/*
 * 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.
 */

options {


       STATIC = false;

}


PARSER_BEGIN(AQLPlusParser)

package org.apache.asterix.aqlplus.parser;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.asterix.common.config.MetadataConstants;
import org.apache.asterix.common.exceptions.AsterixException;
import org.apache.asterix.common.functions.FunctionSignature;
import org.apache.asterix.lang.aql.clause.DistinctClause;
import org.apache.asterix.lang.aql.clause.ForClause;
import org.apache.asterix.lang.aql.clause.JoinClause;
import org.apache.asterix.lang.aql.clause.MetaVariableClause;
import org.apache.asterix.lang.aql.expression.FLWOGRExpression;
import org.apache.asterix.lang.aql.expression.MetaVariableExpr;
import org.apache.asterix.lang.aql.expression.UnionExpr;
import org.apache.asterix.lang.common.base.Clause;
import org.apache.asterix.lang.common.base.Expression;
import org.apache.asterix.lang.common.base.Literal;
import org.apache.asterix.lang.common.base.Statement;
import org.apache.asterix.lang.common.clause.GroupbyClause;
import org.apache.asterix.lang.common.clause.LetClause;
import org.apache.asterix.lang.common.clause.LimitClause;
import org.apache.asterix.lang.common.clause.OrderbyClause;
import org.apache.asterix.lang.common.clause.WhereClause;
import org.apache.asterix.lang.common.context.RootScopeFactory;
import org.apache.asterix.lang.common.context.Scope;
import org.apache.asterix.lang.common.expression.AbstractAccessor;
import org.apache.asterix.lang.common.expression.CallExpr;
import org.apache.asterix.lang.common.expression.FieldAccessor;
import org.apache.asterix.lang.common.expression.FieldBinding;
import org.apache.asterix.lang.common.expression.GbyVariableExpressionPair;
import org.apache.asterix.lang.common.expression.IfExpr;
import org.apache.asterix.lang.common.expression.IndexAccessor;
import org.apache.asterix.lang.common.expression.ListConstructor;
import org.apache.asterix.lang.common.expression.LiteralExpr;
import org.apache.asterix.lang.common.expression.OperatorExpr;
import org.apache.asterix.lang.common.expression.OrderedListTypeDefinition;
import org.apache.asterix.lang.common.expression.QuantifiedExpression;
import org.apache.asterix.lang.common.expression.RecordConstructor;
import org.apache.asterix.lang.common.expression.RecordTypeDefinition;
import org.apache.asterix.lang.common.expression.TypeExpression;
import org.apache.asterix.lang.common.expression.TypeReferenceExpression;
import org.apache.asterix.lang.common.expression.UnaryExpr;
import org.apache.asterix.lang.common.expression.UnorderedListTypeDefinition;
import org.apache.asterix.lang.common.expression.VariableExpr;
import org.apache.asterix.lang.common.literal.DoubleLiteral;
import org.apache.asterix.lang.common.literal.FalseLiteral;
import org.apache.asterix.lang.common.literal.FloatLiteral;
import org.apache.asterix.lang.common.literal.IntegerLiteral;
import org.apache.asterix.lang.common.literal.LongIntegerLiteral;
import org.apache.asterix.lang.common.literal.NullLiteral;
import org.apache.asterix.lang.common.literal.StringLiteral;
import org.apache.asterix.lang.common.literal.TrueLiteral;
import org.apache.asterix.lang.common.parser.ScopeChecker;
import org.apache.asterix.lang.common.statement.DataverseDecl;
import org.apache.asterix.lang.common.statement.FunctionDecl;
import org.apache.asterix.lang.common.statement.LoadStatement;
import org.apache.asterix.lang.common.statement.Query;
import org.apache.asterix.lang.common.statement.SetStatement;
import org.apache.asterix.lang.common.statement.TypeDecl;
import org.apache.asterix.lang.common.statement.WriteStatement;
import org.apache.asterix.lang.common.struct.Identifier;
import org.apache.asterix.lang.common.struct.QuantifiedPair;
import org.apache.asterix.lang.common.struct.VarIdentifier;
import org.apache.hyracks.algebricks.core.algebra.expressions.IndexedNLJoinExpressionAnnotation;


public class AQLPlusParser extends ScopeChecker {

/*
    private void printHints(Token t) {
       //System.err.println("token="+t.image+"\t special="+t.specialToken);
       if (t.specialToken == null) return;
       Token tmp_t = t.specialToken;
       while (tmp_t.specialToken != null) tmp_t = tmp_t.specialToken;
       while (tmp_t != null) {
         System.out.println(tmp_t.image);
         tmp_t = tmp_t.next;
       }
    }
*/

    private static final String HASH_GROUP_BY_HINT = "hash";
    private static final String BROADCAST_JOIN_HINT = "bcast";
    private static final String INMEMORY_HINT = "inmem";
    private static final String INDEXED_NESTED_LOOP_JOIN_HINT = "indexnl";


    private static String getHint(Token t) {
       if (t.specialToken == null) {
         return null;
       }
       String s = t.specialToken.image;
       int n = s.length();
       if (n < 2) {
         return null;
       }
       return s.substring(1).trim();
    }

    public static void main(String args[]) throws ParseException, TokenMgrError, IOException, FileNotFoundException, AsterixException {
            File file = new File(args[0]);
            Reader fis = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
            AQLPlusParser parser = new AQLPlusParser(fis);
            List<Statement> st = parser.Statement();
    }

    public void initScope() {
            scopeStack.push(RootScopeFactory.createRootScope(this));
    }
}

PARSER_END(AQLPlusParser)


List<Statement> Statement() throws ParseException:
{
  Query query = null;
  // scopeStack.push(RootScopeFactory.createRootScope(this));
  initScope();
  List<Statement> decls = new ArrayList<Statement>();
}
{
    (
      (
        (
          "use"
            {
              decls.add(DataverseDeclaration());
            }
          | "declare"
            (   "function" {
                              decls.add(FunctionDeclaration());
                           }
              | "type"     {
                              decls.add(TypeDeclaration());
                           }
            )
          | "load" {
                       decls.add(LoadStatement());
                   }

          | "write" {
                       decls.add(WriteStatement());
                    }
          | "set" {
                       decls.add(SetStatement());
                    }
          |
            {
             decls.add(Query()) ;
           } ";"


        )*
      )

      <EOF>
    )
    {

     return decls;
    }
}

Statement SetStatement() throws ParseException:
{
  String pn = null;
  Statement stmt = null;
}
{
  <IDENTIFIER>  { pn = token.image; }
  <STRING_LITERAL>
    { String pv = removeQuotesAndEscapes(token.image); }
    ";"
  {
    return new SetStatement(pn, pv);
  }
}

Statement WriteStatement() throws ParseException:
{
  Identifier nodeName = null;
  String fileName = null;
  Identifier datasetName = null;
  Statement stmt = null;
  Query query;
}
{
  ( "output" "to"
    <IDENTIFIER> { nodeName = new Identifier(token.image); }
    ":" <STRING_LITERAL> {
             fileName = removeQuotesAndEscapes(token.image);
             stmt = new WriteStatement(nodeName, fileName, null);
         }
  ) ";"
    {
      return stmt;
    }
}

DataverseDecl DataverseDeclaration() throws ParseException:
{
  Identifier dvName = null;
}
{
  "dataverse" <IDENTIFIER> { defaultDataverse = token.image;}
  ";"
  {
    return new DataverseDecl(new Identifier(defaultDataverse));
  }
}

LoadStatement LoadStatement() throws ParseException:
{
  Identifier datasetName = null;
  boolean alreadySorted = false;
  String adapter;
  Map<String,String> properties = new HashMap<String,String>();
  String name;
  String value;
}
{
   <DATASET> <IDENTIFIER> { datasetName = new Identifier(token.image); }

   "using"
  (
    <STRING_LITERAL>
    {
      adapter = removeQuotesAndEscapes(token.image);
    }
    <LEFTPAREN>
    (
      (
        <LEFTPAREN>
        (
          <STRING_LITERAL>
          {
            name = removeQuotesAndEscapes(token.image);
          }
          "=" <STRING_LITERAL>
          {
            value = removeQuotesAndEscapes(token.image);
          }
        )
        <RIGHTPAREN>
        {
            properties.put(name, value);
        }
      )
      (
        "," <LEFTPAREN>
        (
          <STRING_LITERAL>
          {
            name = removeQuotesAndEscapes(token.image);
          }
          "=" <STRING_LITERAL>
          {
            value = removeQuotesAndEscapes(token.image);
          }
        )
        <RIGHTPAREN>
        {
            properties.put(name, value);
        }
      )*
    )?
    <RIGHTPAREN>
  )

    ("pre-sorted"
      {  alreadySorted = true; }
    )?

  ";"
  {
     return new LoadStatement(null, datasetName, adapter, properties, alreadySorted);
  }
}

TypeDecl TypeDeclaration() throws ParseException:
{
  Identifier ident;
  TypeExpression typeExpr;
}
{
  <IDENTIFIER>
  {
    ident = new Identifier(token.image.toString());
  }
  "as"
  ( typeExpr = TypeExpr() )
  {
    return new TypeDecl(null, ident, typeExpr);
  }
}

TypeExpression TypeExpr() throws ParseException:
{
  TypeExpression typeExpr = null;
}
{
  (
      typeExpr = RecordTypeDef()
    | typeExpr = TypeReference()
    | typeExpr = OrderedListTypeDef()
    | typeExpr = UnorderedListTypeDef()
  )
  {
    return typeExpr;
  }
}

RecordTypeDefinition RecordTypeDef() throws ParseException:
{
  RecordTypeDefinition recType = new RecordTypeDefinition();
  RecordTypeDefinition.RecordKind recordKind = null;
}
{
  ( "closed" { recordKind = RecordTypeDefinition.RecordKind.CLOSED; }
    | "open" { recordKind = RecordTypeDefinition.RecordKind.OPEN; } )?
   "{"
        (
          RecordField(recType)
          ( ","  RecordField(recType) )*
        )?
   "}"
   {
      if (recordKind == null) {
        recordKind = RecordTypeDefinition.RecordKind.OPEN;
      }
      recType.setRecordKind(recordKind);
      return recType;
   }
}

void RecordField(RecordTypeDefinition recType) throws ParseException:
{
        String fieldName;
        TypeExpression type = null;
        boolean nullable = false;
}
{
      <IDENTIFIER>
          {
         Token t = getToken(0);
         fieldName = t.toString();
        }
      ":"
      ( type =  TypeExpr() )
      ("?" { nullable = true; } )?
      {

         recType.addField(fieldName, type, nullable);
      }
}

TypeReferenceExpression TypeReference() throws ParseException:
{}
{
  <IDENTIFIER>
      {
      Token t = getToken(0);
      Identifier id;
      if (t.toString().equalsIgnoreCase("int")) {
          id = new Identifier("int64");
      } else {
          id = new Identifier(t.toString());
      }
          return new TypeReferenceExpression(id);
    }
}

OrderedListTypeDefinition OrderedListTypeDef() throws ParseException:
{
  TypeExpression type = null;
}
{
  "["
    ( type =  TypeExpr() )
  "]"
  {
    return new OrderedListTypeDefinition(type);
  }
}


UnorderedListTypeDefinition UnorderedListTypeDef() throws ParseException:
{
  TypeExpression type = null;
}
{
  "<"
    ( type =  TypeExpr() )
  ">"
  {
    return new UnorderedListTypeDefinition(type);
  }
}


FunctionDecl FunctionDeclaration() throws ParseException:
{
  FunctionDecl funcDecl;
  FunctionSignature signature;
  String functionName;
  int arity = 0;
  List<VarIdentifier> paramList = new ArrayList<VarIdentifier>();
  Expression funcBody;
  VarIdentifier var = null;
  createNewScope();
}
{

    <IDENTIFIER>
    {
      Token t = getToken(0);
      functionName = t.toString();
      if (functionName.equalsIgnoreCase("int")) {
          functionName = "int64";
      }
    }
    <LEFTPAREN> (<VARIABLE>
    {
      var = new VarIdentifier();
      var.setValue(getToken(0).toString());
      paramList.add(var);
      getCurrentScope().addNewVarSymbolToScope(var);
      arity++;
    }
    ("," <VARIABLE>
    {
      var = new VarIdentifier();
      var.setValue(getToken(0).toString());
      paramList.add(var);
      getCurrentScope().addNewVarSymbolToScope(var);
      arity++;
    })*)? <RIGHTPAREN> "{" funcBody = Expression() "}"

    {
      signature = new FunctionSignature(defaultDataverse, functionName, arity);
      getCurrentScope().addFunctionDescriptor(signature, false);
      funcDecl = new FunctionDecl(signature, paramList, funcBody);
      return funcDecl;
    }
}

Query Query()throws ParseException:
{
  Query query = new Query();
  Expression expr;
}
{
    expr = Expression()

    {
      query.setBody(expr);
      return query;
    }
}


Expression Expression():
{
  Expression expr = null;
  Expression exprP = null;
}
{
(

//OperatorExpr | IfThenElse | FLWOGRExpression | QuantifiedExpression
    expr = OperatorExpr()
    | expr = IfThenElse()
    | expr = FLWOGR()
    | expr = QuantifiedExpression()


)
    {
      return (exprP==null) ? expr : exprP;
    }
}


Expression OperatorExpr()throws ParseException:
{
  OperatorExpr op = null;
  Expression operand = null;
}
{
    operand = AndExpr()
    (

      "or"
      {
        if (op == null) {
          op = new OperatorExpr();
          op.addOperand(operand);
        op.setCurrentop(true);
        }
        Token t = getToken(0);
        try{
          op.addOperator(t.toString());
        } catch (Exception e){
          throw new ParseException(e.getMessage());
        }
    }

    operand = AndExpr()
    {
      op.addOperand(operand);
    }

    )*

    {
      return op==null? operand: op;
    }
}

Expression AndExpr()throws ParseException:
{
  OperatorExpr op = null;
  Expression operand = null;
}
{
    operand = RelExpr()
    (

      "and"
      {
        if (op == null) {
          op = new OperatorExpr();
          op.addOperand(operand);
        op.setCurrentop(true);
        }
        Token t = getToken(0);
        try{
          op.addOperator(t.toString());
        } catch (Exception e){
          throw new ParseException(e.getMessage());
        }
    }

    operand = RelExpr()
    {
      op.addOperand(operand);
    }

    )*

    {
      return op==null? operand: op;
    }
}


Expression RelExpr()throws ParseException:
{
  OperatorExpr op = null;
  Expression operand = null;
  boolean broadcast = false;
}
{
    operand = AddExpr()
    {
      if (operand instanceof VariableExpr) {
        String hint = getHint(token);
        if (hint != null && hint.equals(BROADCAST_JOIN_HINT)) {
          broadcast = true;
        }
      }
    }

    (
      LOOKAHEAD(2)( "<" | ">" | "<=" | ">=" | "=" | "!=" |"~=")
        {
          if (op == null) {
            op = new OperatorExpr();
            op.addOperand(operand, broadcast);
          op.setCurrentop(true);
          broadcast = false;
          }
          Token t = getToken(0);
          try{
            op.addOperator(t.toString());
          } catch (Exception e){
            throw new ParseException(e.getMessage());
          }
      }

       operand = AddExpr()
      {
         broadcast = false;
         if (operand instanceof VariableExpr) {
           String hint = getHint(token);
           if (hint != null && hint.equals(BROADCAST_JOIN_HINT)) {
             broadcast = true;
           }
         }
         op.addOperand(operand, broadcast);
      }
    )?

     {
       return op==null? operand: op;
     }
}

Expression AddExpr()throws ParseException:
{
  OperatorExpr op = null;
  Expression operand = null;
}
{
    operand = MultExpr()

    ( ("+" | "-")
      {
        if (op == null) {
          op = new OperatorExpr();
        op.addOperand(operand);
        op.setCurrentop(true);
        }
        Token t = getToken(0);
      try{
          ((OperatorExpr)op).addOperator(t.toString());
      } catch (Exception e){
          throw new ParseException(e.getMessage());
      }
    }

    operand = MultExpr()
    {
      op.addOperand(operand);
    }
    )*

    {
       return op==null? operand: op;
     }
}

Expression MultExpr()throws ParseException:
{
  OperatorExpr op = null;
  Expression operand = null;
}
{
    operand = UnionExpr()

    (( "*" | "/" | "%" | <CARET> | "idiv")
      {
        if (op == null) {
          op = new OperatorExpr();
        op.addOperand(operand);
        op.setCurrentop(true);
        }
        Token t = getToken(0);
        try{
          op.addOperator(t.toString());
        } catch (AsterixException e){
          throw new ParseException(e.getMessage());
        }
    }
    operand = UnionExpr()
    {
       op.addOperand(operand);
    }
    )*

     {
       return op==null?operand:op;
     }
}

Expression UnionExpr() throws ParseException:
{
    UnionExpr union = null;
    Expression operand1 = null;
    Expression operand2 = null;
}
{
   operand1 = UnaryExpr()
   ("union"
       (operand2 = UnaryExpr()) {
          if (union == null) {
             union = new UnionExpr();
             union.addExpr(operand1);
          }
          union.addExpr(operand2);
       } )*
   {
     return (union == null)? operand1: union;
   }
}

Expression UnaryExpr() throws ParseException:
{
    UnaryExpr uexpr = null;
    Expression expr = null;
}
{
    ( ("+"|"-")
    {
          uexpr = new UnaryExpr();
          try{
            uexpr.setExprType(token.image);
          } catch (AsterixException e){
            throw new ParseException(e.getMessage());
          }
    }
    )?

    expr = ValueExpr()
    {
        if(uexpr!=null){
            ((UnaryExpr)uexpr).setExpr(expr);
            return uexpr;
        }
        else{
            return expr;
        }
    }
}

Expression ValueExpr() throws ParseException:
{
  Expression expr;
}
{
  expr = FieldOrIndexAccessor()
  {
    return expr;
  }
}


Expression FieldOrIndexAccessor()throws ParseException:
{
  Expression expr = null;
  Identifier ident = null;
  AbstractAccessor fa = null;
  Expression indexExpr = null;

}
{
    ( expr = PrimaryExpr()

    )


    (
    (
          ident = Field()
    {
          if(fa == null)
              fa = new FieldAccessor(expr, ident);
          else
              fa = new FieldAccessor(fa, ident);
    }
    )
    | (
        indexExpr = Index()
        {
          if(fa == null)
            fa = new IndexAccessor(expr, indexExpr);
          else
            fa = new IndexAccessor(fa, indexExpr);
        }
    )
    )*


      {
       return fa==null?expr:fa;
     }
}

Identifier Field() throws ParseException:
{
  Identifier ident = null;

}
{
  "." < IDENTIFIER >
      {

      ident = new Identifier();
    ident.setValue(getToken(0).toString());

      return ident;
    }
}

Expression Index() throws ParseException:
{
    Expression expr = null;
}
{
  "[" ( expr = Expression()
    {
        if(expr.getKind() == Expression.Kind.LITERAL_EXPRESSION)
        {
            Literal lit = ((LiteralExpr)expr).getValue();
            if(lit.getLiteralType() != Literal.Type.INTEGER &&
               lit.getLiteralType() != Literal.Type.LONG) {
                throw new ParseException("Index should be an INTEGER");
            }
        }
    }

      | "?" // ANY

      )

   "]"
    {
      return expr;
    }
}


Expression PrimaryExpr()throws ParseException:
{
  Expression expr = null;
}
{
  //Literal | VariableRef | ListConstructor | RecordConstructor | FunctionCallExpr | ParenthesizedExpression
    (
      expr =Literal()
       | expr = FunctionCallExpr()
       | expr =VariableRef()

    {
      if(((VariableExpr)expr).getIsNewVar() == true)
          throw new ParseException("can't find variable " + ((VariableExpr)expr).getVar());
    }
           | expr = ListConstructor()
       | expr = RecordConstructor()
       | expr = ParenthesizedExpression()
       | expr = MetaVariableRef()
    )
     {
       return expr;
     }
}

Expression Literal() throws ParseException:
{

  LiteralExpr lit = new LiteralExpr();
  Token t;
}
{
(
      <STRING_LITERAL>
    {
      t= getToken(0);
      lit.setValue( new StringLiteral(removeQuotesAndEscapes(t.image)));
    }

      | <INTEGER_LITERAL>
    {
      t= getToken(0);
      try {
          lit.setValue(new IntegerLiteral(new Integer(t.image)));
      } catch(NumberFormatException ex) {
          lit.setValue(new LongIntegerLiteral(new Long(t.image)));
      }
    }
     | < FLOAT_LITERAL >
    {
      t= getToken(0);
      lit.setValue(new FloatLiteral(new Float(t.image)));
    }
     | < DOUBLE_LITERAL >
    {
      t= getToken(0);
      lit.setValue(new DoubleLiteral(new Double(t.image)));
    }
      | <NULL>
    {
      t= getToken(0);
      lit.setValue(NullLiteral.INSTANCE);
    }
        | <TRUE>
    {
      t= getToken(0);
      lit.setValue(TrueLiteral.INSTANCE);
    }
        | <FALSE>
    {
      t= getToken(0);
      lit.setValue(FalseLiteral.INSTANCE);
    }
)
    {
      return lit;
    }
}


VariableExpr VariableRef() throws ParseException:
{
    VariableExpr varExp = new VariableExpr();
    VarIdentifier var = new VarIdentifier();
    Token t;
}
{
      <VARIABLE>
    {
     t = getToken(0);//get current token
     String varName = t.toString();
     Identifier ident = lookupSymbol(varName);
     if (isInForbiddenScopes(varName)) {
       throw new ParseException("Inside limit clauses, it is disallowed to reference a variable having the same name as any variable bound in the same scope as the limit clause.");
     }
     if(ident != null) { // exist such ident
       varExp.setIsNewVar(false);
       varExp.setVar((VarIdentifier)ident);
     } else {
       varExp.setVar(var);
     }
     var.setValue(t.toString());
     return varExp;
    }
}


VariableExpr Variable() throws ParseException:
{
    VariableExpr varExp = new VariableExpr();
    VarIdentifier var = new VarIdentifier();
    Token t;
}
{
      <VARIABLE>
    {
     t = getToken(0);//get current token
     Identifier ident = lookupSymbol(t.toString());
     if(ident != null) { // exist such ident
       varExp.setIsNewVar(false);
     }
     varExp.setVar(var);
     var.setValue(t.toString());
     return varExp;
    }
}

MetaVariableExpr MetaVariableRef() throws ParseException:
{
    MetaVariableExpr metaVarExp = new MetaVariableExpr();
    VarIdentifier var = new VarIdentifier();
    Token t;
}
{
      <METAVARIABLE>
    {
     t = getToken(0);//get current token
     metaVarExp.setVar(var);
     var.setValue(t.toString());
     return metaVarExp;
    }
}

Expression ListConstructor() throws ParseException:
{
    Expression expr = null;
}
{
    (
        expr = OrderedListConstructor() | expr = UnorderedListConstructor()
    )

    {
      return expr;
    }
}


ListConstructor OrderedListConstructor() throws ParseException:
{
      ListConstructor expr = new ListConstructor();
      Expression tmp = null;
      List<Expression> exprList = new ArrayList<Expression>();
      expr.setType(ListConstructor.Type.ORDERED_LIST_CONSTRUCTOR);
}
{

    "["
        ( tmp = Expression()
            {
              exprList.add(tmp);
            }

            ("," tmp = Expression() { exprList.add(tmp);  })*
        )?

    "]"

    {
      expr.setExprList(exprList);
      return expr;
    }
}

ListConstructor UnorderedListConstructor() throws ParseException:
{
      ListConstructor expr = new ListConstructor();
      Expression tmp = null;
      List<Expression> exprList = new ArrayList<Expression>();
      expr.setType(ListConstructor.Type.UNORDERED_LIST_CONSTRUCTOR);
}
{

    "{{" ( tmp = Expression()
    {
      exprList.add(tmp);
    }
    ("," tmp = Expression() { exprList.add(tmp);  })*)? "}}"
    {
      expr.setExprList(exprList);
      return expr;
    }
}

RecordConstructor RecordConstructor() throws ParseException:
{
      RecordConstructor expr = new RecordConstructor();
      FieldBinding tmp = null;
      List<FieldBinding> fbList = new ArrayList<FieldBinding>();
}
{
    "{" (tmp = FieldBinding()
    {
      fbList.add(tmp);
    }
    ("," tmp = FieldBinding() { fbList.add(tmp);  })*)? "}"
    {
      expr.setFbList(fbList);
      return expr;
    }
}

FieldBinding FieldBinding() throws ParseException:
{
    FieldBinding fb = new FieldBinding();
    Expression left, right;
}
{
    left = Expression() ":" right = Expression()
    {
      fb.setLeftExpr(left);
      fb.setRightExpr(right);
      return fb;
    }
}

Expression FunctionCallExpr() throws ParseException:
{
  CallExpr callExpr;
  List<Expression> argList = new ArrayList<Expression>();
  Expression tmp;
  int arity = 0;
  String funcName;
  String dataverse;
  String hint=null;
  String id1=null;
  String id2=null;
}
{
    ( <IDENTIFIER> { dataverse = defaultDataverse; funcName = token.image;}
     ("." <IDENTIFIER> { dataverse = funcName; funcName = token.image;})?
     |
     <DATASET> {dataverse = MetadataConstants.METADATA_DATAVERSE_NAME; funcName = getToken(0).toString();}
    )
    {
       hint=getHint(token);
    }
     <LEFTPAREN> (tmp = Expression()
     {
       argList.add(tmp);
       arity ++;
     } ("," tmp = Expression() { argList.add(tmp); arity++; })*)? <RIGHTPAREN>

     {
       FunctionSignature signature = lookupFunctionSignature(dataverse, funcName.toString(), arity);
             if(signature == null)
             {
                signature = new FunctionSignature(dataverse, funcName.toString(), arity);
             }
       callExpr = new CallExpr(signature,argList);
       if (hint != null && hint.startsWith(INDEXED_NESTED_LOOP_JOIN_HINT)) {
          callExpr.addHint(IndexedNLJoinExpressionAnnotation.INSTANCE);
        }
       return callExpr;
     }
}


Expression ParenthesizedExpression() throws ParseException:
{
  Expression expr;
}
{
    <LEFTPAREN> expr = Expression() <RIGHTPAREN>
    {
      return expr;
    }
}

Expression IfThenElse() throws ParseException:
{
  Expression condExpr;
  Expression thenExpr;
  Expression elseExpr;
  IfExpr ifExpr = new IfExpr();
}
{
    "if" <LEFTPAREN> condExpr = Expression() <RIGHTPAREN> "then" thenExpr = Expression() "else" elseExpr = Expression()

    {
      ifExpr.setCondExpr(condExpr);
      ifExpr.setThenExpr(thenExpr);
      ifExpr.setElseExpr(elseExpr);
      return ifExpr;
    }
}

Expression  FLWOGR() throws ParseException:
{
    FLWOGRExpression flworg = new FLWOGRExpression();
    List<Clause> clauseList = new ArrayList<Clause>();
    Expression returnExpr;
    Clause tmp;
    createNewScope();
}
{
     (tmp = ForClause()  {clauseList.add(tmp);} | tmp = LetClause() {clauseList.add(tmp);} | tmp = MetaVariableClause() {clauseList.add(tmp);})
      (tmp = Clause() {clauseList.add(tmp);})* "return" returnExpr = Expression()

     {
       flworg.setClauseList(clauseList);
       flworg.setReturnExpr(returnExpr);
       removeCurrentScope();
       return flworg;
     }
}

List<Clause> Clauses() throws ParseException:
{
    List<Clause> clauses = new ArrayList<Clause>();
    Clause c = null;
}
{
    (
        (
            c = Clause() {
                clauses.add(c);
            }
        )*
    )
    {
        return clauses;
    }
}

Clause Clause() throws ParseException :
{
  Clause clause;
}
{
    (
         clause = ForClause()
       | clause = LetClause()
       | clause = WhereClause()
       | clause = OrderbyClause()
       | clause = GroupClause()
       | clause = LimitClause()
       | clause = DistinctClause()
       | clause = MetaVariableClause()
       | clause = JoinClause()
    )
    {
      return clause;
    }
}

Clause MetaVariableClause() throws ParseException :
{
    MetaVariableClause mc = new MetaVariableClause();
    VarIdentifier var = new VarIdentifier();
    Token t;
}
{
    <METAVARIABLECLAUSE>
    {
      t = getToken(0);
      mc.setVar(var);
      var.setValue(t.toString());
      return mc;
    }
}

Clause JoinClause() throws ParseException :
{
    Expression whereExpr;
    List<Clause> leftClauses, rightClauses;
    JoinClause.JoinKind kind = JoinClause.JoinKind.INNER;
}
{
    ("join" | "loj" { kind = JoinClause.JoinKind.LEFT_OUTER; } )
      <LEFTPAREN> <LEFTPAREN> leftClauses = Clauses() <RIGHTPAREN> ","
      <LEFTPAREN> rightClauses = Clauses() <RIGHTPAREN> ","
      whereExpr = Expression() <RIGHTPAREN>
    {
      JoinClause jc = new JoinClause(kind);
      jc.setLeftClauses(leftClauses);
      jc.setRightClauses(rightClauses);
      jc.setWhereExpr(whereExpr);
      return jc;
    }
}

Clause ForClause()throws ParseException :
{
    ForClause fc = new ForClause();
    VariableExpr varExp;
    VariableExpr varPos = null;
    Expression inExp;
    extendCurrentScope();
}
{
    "for" varExp = Variable()
    {
         getCurrentScope().addNewVarSymbolToScope(varExp.getVar());
    }
    ("at" varPos = Variable()
      {
         getCurrentScope().addNewVarSymbolToScope(varPos.getVar());
      }
     )?
      "in" ( inExp = Expression() )
    {
      fc.setVarExpr(varExp);
      fc.setInExpr(inExp);
      if (varPos != null) {
        fc.setPosExpr(varPos);
      }
      return fc;
    }
}

Clause LetClause() throws ParseException:
{
    LetClause lc = new LetClause();
    VariableExpr varExp;
    Expression beExp;
    extendCurrentScope();
}
{
    "let" varExp = Variable() ":=" beExp = Expression()
    {
      getCurrentScope().addNewVarSymbolToScope(varExp.getVar());
      lc.setVarExpr(varExp);
      lc.setBindingExpr(beExp);
      return lc;
    }
}

Clause WhereClause()throws ParseException :
{
  WhereClause wc = new WhereClause();
  Expression whereExpr;
}
{
    "where" whereExpr = Expression()
    {
      wc.setWhereExpr(whereExpr);
      return wc;
    }
}

Clause OrderbyClause()throws ParseException :
{
  OrderbyClause oc = new OrderbyClause();
  Expression orderbyExpr;
  List<Expression> orderbyList = new ArrayList<Expression>();
  List<OrderbyClause.OrderModifier> modifierList = new ArrayList<OrderbyClause.OrderModifier >();
  int numOfOrderby = 0;
}
{
  (
    "order"
      {
         String hint = getHint(token);
         if (hint != null && hint.startsWith(INMEMORY_HINT)) {
           String splits[] = hint.split(" +");
           int numFrames = Integer.parseInt(splits[1]);
           int numTuples = Integer.parseInt(splits[2]);
           oc.setNumFrames(numFrames);
           oc.setNumTuples(numTuples);
         }
      }
    "by" orderbyExpr = Expression()
    {
      orderbyList.add(orderbyExpr);
      OrderbyClause.OrderModifier modif = OrderbyClause.OrderModifier.ASC;
    }
    ( ("asc" { modif = OrderbyClause.OrderModifier.ASC; })
    | ("desc" { modif = OrderbyClause.OrderModifier.DESC; }))?
    {
      modifierList.add(modif);
    }

    ("," orderbyExpr = Expression()
    {
      orderbyList.add(orderbyExpr);
      modif = OrderbyClause.OrderModifier.ASC;
    }
    ( ("asc" { modif = OrderbyClause.OrderModifier.ASC; })
    | ("desc" { modif = OrderbyClause.OrderModifier.DESC; }))?
    {
      modifierList.add(modif);
    }
    )*
)
    {
      oc.setModifierList(modifierList);
      oc.setOrderbyList(orderbyList);
      return oc;
    }
}
Clause GroupClause()throws ParseException :
{
      GroupbyClause gbc = new GroupbyClause();
      // GbyVariableExpressionPair pair = new GbyVariableExpressionPair();
     List<GbyVariableExpressionPair> vePairList = new ArrayList<GbyVariableExpressionPair>();
    List<GbyVariableExpressionPair> decorPairList = new ArrayList<GbyVariableExpressionPair>();
    List<VariableExpr> withVarList= new ArrayList<VariableExpr>();
    VariableExpr var = null;
    VariableExpr withVar = null;
    Expression expr = null;
    VariableExpr decorVar = null;
    Expression decorExpr = null;
}
{
      {
        Scope newScope = extendCurrentScopeNoPush(true);
        // extendCurrentScope(true);
      }
    "group"
      {
         String hint = getHint(token);
         if (hint != null && hint.equals(HASH_GROUP_BY_HINT)) {
           gbc.setHashGroupByHint(true);
         }
      }
    "by" (LOOKAHEAD(2)  var = Variable()
    {
      newScope.addNewVarSymbolToScope(var.getVar());
    } ":=")?
    expr = Expression()
       {
         GbyVariableExpressionPair pair1 = new GbyVariableExpressionPair(var, expr);
         vePairList.add(pair1);
       }
    ("," ( LOOKAHEAD(2) var = Variable()
    {
      newScope.addNewVarSymbolToScope(var.getVar());
    } ":=")?
        expr = Expression()
         {
           GbyVariableExpressionPair pair2 = new GbyVariableExpressionPair(var, expr);
           vePairList.add(pair2);
         }
        )*
    ("decor" decorVar = Variable() ":=" decorExpr = Expression()
       {
         newScope.addNewVarSymbolToScope(decorVar.getVar());
         GbyVariableExpressionPair pair3 = new GbyVariableExpressionPair(decorVar, decorExpr);
         decorPairList.add(pair3);
       }
      ("," "decor" decorVar = Variable() ":=" decorExpr = Expression()
           {
             newScope.addNewVarSymbolToScope(decorVar.getVar());
             GbyVariableExpressionPair pair4 = new GbyVariableExpressionPair(decorVar, decorExpr);
             decorPairList.add(pair4);
           }
       )*
    )?
    "with" withVar = VariableRef()
    {
      if(withVar.getIsNewVar()==true)
          throw new ParseException("can't find variable " + withVar.getVar());
      withVarList.add(withVar);
      newScope.addNewVarSymbolToScope(withVar.getVar());
    }
    ("," withVar = VariableRef()
    {
      if(withVar.getIsNewVar()==true)
          throw new ParseException("can't find variable " + withVar.getVar());
      withVarList.add(withVar);
      newScope.addNewVarSymbolToScope(withVar.getVar());
    })*
    {
      gbc.setGbyPairList(vePairList);
      gbc.setDecorPairList(decorPairList);
      gbc.setWithVarList(withVarList);
      replaceCurrentScope(newScope);
      return gbc;
    }
}


LimitClause LimitClause() throws ParseException:
{
    LimitClause lc = new LimitClause();
    Expression expr;
    pushForbiddenScope(getCurrentScope());
}
{
    "limit" expr = Expression()    { lc.setLimitExpr(expr);    }
    ("offset" expr = Expression() { lc.setOffset(expr);    })?

  {
    popForbiddenScope();
    return lc;
  }
}

DistinctClause DistinctClause() throws ParseException:
{
  List<Expression> exprs = new ArrayList<Expression>();
  Expression expr;
}
{
  "distinct" "by" expr = Expression()
  {
    exprs.add(expr);
  }
  ("," expr = Expression()
      {
          exprs.add(expr);
      }
  )*
  {
      return new DistinctClause(exprs);
  }
}


QuantifiedExpression QuantifiedExpression()throws ParseException:
{
  QuantifiedExpression qc = new QuantifiedExpression();
  List<QuantifiedPair> quantifiedList = new ArrayList<QuantifiedPair>();
  Expression satisfiesExpr;
  VariableExpr var;
  Expression inExpr;
  QuantifiedPair pair;
}
{
  {
    createNewScope();
  }

   (      ("some"  {  qc.setQuantifier(QuantifiedExpression.Quantifier.SOME);    })
        | ("every" {  qc.setQuantifier(QuantifiedExpression.Quantifier.EVERY);    }))
    var = Variable() "in" inExpr = Expression()
    {
      pair = new QuantifiedPair(var, inExpr);
      getCurrentScope().addNewVarSymbolToScope(var.getVar());
      quantifiedList.add(pair);
    }
    (
    "," var = Variable() "in" inExpr = Expression()
    {
      pair = new QuantifiedPair(var, inExpr);
      getCurrentScope().addNewVarSymbolToScope(var.getVar());
      quantifiedList.add(pair);
    }
    )*
     "satisfies" satisfiesExpr = Expression()
     {
       qc.setSatisfiesExpr(satisfiesExpr);
       qc.setQuantifiedList(quantifiedList);
       removeCurrentScope();
       return qc;
     }
}

TOKEN_MGR_DECLS:
{
        public int commentDepth = 0;
}

<DEFAULT>
TOKEN :
{
   <CARET : "^"  >
}

<DEFAULT>
TOKEN :
{
   <DATASET : "dataset"  >
}

<DEFAULT>
TOKEN :
{
   <LEFTPAREN : "("  >
}

<DEFAULT>
TOKEN :
{
   <RIGHTPAREN : ")"  >
}


<DEFAULT>
TOKEN :
{
    <INTEGER_LITERAL : (<DIGIT>)+ >
}


<DEFAULT>
TOKEN :
{
    <NULL : "null">
}

<DEFAULT>
TOKEN :
{
    <TRUE : "true">
}

<DEFAULT>
TOKEN :
{
    <FALSE : "false">
}

<DEFAULT>
TOKEN :
{
    <#DIGIT : ["0" - "9"]>
}


TOKEN:
{
  < DOUBLE_LITERAL: <INTEGER>
        | <INTEGER> ( "." <INTEGER> )?
        | "." <INTEGER>
  >
  |
  < FLOAT_LITERAL: <INTEGER> ( "f" | "F" )
        | <INTEGER> ( "." <INTEGER> ( "f" | "F" ) )?
        | "." <INTEGER> ( "f" | "F" )
  >
  |
  <INTEGER : (<DIGIT>)+ >
}

<DEFAULT>
TOKEN :
{
    <#LETTER : ["A" - "Z", "a" - "z"]>
}

<DEFAULT>
TOKEN :
{
    <SPECIALCHARS : ["$", "_", "-"]  >
}

<DEFAULT>
TOKEN :
{
    <STRING_LITERAL : ("\"" (<EscapeQuot> | ~["\""])* "\"") | ("\'"(<EscapeApos> | ~["\'"])* "\'")>
    |
    < #EscapeQuot: "\\\"" >
    |
    < #EscapeApos: "\\\'" >
}

<DEFAULT>
TOKEN :
{
    <IDENTIFIER : (<LETTER>)+ (<LETTER> | <DIGIT> | <SPECIALCHARS>)*>
}

<DEFAULT>
TOKEN :
{
    <VARIABLE : "$" <IDENTIFIER> >
}

<DEFAULT>
TOKEN :
{
    <METAVARIABLECLAUSE : "#" <IDENTIFIER> >
}

<DEFAULT>
TOKEN :
{
    <METAVARIABLE : "$$" <IDENTIFIER> >
}

SKIP:
{
    " "
|   "\t"
|   "\r"
|   "\n"
}

SKIP:
{
    <"//" (~["\n"])* "\n">
}

SKIP:
{
    <"//" (~["\n","\r"])* ("\n"|"\r"|"\r\n")?>
}


SKIP:
{
        <"/*"> {commentDepth=1;}: INSIDE_COMMENT
}

<INSIDE_COMMENT>
SPECIAL_TOKEN:
{
       <"+"(" ")*(~["/","*"])*>
}

<INSIDE_COMMENT>
SKIP:
{
        <"/*"> {commentDepth++;}
}

<INSIDE_COMMENT>
SKIP:
{
        <"*/"> {commentDepth--; if (commentDepth == 0) SwitchTo(DEFAULT);}
|       <~[]>
}