Question

Write the BNF for mini Java language based of the following information:

Data Types

• Integer
  • Int
  • Long
• Double
• Boolean
• Char
• References

Complex Data Structures

• Arrays
  • int v[30];
• Classes
  • member variables
    • class Name {
    • int a;
    • char b;
    • char name[25];
    • }

Methods

• Return data type
  • Primitive data type
  • Void
• Method Name
• Parameter list
  • Could be empty
• Statement Block
  • {
  • Variable declarations
  • Executable Statements
  • }

Program

• Variable Declarations
• Class Definitions
• Methods
• Only one method named "main" but must have one method named main

Statements

• Expression Statements
  • Assignment operation allowed in expressions
  • Add, Sub, Mult, Divd, 6 comparisons, Logical operations (and, or, not), Assignment
• If statements
  • else is allowed but optional
• While statements
• Print
  • eol value to go to new line
  • allow multiple print items
• Return statement - returns the value of an expression

Statement Blocks

• Enclosed in braces
• Separate statements using semicolons

Answer 1

Types

Type:
        PrimitiveType
        ReferenceType
PrimitiveType:
        int
        boolean
ReferenceType:
        ClassType
        ArrayType
ClassType:
        Name
ArrayType:
        PrimitiveType [ ]
        ClassType [ ]
        ArrayType [ ]

Names

Name:
        SimpleName
        QualifiedName
SimpleName:
        Identifier
QualifiedName:
        Name . Identifier

Packages

CompilationUnit:
        TypeDeclaration*
TypeDeclaration:
        ClassDeclaration
        ;

Modifiers

Modifiers:
        Modifier*
Modifier:
        public
        static
        native

Classes

Class Declaration

ClassDeclaration:
        class Identifier Superopt ClassBody
Super:
        extends ClassType
ClassBody:
        { ClassMemberDeclaration* }
ClassMemberDeclaration:
        FieldDeclaration
        MethodDeclaration

Field Declarations

FieldDeclaration:
        Modifiers Type IdentifierList ;
IdentifierList:
        Identifier
        IdentifierList , Identifier

Method Declarations

MethodDeclaration:
        MethodHeader MethodBody
MethodHeader:
        Modifiers Type MethodDeclarator Throwsopt
        Modifiers void MethodDeclarator Throwsopt
MethodDeclarator:
        Identifier ( FormalParameterListopt )
FormalParameterList:
        FormalParameter
        FormalParameterList , FormalParameter
FormalParameter:
        Type Identifier
Throws:
        throws ClassType
MethodBody:
        Block
        ;

Blocks and Statements

Block:
        { BlockStatement* }
BlockStatement:
        LocalVariableDeclarationStatement
        Statement
LocalVariableDeclarationStatement:
        LocalVariableDeclaration ;
LocalVariableDeclaration:
        Type VariableDeclarators
VariableDeclarators:
        VariableDeclarator
        VariableDeclarators , VariableDeclarator
VariableDeclarator:
        Identifier
        Identifier = Expression
Statement:
        Block
        ExpressionStatement
        IfThenStatement
        IfThenElseStatement
        WhileStatement
        DoWhileStatement
        ReturnStatement
        BreakStatement
        ContinueStatement
        ForStatement
ExpressionStatement:
        StatementExpressionopt ;
StatementExpression:
        Expression
IfThenStatement:
        if ( Expression ) Statement
IfThenElseStatement:
        if ( Expression ) Statement else Statement
WhileStatement:
        while ( Expression ) Statement
DoWhileStatement:
        do Statement while ( Expression ) ;
ReturnStatement:
        return Expressionopt ;
BreakStatement:
        break ;
ContinueStatement:
        continue ;
ForStatement:
        for ( ForInitopt ; Expressionopt ; ForUpdateopt ) Statement
ForInit:
        StatementExpressionList
        LocalVariableDeclaration
ForUpdate:
        StatementExpressionList
StatementExpressionList:
        StatementExpression
        StatementExpressionList , StatementExpression

Expressions

Expression:
        ConditionalExpression
        AssignmentExpression
AssignmentExpression:
        ConditionalExpression = Expression
ConditionalExpression:
        InfixExpression
        InfixExpression ? Expression : ConditionalExpression
InfixExpression:
        PrefixExpression
        InfixExpression InfixOp PrefixExpression
InfixOp:
        ||
        &&
        ==
        !=
        <
        >
        <=
        >=
        +
        -
        *
        /
PrefixExpression:
        PrefixOp PrefixExpression
        PostfixExpression
PrefixOp:
        -
        !
PostfixExpression:
        Primary Suffix*
Suffix:
        ArrayAccess
        FieldAccess
        MethodInvocation
ArrayAccess:
        [ Expression ]
Selector:
        . Identifier
FieldAccess:
        Selector
MethodInvocation:
        Selector ( ArgumentListopt )
ArgumentList:
        Expression
        ArgumentList , Expression
Primary:
        ( Expression )
        this
        Literal
        Identifier
        super FieldAccess
        super MethodInvocation
        ClassInstanceCreationExpression
        ArrayCreationExpression
ClassInstanceCreationExpression:
        new ClassType ( )
ArrayCreationExpression:
        new PrimitiveType [ Expression ] Dimension*
        new ClassType [ Expression ] Dimension*
Dimension:
        [ ]