid 
assignment", ctx.targetList.get(0).start);
+                               return;
+                       } 
+               }
+               else {
+                       helper.notifyErrorListeners("incorrect lvalue ... 
strange", ctx.targetList.get(0).start);
+                       return;
+               }
+               
+       }
+
+       
+       private void setAssignmentStatement(DataIdentifier target, Expression 
expression, StatementContext ctx) {
+               try {
+                       ctx.info.stmt = new AssignmentStatement(target, 
expression, ctx.start.getLine(), ctx.start.getCharPositionInLine(), 
ctx.start.getLine(), ctx.start.getCharPositionInLine());
+                       setFileLineColumn(ctx.info.stmt, ctx);
+               } catch (LanguageException e) {
+                       // TODO: extract more meaningful info from this 
exception.
+                       helper.notifyErrorListeners("invalid function call", 
ctx.start);
+                       return;
+               }
+       }
+       
+       private void setPrintStatement(FunctionCallAssignmentStatementContext 
ctx, String functionName) {
+               ArrayList<ParameterExpression> paramExpression = 
helper.getParameterExpressionList(ctx.paramExprs);
+               if(paramExpression.size() != 1) {
+                       helper.notifyErrorListeners(functionName + "() has only 
one parameter", ctx.start);
+                       return;
+               }
+               Expression expr = paramExpression.get(0).getExpr();
+               if(expr == null) {
+                       helper.notifyErrorListeners("cannot process " + 
functionName + "() function", ctx.start);
+                       return;
+               }
+               try {
+                       int line = ctx.start.getLine();
+                       int col = ctx.start.getCharPositionInLine();
+                       ctx.info.stmt = new PrintStatement(functionName, expr, 
line, col, line, col);
+               } catch (LanguageException e) {
+                       helper.notifyErrorListeners("cannot process " + 
functionName + "() function", ctx.start);
+                       return;
+               }
+       }
+       
+       private void setOutputStatement(FunctionCallAssignmentStatementContext 
ctx) {
+               ArrayList<ParameterExpression> paramExpression = 
helper.getParameterExpressionList(ctx.paramExprs);
+               if(paramExpression.size() < 2){
+                       helper.notifyErrorListeners("incorrect usage of load 
function (atleast 2 arguments required)", ctx.start);
+                       return;
+               }
+               if(paramExpression.get(0).getExpr() instanceof DataIdentifier) {
+                       String fileName = helper.getCurrentFileName();
+                       int line = ctx.start.getLine();
+                       int col = ctx.start.getCharPositionInLine();
+                       HashMap<String, Expression> varParams = new 
HashMap<String, Expression>();
+                       varParams.put(DataExpression.IO_FILENAME, 
paramExpression.get(1).getExpr());
+                       for(int i = 2; i < paramExpression.size(); i++) {
+                               // DataExpression.FORMAT_TYPE, 
DataExpression.DELIM_DELIMITER, DataExpression.DELIM_HAS_HEADER_ROW,  
DataExpression.DELIM_SPARSE
+                               varParams.put(paramExpression.get(i).getName(), 
paramExpression.get(i).getExpr());
+                       }
+                       
+                       DataExpression  dataExpression = new 
DataExpression(DataOp.WRITE, varParams, fileName, line, col, line, col);
+                       ctx.info.stmt = new  OutputStatement((DataIdentifier) 
paramExpression.get(0).getExpr(), DataOp.WRITE, fileName, line, col, line, col);
+                       setFileLineColumn(ctx.info.stmt, ctx);
+                       
((OutputStatement)ctx.info.stmt).setExprParams(dataExpression);
+                       return;
+               }
+               
+               helper.notifyErrorListeners("incorrect usage of write 
function", ctx.start);
+               return;
+               
+       }
+
+       private boolean inDefaultNamespace(String namespace) {
+               return namespace.compareTo(DMLProgram.DEFAULT_NAMESPACE) == 0;
+       }
+       
+       // Returns 0, 1 or -1 (for error)
+       private int getAxis(ParameterizedExpressionContext ctx) {
+               if(ctx.paramName != null && ctx.paramName.getText() != null && 
!ctx.paramName.getText().isEmpty()) {
+                       if(ctx.paramName.getText().compareTo("axis") != 0) {
+                               return -1;
+                       }
+               }
+               
+               String val = ctx.paramVal.getText();
+               if(val != null && val.compareTo("0") == 0) {
+                       return 0;
+               }
+               else if(val != null && val.compareTo("1") == 0) {
+                       return 1;
+               }
+               
+               return -1;
+       }
+       
+       private String getPythonAggFunctionNames(String functionName, int axis) 
{
+               if(axis != 0 && axis != 1) {
+                       return functionName;
+               }
+               // axis=0 maps to column-wise computation and axis=1 maps to 
row-wise computation
+               
+               if(functionName.compareTo("sum") == 0) {
+                       return axis == 0 ? "colSums" : "rowSums"; 
+               }
+               else if(functionName.compareTo("mean") == 0) {
+                       return axis == 0 ? "colMeans" : "rowMeans"; 
+               }
+               else if(functionName.compareTo("avg") == 0) {
+                       return axis == 0 ? "colMeans" : "rowMeans";
+               }
+               else if(functionName.compareTo("max") == 0) {
+                       return axis == 0 ? "colMaxs" : "rowMaxs";
+               }
+               else if(functionName.compareTo("min") == 0) {
+                       return axis == 0 ? "colMins" : "rowMins";
+               }
+               else if(functionName.compareTo("argmin") == 0) {
+                       return axis == 0 ? "Not Supported" : "rowIndexMin";
+               }
+               else if(functionName.compareTo("argmax") == 0) {
+                       return axis == 0 ? "Not Supported" : "rowIndexMax";
+               }
+               else if(functionName.compareTo("cumsum") == 0) {
+                       return axis == 0 ?  "cumsum" : "Not Supported";
+               }
+               else if(functionName.compareTo("transpose") == 0) {
+                       return axis == 0 ?  "Not Supported" : "Not Supported";
+               }
+               else if(functionName.compareTo("trace") == 0) {
+                       return axis == 0 ?  "Not Supported" : "Not Supported";
+               }
+               else {
+                       return functionName;
+               }
+       }
+       
+       private ConvertedDMLSyntax 
convertPythonBuiltinFunctionToDMLSyntax(String namespace, String functionName, 
ArrayList<ParameterExpression> paramExpression, 
+               List<ParameterizedExpressionContext> paramCtx, Token fnName, 
String fileName, int line, int col) {
+               // 
===========================================================================================
+               // Check function name, namespace, parameters (#params & 
possible values) and throw useful hints
+               if(inDefaultNamespace(namespace) && 
functionName.compareTo("len") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts 1 arguments", fnName);
+                               return null;
+                       }
+                       functionName = "length";
+               }
+               else if(functionName.compareTo("sum") == 0 || 
functionName.compareTo("mean") == 0 || functionName.compareTo("avg") == 0 ||
+                               functionName.compareTo("min") == 0 || 
functionName.compareTo("max") == 0  || 
+                               functionName.compareTo("argmax") == 0 || 
functionName.compareTo("argmin") == 0 ||
+                               functionName.compareTo("cumsum") == 0 || 
functionName.compareTo("transpose") == 0 || functionName.compareTo("trace") == 
0) {
+                       // 0 maps row-wise computation and 1 maps to 
column-wise computation
+                       
+                       // can mean sum of all cells or row-wise or columnwise 
sum
+                       if(inDefaultNamespace(namespace) && 
paramExpression.size() == 1) {
+                               // sum(x) => sum(x)
+                               // otherwise same function name
+                               if(functionName.compareTo("avg") == 0) {
+                                       functionName = "mean";
+                               }
+                               else if(functionName.compareTo("transpose") == 
0) {
+                                       functionName = "t";
+                               }
+                               else if(functionName.compareTo("argmax") == 0 
|| functionName.compareTo("argmin") == 0 || functionName.compareTo("cumsum") == 
0) {
+                                       helper.notifyErrorListeners("The 
builtin function \'" + functionName + "\' for entire matrix is not supported", 
fnName);
+                                       return null;
+                               }
+                       }
+                       else if(!inDefaultNamespace(namespace) && 
paramExpression.size() == 0) {
+                               // x.sum() => sum(x)
+                               paramExpression = new 
ArrayList<ParameterExpression>();
+                               paramExpression.add(new 
ParameterExpression(null, new DataIdentifier(namespace)));
+                               // otherwise same function name
+                               if(functionName.compareTo("avg") == 0) {
+                                       functionName = "mean";
+                               }
+                               else if(functionName.compareTo("transpose") == 
0) {
+                                       functionName = "t";
+                               }
+                               else if(functionName.compareTo("argmax") == 0 
|| functionName.compareTo("argmin") == 0 || functionName.compareTo("cumsum") == 
0) {
+                                       helper.notifyErrorListeners("The 
builtin function \'" + functionName + "\' for entire matrix is not supported", 
fnName);
+                                       return null;
+                               }
+                       }
+                       else if(inDefaultNamespace(namespace) && 
paramExpression.size() == 2) {
+                               // sum(x, axis=1) => rowSums(x)
+                               int axis = getAxis(paramCtx.get(1));
+                               if(axis == -1 && (functionName.compareTo("min") 
== 0 || functionName.compareTo("max") == 0 )) {
+                                       // Do nothing
+                                       // min(2, 3)
+                               }
+                               else if(axis == -1) {
+                                       helper.notifyErrorListeners("The 
builtin function \'" + functionName + "\' for given arguments is not 
supported", fnName);
+                                       return null;
+                               }
+                               else {
+                                       ArrayList<ParameterExpression> temp = 
new ArrayList<ParameterExpression>();
+                                       temp.add(paramExpression.get(0));
+                                       paramExpression = temp;
+                                       functionName = 
getPythonAggFunctionNames(functionName, axis);
+                                       if(functionName.compareTo("Not 
Supported") == 0) {
+                                               
helper.notifyErrorListeners("The builtin function \'" + functionName + "\' for 
given arguments is not supported", fnName);
+                                               return null;
+                                       }
+                               }
+                       }
+                       else if(!inDefaultNamespace(namespace) && 
paramExpression.size() == 1) {
+                               // x.sum(axis=1) => rowSums(x)
+                               int axis = getAxis(paramCtx.get(0));
+                                if(axis == -1) {
+                                        helper.notifyErrorListeners("The 
builtin function \'" + functionName + "\' for given arguments is not 
supported", fnName);
+                                        return null;
+                                }
+                                else {
+                                        paramExpression = new 
ArrayList<ParameterExpression>();
+                                        paramExpression.add(new 
ParameterExpression(null, new DataIdentifier(namespace)));
+                                        functionName = 
getPythonAggFunctionNames(functionName, axis);
+                                        if(functionName.compareTo("Not 
Supported") == 0) {
+                                                
helper.notifyErrorListeners("The builtin function \'" + functionName + "\' for 
given arguments is not supported", fnName);
+                                                return null;
+                                        }
+                                }
+                       }
+                       else {
+                               helper.notifyErrorListeners("Incorrect number 
of arguments for the builtin function \'" + functionName + "\'.", fnName);
+                               return null;
+                       }
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("concatenate") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts 2 arguments (Note: concatenate append 
columns of two matrices)", fnName);
+                               return null;
+                       }
+                       functionName = "append";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("minimum") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts 2 arguments", fnName);
+                               return null;
+                       }
+                       functionName = "min";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("maximum") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts 2 arguments", fnName);
+                               return null;
+                       }
+                       functionName = "max";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(!inDefaultNamespace(namespace) && 
functionName.compareTo("shape") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts only 1 argument (0 or 1)", fnName);
+                               return null;
+                       }
+                       
+                       int axis = getAxis(paramCtx.get(0));
+                       if(axis == -1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts only 1 argument (0 or 1)", fnName);
+                               return null; 
+                       }
+                       paramExpression = new ArrayList<ParameterExpression>();
+                       paramExpression.add(new ParameterExpression(null, new 
DataIdentifier(namespace)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+                       if(axis == 0) {
+                               functionName = "nrow";
+                       }
+                       else if(axis == 1) {
+                               functionName = "ncol";
+                       }
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("random.normal") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (number of rows, 
number of columns, sparsity)", fnName);
+                               return null;
+                       }
+                       paramExpression.get(0).setName("rows");
+                       paramExpression.get(1).setName("cols");
+                       paramExpression.get(2).setName("sparsity");
+                       paramExpression.add(new 
org.apache.sysml.parser.ParameterExpression("pdf", new 
StringIdentifier("normal", fileName, line, col, line, col)));
+                       functionName = "rand";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("random.uniform") == 0) {
+                       if(paramExpression.size() != 5) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 5 arguments (number of rows, 
number of columns, sparsity, min, max)", fnName);
+                               return null;
+                       }
+                       paramExpression.get(0).setName("rows");
+                       paramExpression.get(1).setName("cols");
+                       paramExpression.get(2).setName("sparsity");
+                       paramExpression.get(3).setName("min");
+                       paramExpression.get(4).setName("max");
+                       paramExpression.add(new 
org.apache.sysml.parser.ParameterExpression("pdf", new 
StringIdentifier("uniform", fileName, line, col, line, col)));
+                       functionName = "rand";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("full") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (constant float 
value, number of rows, number of columns)", fnName);
+                               return null;
+                       }
+                       paramExpression.get(1).setName("rows");
+                       paramExpression.get(2).setName("cols");
+                       functionName = "matrix";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("matrix") == 0) {
+                       // This can either be string initializer or as.matrix 
function
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 1 argument (either str or 
float value)", fnName);
+                               return null;
+                       }
+                       
+                       if(paramExpression.get(0).getExpr() instanceof 
StringIdentifier) {
+                               String initializerString = 
((StringIdentifier)paramExpression.get(0).getExpr()).getValue().trim();
+                               if(!initializerString.startsWith("[") || 
!initializerString.endsWith("]")) {
+                                       helper.notifyErrorListeners("Incorrect 
initializer string for builtin function \'" + functionName + "\' (Eg: 
matrix(\"[1 2 3; 4 5 6]\"))", fnName);
+                                       return null;
+                               }
+                               int rows = 
StringUtils.countMatches(initializerString, ";") + 1;
+                               
+                               // Make sure user doesnot have pretty string
+                               initializerString = 
initializerString.replaceAll("; ", ";");
+                               initializerString = 
initializerString.replaceAll(" ;", ";");
+                               initializerString = 
initializerString.replaceAll("\\[ ", "\\[");
+                               initializerString = 
initializerString.replaceAll(" \\]", "\\]");
+                               
+                               // Each row has ncol-1 spaces
+                               // #spaces = nrow * (ncol-1)
+                               // ncol = (#spaces / nrow) + 1 
+                               int cols = 
(StringUtils.countMatches(initializerString, " ") / rows) + 1;
+                               
+                               initializerString = 
initializerString.replaceAll(";", " ");
+                               initializerString = 
initializerString.replaceAll("\\[", "");
+                               initializerString = 
initializerString.replaceAll("\\]", "");
+                               paramExpression = new 
ArrayList<ParameterExpression>();
+                               paramExpression.add(new 
ParameterExpression(null, new StringIdentifier(initializerString, fileName, 
line, col, line, col)));
+                               paramExpression.add(new 
ParameterExpression("rows", new IntIdentifier(rows, fileName, line, col, line, 
col)));
+                               paramExpression.add(new 
ParameterExpression("cols", new IntIdentifier(cols, fileName, line, col, line, 
col)));
+                       }
+                       else {
+                               functionName = "as.matrix";
+                       }
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("scalar") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 1 argument", fnName);
+                               return null;
+                       }
+                       functionName = "as.scalar";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("float") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 1 argument", fnName);
+                               return null;
+                       }
+                       functionName = "as.double";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("int") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 1 argument", fnName);
+                               return null;
+                       }
+                       functionName = "as.integer";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("bool") == 0) {
+                       if(paramExpression.size() != 1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 1 argument", fnName);
+                               return null;
+                       }
+                       functionName = "as.logical";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(!inDefaultNamespace(namespace) && 
functionName.compareTo("reshape") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (number of rows, 
number of columns)", fnName);
+                               return null;
+                       }
+                       paramExpression.get(0).setName("rows");
+                       paramExpression.get(1).setName("cols");
+                       
+                       ArrayList<ParameterExpression> temp = new 
ArrayList<ParameterExpression>();
+                       temp.add(new ParameterExpression(null, new 
DataIdentifier(namespace)));
+                       temp.add(paramExpression.get(0));
+                       temp.add(paramExpression.get(1));
+                       paramExpression = temp;
+                       
+                       functionName = "matrix";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("removeEmpty") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (matrix, axis=0 
or 1)", fnName);
+                               return null;
+                       }
+                       int axis = getAxis(paramCtx.get(1));
+                       if(axis == -1) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (matrix, axis=0 
or 1)", fnName);
+                               return null; 
+                       }
+                       StringIdentifier marginVal = null;
+                       if(axis == 0) {
+                               marginVal = new StringIdentifier("rows", 
fileName, line, col, line, col);
+                       }
+                       else {
+                               marginVal = new StringIdentifier("cols", 
fileName, line, col, line, col);
+                       }
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("margin");
+                       paramExpression.get(1).setExpr(marginVal);
+                       functionName = "removeEmpty";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("replace") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (matrix, scalar 
value that should be replaced (pattern), scalar value (replacement))", fnName);
+                               return null;
+                       }
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("pattern");
+                       paramExpression.get(2).setName("replacement");
+                       functionName = "replace";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("range") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (matrix, scalar 
value that should be replaced (pattern), scalar value (replacement))", fnName);
+                               return null;
+                       }
+                       functionName = "seq";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("norm.cdf") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (target, mean, 
sd)", fnName);
+                               return null;
+                       }
+                       functionName = "cumulativeProbability";
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("mean");
+                       paramExpression.get(2).setName("sd");
+                       paramExpression.add(new ParameterExpression("dist", new 
StringIdentifier("normal", fileName, line, col, line, col)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("expon.cdf") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (target, mean)", 
fnName);
+                               return null;
+                       }
+                       functionName = "cumulativeProbability";
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("mean");
+                       paramExpression.add(new ParameterExpression("dist", new 
StringIdentifier("exp", fileName, line, col, line, col)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("chi.cdf") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (target, df)", 
fnName);
+                               return null;
+                       }
+                       functionName = "cumulativeProbability";
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("df");
+                       paramExpression.add(new ParameterExpression("dist", new 
StringIdentifier("chisq", fileName, line, col, line, col)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("f.cdf") == 0) {
+                       if(paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 3 arguments (target, df1, 
df2)", fnName);
+                               return null;
+                       }
+                       functionName = "cumulativeProbability";
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("df1");
+                       paramExpression.get(2).setName("df2");
+                       paramExpression.add(new ParameterExpression("dist", new 
StringIdentifier("f", fileName, line, col, line, col)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("t.cdf") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments (target, df)", 
fnName);
+                               return null;
+                       }
+                       functionName = "cumulativeProbability";
+                       paramExpression.get(0).setName("target");
+                       paramExpression.get(1).setName("df");
+                       paramExpression.add(new ParameterExpression("dist", new 
StringIdentifier("t", fileName, line, col, line, col)));
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("percentile") == 0) {
+                       if(paramExpression.size() != 2 && 
paramExpression.size() != 3) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts either 2 or 3 arguments", fnName);
+                               return null;
+                       }
+                       functionName = "quantile";
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("arcsin") == 0) {
+                       functionName = "asin";
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("arccos") == 0) {
+                       functionName = "acos";
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("arctan") == 0) {
+                       functionName = "atan";
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("load") == 0) {
+                       functionName = "read";
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("eigen") == 0) {
+                       functionName = "eig";
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("power") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments", fnName);
+                               return null;
+                       }
+               }
+               else if(inDefaultNamespace(namespace) && 
functionName.compareTo("dot") == 0) {
+                       if(paramExpression.size() != 2) {
+                               helper.notifyErrorListeners("The builtin 
function \'" + functionName + "\' accepts exactly 2 arguments", fnName);
+                               return null;
+                       }
+               }
+               
+               ConvertedDMLSyntax retVal = new ConvertedDMLSyntax();
+               retVal.namespace = namespace;
+               retVal.functionName = functionName;
+               retVal.paramExpression = paramExpression;
+               return retVal;
+       }
+
+       class ConvertedDMLSyntax {
+               public String namespace;
+               public String functionName;
+               public ArrayList<ParameterExpression> paramExpression;
+       };
+       
+       private Expression getOperatorExpression(String namespace, String 
functionName, ArrayList<ParameterExpression> paramExpression) {
+               String dmlOperator = null;
+               
+               if(inDefaultNamespace(namespace) && 
functionName.compareTo("dot") == 0) {
+                       if(paramExpression.size() == 2) {
+                               dmlOperator = "%*%";
+                       }
+               }
+
+               if(dmlOperator != null) {
+                       Expression.BinaryOp bop = 
Expression.getBinaryOp(dmlOperator);
+                       Expression expr = new BinaryExpression(bop);
+                       
((BinaryExpression)expr).setLeft(paramExpression.get(0).getExpr());
+                       
((BinaryExpression)expr).setRight(paramExpression.get(1).getExpr());
+                       return expr;
+               }
+               
+               return null;
+       }
+       
+       @Override
+       public void 
exitFunctionCallAssignmentStatement(FunctionCallAssignmentStatementContext ctx) 
{
+               ArrayList<String> names = 
helper.getQualifiedNames(ctx.name.getText());
+               if(names == null) {
+                       helper.notifyErrorListeners("incorrect function name 
(only namespace.functionName allowed. Hint: If you are trying to use builtin 
functions, you can skip the namespace)", ctx.name);
+                       return;
+               }
+               String namespace = names.get(0);
+               String functionName = names.get(1);
+               
+               if((functionName.compareTo("print") == 0 || 
functionName.compareTo("stop") == 0 ) && 
namespace.compareTo(DMLProgram.DEFAULT_NAMESPACE) == 0) {
+                       setPrintStatement(ctx, functionName);
+                       return;
+               }
+               else if(functionName.compareTo("save") == 0 && 
namespace.compareTo(DMLProgram.DEFAULT_NAMESPACE) == 0) {
+                       setOutputStatement(ctx);
+                       return;
+               }
+               
+               boolean ignoreLValue = false;
+               if(ctx.targetList == null || ctx.targetList.size() == 0 || 
ctx.targetList.get(0).isEmpty()) {
+                       helper.notifyErrorListeners("function call needs to 
have lvalue (Quickfix: change it to \'tmpVar = " + functionName + "(...)\')", 
ctx.name);
+                       return;
+               }
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               
+               ArrayList<ParameterExpression> paramExpression = 
helper.getParameterExpressionList(ctx.paramExprs);
+               
+               ConvertedDMLSyntax convertedSyntax = 
convertPythonBuiltinFunctionToDMLSyntax(namespace, functionName, 
paramExpression, ctx.paramExprs, ctx.name, fileName, line, col);
+               if(convertedSyntax == null) {
+                       return;
+               }
+               else {
+                       namespace = convertedSyntax.namespace;
+                       functionName = convertedSyntax.functionName;
+                       paramExpression = convertedSyntax.paramExpression;
+               }
+               
+               // 
===========================================================================================
+               FunctionCallIdentifier functCall = new 
FunctionCallIdentifier(paramExpression);
+               try {
+                       functCall.setFunctionName(functionName);
+                       functCall.setFunctionNamespace(namespace);
+               } catch (ParseException e1) {
+                       helper.notifyErrorListeners("unable to process function 
" + functionName, ctx.start);
+                        return;
+               }
+               
+               DataIdentifier target = null; 
+               if(!ignoreLValue) {
+                       if(ctx.targetList.get(0).dataInfo.expr instanceof 
DataIdentifier) {
+                               target = (DataIdentifier) 
ctx.targetList.get(0).dataInfo.expr;
+                       }
+                       else {
+                               helper.notifyErrorListeners("incorrect lvalue 
... strange", ctx.targetList.get(0).start);
+                               //target = new DataIdentifier(); // so as not 
to avoid null pointer
+                               return;
+                       }
+               }
+               
+               Expression operatorExpr = getOperatorExpression(namespace, 
functionName, paramExpression);
+               if(operatorExpr != null) {
+                       setFileLineColumn(operatorExpr, ctx);
+                       setAssignmentStatement(target, operatorExpr, ctx);
+                       return;
+               }
+               
+               //Note: In contrast to the dml parser, namespace and function 
names are separated by '.' not '::'.  
+               //Hence, we have to include a whitelist of function names to 
handle builtins like 'as.scalar'.          
+               String[] whitelist = new 
String[]{"as.matrix","as.scalar","as.double","as.integer","as.logical"};
+               boolean isWhitelisted = 
Arrays.asList(whitelist).contains(functionName);
+               
+               if(    !functionName.contains(".") || isWhitelisted 
+                       || 
functionName.startsWith(DMLProgram.DEFAULT_NAMESPACE) ) 
+               {
+                       // In global namespace, so it can be a builtin function
+                       if(!helper.validateBuiltinFunctions(ctx)) {
+                               return; // it is a built-in function and 
validation failed, so donot proceed ahead.
+                       }
+                       // Double verification: verify passed function name is 
a (non-parameterized) built-in function.
+                       try 
+                       {
+                               // builtin functions
+                               BuiltinFunctionExpression bife = 
BuiltinFunctionExpression.getBuiltinFunctionExpression(functionName, 
functCall.getParamExprs(), fileName, line, col, line, col);
+                               if (bife != null) {
+                                       setAssignmentStatement(target, bife, 
ctx);
+                                       return;
+                               }
+                               
+                               // parameterized builtin functions
+                               ParameterizedBuiltinFunctionExpression pbife = 
ParameterizedBuiltinFunctionExpression.getParamBuiltinFunctionExpression(functionName,
 functCall.getParamExprs(), fileName, line, col, line, col);
+                               if (pbife != null) {
+                                       setAssignmentStatement(target, pbife, 
ctx);
+                                       return;
+                               }
+                               
+                               // built-in data expressions, e.g. read
+                               DataExpression dbife = 
DataExpression.getDataExpression(functionName, functCall.getParamExprs(), 
fileName, line, col, line, col);
+                               if (dbife != null){
+                                       setAssignmentStatement(target, dbife, 
ctx);
+                                       return;
+                               }
+                       } 
+                       catch(Exception e) {
+                               helper.notifyErrorListeners("unable to process 
builtin function expression " + functionName  + ":" + e.getMessage(), 
ctx.start);
+                               return ;
+                       }
+               }
+               
+               setAssignmentStatement(target, functCall, ctx);
+       }
+       
+       
+       @Override
+       public void 
exitBuiltinFunctionExpression(BuiltinFunctionExpressionContext ctx) {
+               // Double verification: verify passed function name is a 
(non-parameterized) built-in function.
+               ArrayList<String> names = 
helper.getQualifiedNames(ctx.name.getText());
+               if(names == null) {
+                       helper.notifyErrorListeners("incorrect function name 
(only namespace.functionName allowed. Hint: If you are trying to use builtin 
functions, you can skip the namespace)", ctx.name);
+                       return;
+               }
+               String namespace = names.get(0);
+               String functionName = names.get(1);
+               
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               ArrayList<ParameterExpression> paramExpression = 
helper.getParameterExpressionList(ctx.paramExprs);
+
+               ConvertedDMLSyntax convertedSyntax = 
convertPythonBuiltinFunctionToDMLSyntax(namespace, functionName, 
paramExpression, ctx.paramExprs, ctx.name, fileName, line, col);
+               if(convertedSyntax == null) {
+                       return;
+               }
+               else {
+                       namespace = convertedSyntax.namespace;
+                       functionName = convertedSyntax.functionName;
+                       paramExpression = convertedSyntax.paramExpression;
+                       // System.out.println(ctx.name.getText() + ">>" + 
namespace + " " + functionName);
+               }
+               
+               Expression operatorExpr = getOperatorExpression(namespace, 
functionName, paramExpression);
+               if(operatorExpr != null) {
+                       ctx.info.expr = operatorExpr;
+                       setFileLineColumn(operatorExpr, ctx);
+                       return;
+               }
+               
+               try {
+                       BuiltinFunctionExpression bife = 
BuiltinFunctionExpression.getBuiltinFunctionExpression(functionName, 
paramExpression, fileName, line, col, line, col);
+                       if (bife != null){
+                               // It is a builtin function
+                               ctx.info.expr = bife;
+                               return;
+                       }
+                       
+                       ParameterizedBuiltinFunctionExpression pbife = 
ParameterizedBuiltinFunctionExpression.getParamBuiltinFunctionExpression(functionName,
 paramExpression, fileName, line, col, line, col);
+                       if (pbife != null){
+                               // It is a parameterized builtin function
+                               ctx.info.expr = pbife;
+                               return;
+                       }
+                       
+                       // built-in read, rand ...
+                       DataExpression dbife = 
DataExpression.getDataExpression(functionName, paramExpression, fileName, line, 
col, line, col);
+                       if (dbife != null){
+                               ctx.info.expr = dbife;
+                               return;
+                       }
+               } catch(Exception e) {
+                       helper.notifyErrorListeners("unable to process builtin 
function expression " + functionName + ":" + e.getMessage(), ctx.start);
+                       return ;
+               }
+               helper.notifyErrorListeners("only builtin functions allowed as 
part of expression", ctx.start);
+       }
+       
+       private void setMultiAssignmentStatement(ArrayList<DataIdentifier> 
target, Expression expression, StatementContext ctx) {
+               ctx.info.stmt = new MultiAssignmentStatement(target, 
expression);
+               ctx.info.stmt.setAllPositions(helper.getCurrentFileName(), 
ctx.start.getLine(), ctx.start.getCharPositionInLine(), ctx.start.getLine(), 
ctx.start.getCharPositionInLine());
+               setFileLineColumn(ctx.info.stmt, ctx);
+       }
+
+       @Override
+       public void exitFunctionCallMultiAssignmentStatement(
+                       FunctionCallMultiAssignmentStatementContext ctx) {
+               ArrayList<String> names = 
helper.getQualifiedNames(ctx.name.getText());
+               if(names == null) {
+                       helper.notifyErrorListeners("incorrect function name 
(only namespace.functionName allowed. Hint: If you are trying to use builtin 
functions, you can skip the namespace)", ctx.name);
+                       return;
+               }
+               String namespace = names.get(0);
+               String functionName = names.get(1);
+               
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               
+               ArrayList<ParameterExpression> paramExpression = 
helper.getParameterExpressionList(ctx.paramExprs);
+               ConvertedDMLSyntax convertedSyntax = 
convertPythonBuiltinFunctionToDMLSyntax(namespace, functionName, 
paramExpression, ctx.paramExprs, ctx.name, fileName, line, col);
+               if(convertedSyntax == null) {
+                       return;
+               }
+               else {
+                       namespace = convertedSyntax.namespace;
+                       functionName = convertedSyntax.functionName;
+                       paramExpression = convertedSyntax.paramExpression;
+               }
+               
+               // No need to support dot() function since it will never return 
multi-assignment function
+               
+               FunctionCallIdentifier functCall = new 
FunctionCallIdentifier(paramExpression);
+               try {
+                       functCall.setFunctionName(functionName);
+                       functCall.setFunctionNamespace(namespace);
+               } catch (ParseException e1) {
+                       helper.notifyErrorListeners("unable to process function 
" + functionName, ctx.start);
+                       return;
+               }
+               
+               ArrayList<DataIdentifier> targetList = new 
ArrayList<DataIdentifier>();
+               for(DataIdentifierContext dataCtx : ctx.targetList) {
+                       if(dataCtx.dataInfo.expr instanceof DataIdentifier) {
+                               targetList.add((DataIdentifier) 
dataCtx.dataInfo.expr);
+                       }
+                       else {
+                               helper.notifyErrorListeners("incorrect lvalue 
... strange", dataCtx.start);
+                               //target = new DataIdentifier(); // so as not 
to avoid null pointer
+                               return;
+                       }
+               }
+               
+               if(!functionName.contains(".") || 
functionName.startsWith(DMLProgram.DEFAULT_NAMESPACE)) {
+                       // In global namespace, so it can be a builtin function
+                       // Double verification: verify passed function name is 
a (non-parameterized) built-in function.
+                       try {
+                               BuiltinFunctionExpression bife = 
BuiltinFunctionExpression.getBuiltinFunctionExpression(functionName, 
functCall.getParamExprs(), fileName, line, col, line, col);
+                               if (bife != null){
+                                       // It is a builtin function
+                                       setMultiAssignmentStatement(targetList, 
bife, ctx);
+                                       return;
+                               }
+                               
+                               ParameterizedBuiltinFunctionExpression pbife = 
ParameterizedBuiltinFunctionExpression.getParamBuiltinFunctionExpression(functionName,
 functCall.getParamExprs(), fileName, line, col, line, col);
+                               if (pbife != null){
+                                       // It is a parameterized builtin 
function
+                                       setMultiAssignmentStatement(targetList, 
pbife, ctx);
+                                       return;
+                               }
+                               
+                               // built-in read, rand ...
+                               DataExpression dbife = 
DataExpression.getDataExpression(functionName, functCall.getParamExprs(), 
fileName, line, col, line, col);
+                               if (dbife != null){
+                                       setMultiAssignmentStatement(targetList, 
dbife, ctx);
+                                       return;
+                               }
+                       } catch(Exception e) {
+                               helper.notifyErrorListeners("unable to process 
builtin function expression " + functionName  + ":" + e.getMessage(), 
ctx.start);
+                               return;
+                       }
+               }
+               
+               setMultiAssignmentStatement(targetList, functCall, ctx);
+       }
+       
+       private StatementBlock getStatementBlock(Statement current) {
+               return PyDMLParserWrapper.getStatementBlock(current);
+       }
+       
+       @Override
+       public void exitIfStatement(IfStatementContext ctx) {
+               IfStatement ifStmt = new IfStatement();
+               ConditionalPredicate predicate = new 
ConditionalPredicate(ctx.predicate.info.expr);
+               ifStmt.setConditionalPredicate(predicate);
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               ifStmt.setAllPositions(fileName, line, col, line, col);
+               
+               if(ctx.ifBody.size() > 0) {
+                       for(StatementContext stmtCtx : ctx.ifBody) {
+                               
ifStmt.addStatementBlockIfBody(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       ifStmt.mergeStatementBlocksIfBody();
+               }
+               
+               if(ctx.elseBody.size() > 0) {
+                       for(StatementContext stmtCtx : ctx.elseBody) {
+                               
ifStmt.addStatementBlockElseBody(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       ifStmt.mergeStatementBlocksElseBody();
+               }
+               
+               ctx.info.stmt = ifStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+       }
+       
+       @Override
+       public void exitWhileStatement(WhileStatementContext ctx) {
+               WhileStatement whileStmt = new WhileStatement();
+               ConditionalPredicate predicate = new 
ConditionalPredicate(ctx.predicate.info.expr);
+               whileStmt.setPredicate(predicate);
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               whileStmt.setAllPositions(fileName, line, col, line, col);
+               
+               if(ctx.body.size() > 0) {
+                       for(StatementContext stmtCtx : ctx.body) {
+                               
whileStmt.addStatementBlock(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       whileStmt.mergeStatementBlocks();
+               }
+               
+               ctx.info.stmt = whileStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+       }
+       
+       @Override
+       public void exitForStatement(ForStatementContext ctx) {
+               ForStatement forStmt = new ForStatement();
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               
+               DataIdentifier iterVar = new 
DataIdentifier(ctx.iterVar.getText());
+               HashMap<String, String> parForParamValues = null;
+               Expression incrementExpr = new IntIdentifier(1, fileName, line, 
col, line, col);
+               if(ctx.iterPred.info.increment != null) {
+                       incrementExpr = ctx.iterPred.info.increment;
+               }
+               IterablePredicate predicate = new IterablePredicate(iterVar, 
ctx.iterPred.info.from, ctx.iterPred.info.to, incrementExpr, parForParamValues, 
fileName, line, col, line, col);
+               forStmt.setPredicate(predicate);
+               
+               if(ctx.body.size() > 0) {
+                       for(StatementContext stmtCtx : ctx.body) {
+                               
forStmt.addStatementBlock(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       forStmt.mergeStatementBlocks();
+               }
+               ctx.info.stmt = forStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+       }
+
+       @Override
+       public void exitParForStatement(ParForStatementContext ctx) {
+               ParForStatement parForStmt = new ParForStatement();
+               String fileName = helper.getCurrentFileName();
+               int line = ctx.start.getLine();
+               int col = ctx.start.getCharPositionInLine();
+               
+               DataIdentifier iterVar = new 
DataIdentifier(ctx.iterVar.getText());
+               HashMap<String, String> parForParamValues = new HashMap<String, 
String>();
+               if(ctx.parForParams != null && ctx.parForParams.size() > 0) {
+                       for(StrictParameterizedExpressionContext parForParamCtx 
: ctx.parForParams) {
+                               
parForParamValues.put(parForParamCtx.paramName.getText(), 
parForParamCtx.paramVal.getText());
+                       }
+               }
+               
+               Expression incrementExpr = new IntIdentifier(1, fileName, line, 
col, line, col);
+               
+               if( ctx.iterPred.info.increment != null ) {
+                       incrementExpr = ctx.iterPred.info.increment;
+               }
+               IterablePredicate predicate = new IterablePredicate(iterVar, 
ctx.iterPred.info.from, ctx.iterPred.info.to, incrementExpr, parForParamValues, 
fileName, line, col, line, col);
+               parForStmt.setPredicate(predicate);
+               if(ctx.body.size() > 0) {
+                       for(StatementContext stmtCtx : ctx.body) {
+                               
parForStmt.addStatementBlock(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       parForStmt.mergeStatementBlocks();
+               }
+               ctx.info.stmt = parForStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+       }
+       
+       
+       
+
+       // 
----------------------------------------------------------------------
+       @Override
+       public void exitMl_type(Ml_typeContext ctx) { }
+       
+       private ArrayList<DataIdentifier> 
getFunctionParameters(List<TypedArgNoAssignContext> ctx) {
+               ArrayList<DataIdentifier> retVal = new 
ArrayList<DataIdentifier>();
+               for(TypedArgNoAssignContext paramCtx : ctx) {
+                       DataIdentifier dataId = new 
DataIdentifier(paramCtx.paramName.getText());
+                       String dataType = null;
+                       String valueType = null;
+                       
+                       if(paramCtx.paramType == null || 
paramCtx.paramType.dataType() == null 
+                                       || 
paramCtx.paramType.dataType().getText() == null || 
paramCtx.paramType.dataType().getText().isEmpty()) {
+                               dataType = "scalar";
+                       }
+                       else {
+                               dataType = 
paramCtx.paramType.dataType().getText();
+                       }
+                       
+                       if(dataType.compareTo("matrix") == 0) {
+                               // matrix
+                               dataId.setDataType(DataType.MATRIX);
+                       }
+                       else if(dataType.compareTo("scalar") == 0) {
+                               // scalar
+                               dataId.setDataType(DataType.SCALAR);
+                       }
+                       else {
+                               helper.notifyErrorListeners("invalid datatype " 
+ dataType, paramCtx.start);
+                               return null;
+                       }
+                       
+                       valueType = paramCtx.paramType.valueType().getText();
+                       if(valueType.compareTo("int") == 0) {
+                               dataId.setValueType(ValueType.INT);
+                       }
+                       else if(valueType.compareTo("str") == 0) {
+                               dataId.setValueType(ValueType.STRING);
+                       }
+                       else if(valueType.compareTo("bool") == 0) {
+                               dataId.setValueType(ValueType.BOOLEAN);
+                       }
+                       else if(valueType.compareTo("float") == 0) {
+                               dataId.setValueType(ValueType.DOUBLE);
+                       }
+                       else {
+                               helper.notifyErrorListeners("invalid valuetype 
" + valueType, paramCtx.start);
+                               return null;
+                       }
+                       retVal.add(dataId);
+               }
+               return retVal;
+       }
+       
+       @Override
+       public void 
exitInternalFunctionDefExpression(InternalFunctionDefExpressionContext ctx) {
+               FunctionStatement functionStmt = new FunctionStatement();
+               
+               ArrayList<DataIdentifier> functionInputs  = 
getFunctionParameters(ctx.inputParams);
+               functionStmt.setInputParams(functionInputs);
+               
+               // set function outputs
+               ArrayList<DataIdentifier> functionOutputs = 
getFunctionParameters(ctx.outputParams);
+               functionStmt.setOutputParams(functionOutputs);
+               
+               // set function name
+               functionStmt.setName(ctx.name.getText());
+               
+               
+               if(ctx.body.size() > 0) {
+                       // handle function body
+                       // Create arraylist of one statement block
+                       ArrayList<StatementBlock> body = new 
ArrayList<StatementBlock>();
+                       for(StatementContext stmtCtx : ctx.body) {
+                               body.add(getStatementBlock(stmtCtx.info.stmt));
+                       }
+                       functionStmt.setBody(body);
+                       functionStmt.mergeStatementBlocks();
+               }
+               else {
+                       helper.notifyErrorListeners("functions with no 
statements are not allowed", ctx.start);
+                       return;
+               }
+               
+               ctx.info.stmt = functionStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+               ctx.info.functionName = ctx.name.getText();
+       }
+       
+       @Override
+       public void 
exitExternalFunctionDefExpression(ExternalFunctionDefExpressionContext ctx) {
+               ExternalFunctionStatement functionStmt = new 
ExternalFunctionStatement();
+               
+               ArrayList<DataIdentifier> functionInputs  = 
getFunctionParameters(ctx.inputParams);
+               functionStmt.setInputParams(functionInputs);
+               
+               // set function outputs
+               ArrayList<DataIdentifier> functionOutputs = 
getFunctionParameters(ctx.outputParams);
+               functionStmt.setOutputParams(functionOutputs);
+               
+               // set function name
+               functionStmt.setName(ctx.name.getText());
+               
+               // set other parameters
+               HashMap<String, String> otherParams = new 
HashMap<String,String>();
+               boolean atleastOneClassName = false;
+               for(StrictParameterizedKeyValueStringContext otherParamCtx : 
ctx.otherParams){
+                       String paramName = otherParamCtx.paramName.getText();
+                       String val = "";
+                       String text = otherParamCtx.paramVal.getText();
+                       // First unquote the string
+                       if(     (text.startsWith("\"") && text.endsWith("\"")) 
||
+                               (text.startsWith("\'") && text.endsWith("\'"))) 
{
+                               if(text.length() > 2) {
+                                       val = text.substring(1, 
text.length()-1);
+                               }
+                               // Empty value allowed
+                       }
+                       else {
+                               helper.notifyErrorListeners("the value of user 
parameter for external function should be of type str", ctx.start);
+                               return;
+                       }
+                       otherParams.put(paramName, val);
+                       if(paramName.compareTo("classname") == 0) {
+                               atleastOneClassName = true;
+                       }
+               }
+               functionStmt.setOtherParams(otherParams);
+               if(!atleastOneClassName) {
+                       helper.notifyErrorListeners("the parameter 
\'className\' needs to be passed for defExternal", ctx.start);
+                       return;
+               }
+                               
+               ctx.info.stmt = functionStmt;
+               setFileLineColumn(ctx.info.stmt, ctx);
+               ctx.info.functionName = ctx.name.getText();
+       }
+       
+       
+       @Override
+       public void exitPathStatement(PathStatementContext ctx) {
+               PathStatement stmt = new PathStatement(ctx.pathValue.getText());
+               String filePath = ctx.pathValue.getText();
+               if((filePath.startsWith("\"") && filePath.endsWith("\"")) || 
+                               filePath.startsWith("'") && 
filePath.endsWith("'")) {   
+                       filePath = filePath.substring(1, filePath.length()-1);
+               }
+               
+               _workingDir = filePath;
+               ctx.info.stmt = stmt;
+       }
+       
+       @Override
+       public void 
exitIfdefAssignmentStatement(IfdefAssignmentStatementContext ctx) {
+               if(!ctx.commandLineParam.getText().startsWith("$")) {
+                       helper.notifyErrorListeners("the first argument of 
ifdef function should be a commandline argument parameter (which starts with 
$)", ctx.commandLineParam.start);
+                       return;
+               }
+               
+               if(ctx.targetList == null || ctx.targetList.size() != 1) {
+                       helper.notifyErrorListeners("incorrect parsing for 
ifdef function", ctx.start);
+                       return;
+               }
+               String targetListText = ctx.targetList.get(0).getText(); 
+               if(targetListText.startsWith("$")) {
+                       helper.notifyErrorListeners("lhs of ifdef function 
cannot be a commandline parameters. Use local variable instead", ctx.start);
+                       return;
+               }
+               
+               DataIdentifier target = null; 
+               if(ctx.targetList.get(0).dataInfo.expr instanceof 
DataIdentifier) {
+                       target = (DataIdentifier) 
ctx.targetList.get(0).dataInfo.expr;
+                       Expression source = null;
+                       if(ctx.commandLineParam.dataInfo.expr != null) {
+                               // Since commandline parameter is set
+                               // The check of following is done in 
fillExpressionInfoCommandLineParameters:
+                               // Command line param cannot be empty string
+                               // If you want to pass space, please quote it
+                               source = ctx.commandLineParam.dataInfo.expr;
+                       }
+                       else {
+                               source = ctx.source.info.expr;
+                       }
+                       
+                       int line = ctx.start.getLine();
+                       int col = ctx.start.getCharPositionInLine();
+                       try {
+                               ctx.info.stmt = new AssignmentStatement(target, 
source, line, col, line, col);
+                               setFileLineColumn(ctx.info.stmt, ctx);
+                       } catch (LanguageException e) {
+                               helper.notifyErrorListeners("invalid assignment 
for ifdef function", ctx.targetList.get(0).start);
+                               return;
+                       } 
+                       
+               }
+               else {
+                       helper.notifyErrorListeners("incorrect lvalue in ifdef 
function... strange", ctx.targetList.get(0).start);
+                       return;
+               }
+               
+       }
+       
+       // 
----------------------------------------------------------------------
+       @Override
+       public void exitParameterizedExpression(ParameterizedExpressionContext 
ctx) { }
+
+
+       @Override
+       public void 
exitStrictParameterizedExpression(StrictParameterizedExpressionContext ctx) { }
+
+       @Override
+       public void exitTypedArgNoAssign(TypedArgNoAssignContext ctx) { }
+       @Override
+       public void 
enterIfdefAssignmentStatement(IfdefAssignmentStatementContext ctx) { }
+       @Override
+       public void enterMatrixDataTypeCheck(MatrixDataTypeCheckContext ctx) { }
+       @Override
+       public void exitMatrixDataTypeCheck(MatrixDataTypeCheckContext ctx) {
+               if(             ctx.ID().getText().compareTo("matrix") == 0 
+                               || ctx.ID().getText().compareTo("scalar") == 0
+                               ) {
+                       // Do nothing
+               }
+               else if(ctx.ID().getText().compareTo("Matrix") == 0)
+                       helper.notifyErrorListeners("incorrect datatype (Hint: 
use matrix instead of Matrix)", ctx.start);
+               else if(ctx.ID().getText().compareTo("Scalar") == 0)
+                       helper.notifyErrorListeners("incorrect datatype (Hint: 
use scalar instead of Scalar)", ctx.start);
+               else if(                ctx.ID().getText().compareTo("int") == 
0 
+                               || ctx.ID().getText().compareTo("str") == 0
+                               || ctx.ID().getText().compareTo("bool") == 0
+                               || ctx.ID().getText().compareTo("float") == 0
+                               ) {
+                       helper.notifyErrorListeners("expected datatype but 
found a valuetype (Hint: use matrix or scalar instead of " + ctx.ID().getText() 
+ ")", ctx.start);
+               }
+               else {
+                       helper.notifyErrorListeners("incorrect datatype 
(expected matrix or scalar)", ctx.start);
+               }
+       }
+       
+       @Override
+       public void 
enterBuiltinFunctionExpression(BuiltinFunctionExpressionContext ctx) {}
+       @Override
+       public void 
enterStrictParameterizedKeyValueString(StrictParameterizedKeyValueStringContext 
ctx) { }
+       @Override
+       public void 
exitStrictParameterizedKeyValueString(StrictParameterizedKeyValueStringContext 
ctx) {}
+       @Override
+       public void 
enterIterablePredicateColonExpression(IterablePredicateColonExpressionContext 
ctx) {}
+       @Override
+       public void 
enterIterablePredicateSeqExpression(IterablePredicateSeqExpressionContext ctx) 
{ }
+       
+       @Override
+       public void 
exitIterablePredicateColonExpression(IterablePredicateColonExpressionContext 
ctx) {
+               ctx.info.from = ctx.from.info.expr;
+               ctx.info.to = ctx.to.info.expr;
+               ctx.info.increment = null;
+       }
+       
+       @Override
+       public void 
exitIterablePredicateSeqExpression(IterablePredicateSeqExpressionContext ctx) {
+               if(ctx.ID().getText().compareTo("range") != 0) {
+                       helper.notifyErrorListeners("incorrect function:\'" + 
ctx.ID().getText() + "\'. expected \'range\'", ctx.start);
+                       return;
+               }
+               ctx.info.from = ctx.from.info.expr;
+               ctx.info.to = ctx.to.info.expr;
+               ctx.info.increment = ctx.increment.info.expr;           
+       }
+       
+       @Override
+       public void enterConstFalseExpression(ConstFalseExpressionContext ctx) 
{ }
+       @Override
+       public void enterConstTrueExpression(ConstTrueExpressionContext ctx) { }
+       
+       @Override
+       public void exitConstFalseExpression(ConstFalseExpressionContext ctx) {
+               boolean val = false;
+               int linePosition = ctx.start.getLine();
+               int charPosition = ctx.start.getCharPositionInLine();
+               ctx.info.expr = new BooleanIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       
+       @Override
+       public void exitConstTrueExpression(ConstTrueExpressionContext ctx) {
+               boolean val = true;
+               int linePosition = ctx.start.getLine();
+               int charPosition = ctx.start.getCharPositionInLine();
+               ctx.info.expr = new BooleanIdentifier(val, 
helper.getCurrentFileName(), linePosition, charPosition, linePosition, 
charPosition);
+               setFileLineColumn(ctx.info.expr, ctx);
+       }
+       
+       @Override
+       public void exitIgnoreNewLine(IgnoreNewLineContext ctx) {
+               // Introduce empty StatementInfo 
+               // This is later ignored by PyDMLParserWrapper
+               try {
+                       ctx.info.stmt = new AssignmentStatement(null, null, 0, 
0, 0, 0);
+                       ctx.info.stmt.setEmptyNewLineStatement(true);
+               } catch (LanguageException e) {
+                       e.printStackTrace();
+               }
+               
+       }
+       @Override
+       public void enterValueDataTypeCheck(ValueDataTypeCheckContext ctx) { }
+       @Override
+       public void exitValueDataTypeCheck(ValueDataTypeCheckContext ctx) {
+               if(             ctx.ID().getText().compareTo("int") == 0 
+                               || ctx.ID().getText().compareTo("str") == 0
+                               || ctx.ID().getText().compareTo("bool") == 0
+                               || ctx.ID().getText().compareTo("float") == 0
+                               ) {
+                       // Do nothing
+               }
+               else if(ctx.ID().getText().compareTo("integer") == 0)
+                       helper.notifyErrorListeners("incorrect valuetype (Hint: 
use int instead of integer)", ctx.start);
+               else if(ctx.ID().getText().compareTo("double") == 0)
+                       helper.notifyErrorListeners("incorrect valuetype (Hint: 
use float instead of double)", ctx.start);
+               else if(ctx.ID().getText().compareTo("boolean") == 0)
+                       helper.notifyErrorListeners("incorrect valuetype (Hint: 
use bool instead of boolean)", ctx.start);
+               else if(ctx.ID().getText().compareTo("string") == 0)
+                       helper.notifyErrorListeners("incorrect valuetype (Hint: 
use str instead of string)", ctx.start);
+               else {
+                       helper.notifyErrorListeners("incorrect valuetype 
(expected int, str, bool or float)", ctx.start);
+               }
+       }
+}

http://git-wip-us.apache.org/repos/asf/incubator-systemml/blob/c04fc99f/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidatorHelper.java
----------------------------------------------------------------------
diff --git 
a/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidatorHelper.java
 
b/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidatorHelper.java
new file mode 100644
index 0000000..5b14613
--- /dev/null
+++ 
b/src/main/java/org/apache/sysml/parser/pydml/PydmlSyntacticValidatorHelper.java
@@ -0,0 +1,101 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.sysml.parser.pydml;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.antlr.v4.runtime.Token;
+import org.apache.sysml.parser.DMLProgram;
+import 
org.apache.sysml.parser.pydml.PydmlParser.FunctionCallAssignmentStatementContext;
+import 
org.apache.sysml.parser.pydml.PydmlParser.ParameterizedExpressionContext;
+import 
org.apache.sysml.parser.pydml.PydmlSyntacticErrorListener.CustomDmlErrorListener;
+
+
+public class PydmlSyntacticValidatorHelper 
+{      
+       private CustomDmlErrorListener _errorListener = null;
+       public PydmlSyntacticValidatorHelper(CustomDmlErrorListener 
errorListener) {
+               this._errorListener = errorListener;
+       }
+       public void notifyErrorListeners(String message, int line, int 
charPositionInLine) {
+               this._errorListener.validationError(line, charPositionInLine, 
message);
+       }
+       
+       public void notifyErrorListeners(String message, Token op) {
+               this._errorListener.validationError(op.getLine(), 
op.getCharPositionInLine(), message);
+       }
+
+       public void raiseWarning(String message, Token op) {
+               this._errorListener.validationWarning(op.getLine(), 
op.getCharPositionInLine(), message);
+       }
+       
+       public String getCurrentFileName() {
+               return _errorListener.peekFileName();
+       }
+       
+       // Returns list of two elements <namespace, function names>, else null
+       public ArrayList<String> getQualifiedNames(String 
fullyQualifiedFunctionName) {
+               String [] fnNames = fullyQualifiedFunctionName.split("\\."); // 
instead of ::
+               String functionName = "";
+               String namespace = "";
+               if(fnNames.length == 1) {
+                       namespace = DMLProgram.DEFAULT_NAMESPACE;
+                       functionName = fnNames[0].trim();
+               }
+               else if(fnNames.length == 2) {
+                       namespace = fnNames[0].trim();
+                       functionName = fnNames[1].trim();
+               }
+               else
+                       return null;
+               
+               ArrayList<String> retVal = new ArrayList<String>();
+               retVal.add(namespace);
+               retVal.add(functionName);
+               return retVal;
+       }
+       
+       public boolean 
validateBuiltinFunctions(FunctionCallAssignmentStatementContext ctx) {
+               String functionName = ctx.name.getText().replaceAll(" ", 
"").trim();
+               if(functionName.compareTo("write") == 0 || 
functionName.compareTo(DMLProgram.DEFAULT_NAMESPACE + ".write") == 0) {
+                       return validateBuiltinWriteFunction(ctx);
+               }
+               return true;
+       }
+       
+       private boolean 
validateBuiltinWriteFunction(FunctionCallAssignmentStatementContext ctx) {
+               
+               return true;
+       }
+       
+       public ArrayList<org.apache.sysml.parser.ParameterExpression> 
getParameterExpressionList(List<ParameterizedExpressionContext> paramExprs) {
+               ArrayList<org.apache.sysml.parser.ParameterExpression> retVal = 
new ArrayList<org.apache.sysml.parser.ParameterExpression>();
+               for(ParameterizedExpressionContext ctx : paramExprs) {
+                       String paramName = null;
+                       if(ctx.paramName != null && ctx.paramName.getText() != 
null && !ctx.paramName.getText().isEmpty()) {
+                               paramName = ctx.paramName.getText();
+                       }
+                       org.apache.sysml.parser.ParameterExpression myArg = new 
org.apache.sysml.parser.ParameterExpression(paramName, ctx.paramVal.info.expr);
+                       retVal.add(myArg);
+               }
+               return retVal;
+       }
+}


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