cchecker

/*
* JContextChecker.java
*
* Created on March 12, 2005, 12:16 PM
*/

package compiler;

import java.util.* ;
import java.io.* ;

/**
*
* @author Administrator
*/
public class JContextChecker implements ASTVisitor{
    public JTable symtable ;
    public String temporary_return_type ;//Just to Store the return type of Methods
                                         //Becomes null when leaving the scope. Line Number: 142
                                         //To be used to check the return type of the function
                                         //in ReturnCommand
    public boolean return_statement_availability ;//Again to indiacte whether a return statement is available in the current scope

    /** Creates a new instance of JContextChecker */
    public JContextChecker() {
        symtable = new JTable();
        temporary_return_type = null ;
        return_statement_availability = false ;
    }

    public void check(AST ast){
        ast.visit(this,null);
    }

    public void error(String message){
        System.out.println("Error: "+message) ;
        System.exit(0);
    }

    public Object visitCompilationUnit(CompilationUnit p,Object arg){
        System.out.println("In Visit Compilation Unit");
        p.cd.visit(this,null);
        return null ;
    }

    public Object visitClassDeclaration(ClassDeclaration p,Object arg){
        System.out.println("In Visit Class Declaration");
        boolean ret = symtable.insert(p.classname.terminal,p.publicdec.terminal,false,"class");
        if(ret == false){
            error("Cant enter the Class NAme");
        }else{
            System.out.println("Successful");
        }
        symtable.enterScope();
        if(p.classbody != null){
            p.classbody.visit(this,null);
        }
        return null ;
    }

    public Object visitClassBody(ClassBody p,Object arg){
        System.out.println("In Visit Class Body");
        if(p.ds != null){
            p.ds.visit(this,null);
        }
        return null ;
    }

    public Object visitVariableDeclarations(VariableDeclarations p,Object arg){
        System.out.println("In Visit Variable Declarations");
        String scopemodifier = null ;
        if(p.modifier != null){
            scopemodifier = p.modifier.str ;
        }
        boolean st = false ;
        if(p.staticvariable != null){
            if(p.staticvariable.modifier.equals("static")){
                st = true ;
            }else{
                st = false ;
            }
        }
        String tp = null ;
        if(p.type.ptype == true){
            tp = p.type.primitivetype.terminal;
        }else{
            tp = p.type.name.name;
        }
        if(p.type.ptype == true){
            if(tp.equals("void")){
                error("Void type Variables are not allowed to be declared");
            }
        }

        boolean ret = symtable.insert(p.variablename.terminal,scopemodifier,st,tp);
        if(ret == false ){
            error("Variable Insertion Error");
        }
        return tp ;
    }

    public Object visitFunctionDeclarations(FunctionDeclarations p,Object arg){
        System.out.println("In Visit Function Declarations");
        String md = p.md.str ;
        boolean st = false ;
        if(p.staticfunction != null){
            if(p.staticfunction.modifier.equals("static")){
                st = true ;
            }else{
                st = false ;
            }
        }
        String tp = null ;
        if(p.type.ptype == true){
            tp = p.type.primitivetype.terminal;
        }else{
            tp = p.type.name.name;
        }
        LinkedList plist = null ;

   if (p.parameterlist != null){
        if (p.parameterlist instanceof SequenceDeclarations)
        {
       plist = (LinkedList) p.parameterlist.visit(this, null) ;
        }
        else
        {
       plist = new LinkedList() ;
       String temp = (String) p.parameterlist.visit(this, null) ;
       plist.addFirst(temp) ;
        }
   }
   else
   {
        plist = new LinkedList() ;
   }
        temporary_return_type = tp ;
   boolean ret = symtable.insert(p.functionname.terminal, p.md.str, st, tp,plist, p.declaration_type) ;
        symtable.enterScope() ;
   if (ret == false )
   {
        error("Method could not be inserted") ;
   }
   p.block.visit(this,null);
   symtable.leaveScope() ;
        temporary_return_type = null ;
        if(tp.equals("void")==false && return_statement_availability==false){
            error("No Return Statement");
        }
        return_statement_availability = false ;
   return null ;
    }

    public Object visitBlock(Block p, Object arg) {
        System.out.println("In Visit Block");
        if(p.dec != null){
            p.dec.visit(this,null);
        }
        if(p.cmd != null){
            p.cmd.visit(this,null);
        }
        return null ;
     }

    public Object visitSequenceDeclarations(SequenceDeclarations p,Object arg){
        System.out.println("In Visit SequenceDeclarations") ;
   LinkedList plist = null ;
   if (p.declarationsone instanceof SequenceDeclarations){
            System.out.println("Calling Sequence Declarations's Visit") ;
        plist = (LinkedList) p.declarationsone.visit(this , null) ;
        System.out.println("Back in Sequence Declaration's Visit"+plist) ;

        String t2 = (String) p.declarationstwo.visit(this , null) ;
        plist.addLast(t2) ;   // plist should not be null.
   }
   else
   {
        String t1 = (String) p.declarationsone.visit(this , null) ;
        String t2 = (String) p.declarationstwo.visit(this , null) ;
        // This is the first expr in the sequence.
        plist = new LinkedList() ;
        plist.addFirst(t1) ;
        plist.addLast(t2) ;
        System.out.println("Return List") ;
   }
   return plist ;
    }

   public Object visitAssignmentCommand(AssignmentCommand p, Object arg) {
       System.out.println("In Visit Assignment Command ") ;
       String type1 = (String) p.tan.visit(this,null) ;
       String type2 = (String) p.exp.visit(this, null) ;
       System.out.println("Type1 = "+type1+" t2= "+type2) ;

   if (type1 == null || type2 == null || !type1.equals(type2) ){
            if (type1 == null){
                error("Error on the type of Assignment Command(left side)") ;
        }else{
       error("Error on the type of Assignment Command(right side)") ;
        }
   }
   return null ;
    }

   public Object visitMethodCallCommand(MethodCallCommand p,Object arg){
       System.out.println("In Visit Method Call Command");
       String retType = null ;

        //First Part Must Check for the Return Type
       System.out.println("Hiii"+p.tan.name.name);
       methodSymObject obj = (methodSymObject)symtable.lookup(p.tan.name.name);
       System.out.println("CC"+p.tan.name.name+" "+obj);
       if(obj!=null){
           if(!obj.type_of_object.equals("function")){
               error("No Such Function");
           }
           retType = (String)obj.type ;
        }else{//Object is null. No such Function in the current class.Search in the API's
            StringTokenizer str = new StringTokenizer(p.tan.name.name,".");
            obj = (methodSymObject)symtable.lookup(str.nextToken());
            if(obj==null){//No such Object exisits
                error("Undefined Variable Here");
            }else{
                String classname = obj.type ;
                JParserUtil jps = new JParserUtil();
                if(!jps.isClassLoadAvail(classname)){//No such class
                    error("No Such Class");
                }
                String functionname = str.nextToken();
                Class temp = jps.isMethodFound(classname,functionname);

                if(temp!=null){
                    if(jps.isPublicMethod(classname,functionname)==false){
                        error("The Function is not a Public");
                    }
                    retType = temp.toString();
                    //Second part is to check for parametertypes
                    LinkedList type2 = new LinkedList();

                    if(p.exp != null){
                        type2 = (LinkedList)p.exp.visit(this,null);
                    }

                    LinkedList params = (LinkedList)jps.getParams(classname,functionname);

                    if(!params.equals(type2)){
                        error("Type Mismatch in Function Call");
                    }
                }else{
                    error("No such Function Exists");
                }
            }
        }
        return retType ;
   }

    public Object visitBinaryOpExpression(BinaryOpExpression p, Object arg) {
        System.out.println("In Visit BinaryOp Expression ") ;
   String t1 = (String) p.expressionone.visit(this , null) ;
   String t2 = (String) p.expressiontwo.visit(this , null) ;
   String op = p.operator.terminal ;
   String type = null ;

   if ( t1.equals(t2)){
            if (op.equals("+") && t1.equals("int")
                || op.equals("-") && t1.equals("int")
                || op.equals("*") && t1.equals("int")
                || op.equals("/") && t1.equals("int")
                || op.equals("|") && t1.equals("boolean")
                || op.equals("&") && t1.equals("boolean")){
                    type = t1 ;
            }else
                if ((op.equals("==") || op.equals("!=") || op.equals("&&") || op.equals("||")) &&
            (t1.equals("int") || t1.equals("boolean"))){
                        type = "boolean" ;
                }else
                    if ((op.equals("<") || op.equals("<=") || op.equals(">") || op.equals(">=")) &&
                         t1.equals("int")){
                             type ="boolean" ;
                    }else{
                        error("Type Matching Problem") ;
                    }
        }else{
        error("Type Mismatch") ;
   }
   return type ;
    }

    public Object visitIfElseCommand(IfElseCommand p, Object arg) {
        System.out.println("In Visit IfElse Command ") ;
        String t1 = (String)p.expression.visit(this, null) ;
   if (!t1.equals("boolean")){
        error("Return Value of the IfElse Command must be boolean") ;
   }
   if (p.command != null){
        p.command.visit(this, null) ;
   }
   if (p.ecommand != null){
        p.ecommand.visit(this, null) ;
   }
   return null ;
    }

    public Object visitJustThis(JustThis p, Object arg) {
        return (String)symtable.classname ;
    }

    public Object visitClassInstanceCreationExpression(ClassInstanceCreationExpression p, Object arg) {
        System.out.println("In Visit Class Instance Creation Expression");
        String retType = p.name.name ;


        LinkedList type2 = new LinkedList();
        if(p.expression != null){
            try{
                type2 = (LinkedList)p.expression.visit(this,null);
            }catch(Exception e){
                String temp = (String)p.expression.visit(this,null);
                type2.addLast(temp);
            }
        }

        StringTokenizer str = new StringTokenizer(p.name.name,".");
        String temp = null ;
        for(int i=0 ; i<str.countTokens()-1;i++)
            temp+=str.nextToken();
        String classname = str.nextToken();

        if(!classname.equals(symtable.classname)){
            JParserUtil jpu = new JParserUtil();
            if(!jpu.isClassLoadAvail(retType)){
                error("That Particular Class is not available");
            }
            //System.out.println("Package : "+p.name.name+" ClassName: "+classname+" Type2: "+type2);
            if(!jpu.getConstructorParams(p.name.name,classname,type2)){
                error("Type Mismatch in Class Instance Creation Expression");
            }
            return retType ;
        }else{
            methodSymObject obj = (methodSymObject)symtable.lookup(classname);
            LinkedList params = obj.params ;
            if(!type2.equals(params)){
                error("Type Mismatch in Constructor");
            }
            return retType ;
        }
    }

    public Object visitMethodCallExpression(MethodCallExpression p, Object arg) {
        System.out.println("In Visit Method Call Expression");
        String retType = null ;

        //First Part Must Check for the Return Type
        varSymObject obj = (varSymObject)symtable.lookup(p.tan.name.name);
        if(obj!=null){
            if(!obj.type_of_object.equals("function")){
                error("No Such Function");
            }
            retType = (String)obj.type ;
        }else{//Object is null. No such Function in the current class.Search in the API's
            StringTokenizer str = new StringTokenizer(p.tan.name.name,".");
            obj = (varSymObject)symtable.lookup(str.nextToken());
            if(obj==null){//No such Object exisits
                error("Undefined Variable Here");
            }else{
                String classname = obj.type ;
                JParserUtil jps = new JParserUtil();
                if(!jps.isClassLoadAvail(classname)){//No such class
                    error("No Such Class");
                }
                String functionname = str.nextToken();
                Class temp = jps.isMethodFound(classname,functionname);

                if(temp!=null){
                    if(jps.isPublicMethod(classname,functionname)==false){
                        error("The Function is not a Public");
                    }
                    retType = temp.toString();
                    //Second part is to check for parametertypes
                    LinkedList type2 = new LinkedList();

                    if(p.exp != null){
                        try{
                            type2 = (LinkedList)p.exp.visit(this,null);
                        }catch(Exception e){
                            String tmp = (String)p.exp.visit(this,null);
                            type2.addLast(tmp);
                        }
                    }

                    LinkedList params = (LinkedList)jps.getParams(classname,functionname);

                    if(!params.equals(type2)){
                        error("Type Mismatch in Function Call");
                    }
                }else{
                    error("No such Function Exists");
                }
            }
        }
        return retType ;
    }

    public Object visitReturnCommand(ReturnCommand p, Object arg) {
        System.out.println("In Visit Return Command ") ;
        return_statement_availability = true ;
        if(p.expression != null){
            String returntype =(String) p.expression.visit(this,null);
            if(!returntype.equals(temporary_return_type)){
                error("Return Type of the function does not match with return expression");
            }
        }else{
            if(!temporary_return_type.equals("void")){
                error("Return Type of the function does not match with return expression");
            }
        }
   return null ;
    }

    public Object visitSequenceCommand(SequenceCommand p, Object arg) {
        System.out.println("In Visit Sequence Command ") ;
   p.commandone.visit(this, null) ;
        if(p.commandtwo != null)
            p.commandtwo.visit(this, null) ;
   return null ;
    }

    public Object visitSequenceExpression(SequenceExpression p, Object arg) {
        System.out.println("In Sequence Expression") ;
   LinkedList plist = null ;
   if (p.expressionone instanceof SequenceExpression){
        plist = (LinkedList) p.expressionone.visit(this , null) ;
            if(p.expressiontwo != null){
                String t2 = (String) p.expressiontwo.visit(this , null) ;
                plist.addLast(t2) ;   // plist should not be null.
            }
   }
   else{
            String t1 = (String) p.expressionone.visit(this , null) ;
            // This is the first expr in the sequence.
            plist = new LinkedList() ;
        plist.addFirst(t1) ;
            if(p.expressiontwo != null){
                String t2 = (String) p.expressiontwo.visit(this , null) ;
                plist.addLast(t2) ;
            }
   }
   return plist ;
    }

    public Object visitThisAndNameExpression(ThisAndNameExpression p, Object arg) {
        System.out.println("In Visit This And Name Expression");
        return p.tan.visit(this,null);
    }

    public Object visitSimplePWLExpression(SimplePWLExpression p, Object arg) {
        System.out.println("In Visit Simple PWL Expression");
        return (String)p.exp.visit(this,null) ;
    }

    public Object visitThisAndName(ThisAndName p, Object arg) {

            System.out.println("In Visit This And Name");
            String retType = null ;
            varSymObject obj = (varSymObject)symtable.lookup(p.name.name);
            if(obj!=null){

                if(!obj.type_of_object.equals("variable")){
                    error("Function Cannot be Assigned any Value");
                }
                //System.out.println("I Found it"+ (String)obj.type);
                retType = (String)obj.type ;
            }else{//Object is null. No such variable in the current class.Search in the API's
                StringTokenizer str = new StringTokenizer(p.name.name,".");
                obj = (varSymObject)symtable.lookup(str.nextToken());
                if(obj==null){//No such Object exisits
                    error("Undefined Variable Here");
                }else{
                    String classname = obj.type ;
                    JParserUtil jps = new JParserUtil();
                    if(!jps.isClassLoadAvail(classname)){//No such class
                        error("No Such Class");
                    }
                    String fieldname = str.nextToken();
                    Class temp = jps.isFieldFound(classname,fieldname);
                    if(temp!=null){
                        if(jps.isPublicFinalField(classname,fieldname)==false){
                            error("The Variable is not a Public Variable or a Final Variable");
                        }
                        retType = temp.toString();
                    }else{
                        error("No such Field Exists");
                    }
                }
            }
            return retType ;
    }

    public Object visitUnaryOpExpression(UnaryOpExpression p, Object arg) {
        System.out.println("In Visit UnaryOp Expression") ;
   String type = (String) p.exp.visit(this, null) ;
   if (p.op.terminal.equals("+") || p.op.terminal.equals("-")){
        if (!type.equals("int")){
       error("Unary op +/- expr type not int") ;
        }
   }else{
            error("Unary Op not +/-");
        }
        return type ;
    }

    public Object visitWhileCommand(WhileCommand p, Object arg) {
        System.out.println("In Visit While Command ") ;
   String t1 = (String)p.expression.visit(this, null) ;
   if (!t1.equals("boolean")){
        error("Return Command of While Command must be boolean") ;
   }
   if (p.command != null){
        p.command.visit(this, null) ;
   }
   return null ;
    }

    public Object visitIntegerLiteralExpression(IntegerLiteralExpression p, Object arg) {
        System.out.println("In Visit Integer Literal Expression");
        p.value = "int" ;
        return "int" ;
    }

    public Object visitBooleanLiteralExpression(BooleanLiteralExpression p, Object arg) {
        System.out.println("In Visit Boolean Literal Expression");
        p.value = "boolean" ;
        return "boolean" ;
    }

    public Object visitNullLiteralExpression(NullLiteralExpression p, Object arg) {
        System.out.println("In Visit Null Literal Expression");
        p.value = "null" ;
        return "null" ;
    }

    public Object visitTerminal(Terminal p,Object arg){
        System.out.println("In Visit Terminal");
        return null ;
    }

    public Object visitModifier(Modifier p, Object arg) {
        System.out.println("In Visit Modifier");
        return null ;
    }

    public Object visitStatic(Static p, Object arg) {
        System.out.println("In Visit Static");
        return null ;
    }

    public Object visitPrimitiveType(PrimitiveType p,Object arg){
        System.out.println("In Visit Primitive Type");
        return((String)p.primitivetype.terminal);
    }

    public Object visitReferenceType(ReferenceType p,Object arg){
        System.out.println("In Visit Reference Type");
        return((String)p.name.name);
    }

    public Object visitName(Name p,Object arg){
        System.out.println("In Visit Name");
        return null ;
    }

    public static void main(String args[]) throws Exception{
   //open file name given in command line
        JParser p = new JParser(args[0]);
        AST tree = p.parse() ;
   JContextChecker cc = new JContextChecker() ;
   cc.check(tree) ;
   System.out.println(""+cc.symtable) ;
    }

}

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