options { JAVA_UNICODE_ESCAPE = true; } PARSER_BEGIN(BabyJavaParser) public class BabyJavaParser {} PARSER_END(BabyJavaParser) SKIP : /* WHITE SPACE */ { " " | "\t" | "\n" | "\r" | "\f" } SPECIAL_TOKEN : /* COMMENTS */ { | | } TOKEN : { < LPAREN: "(" > | < RPAREN: ")" > | < LSQPAREN: "[" > | < RSQPAREN: "]" > | < LBRACE: "{" > | < RBRACE: "}" > | < SEMICOLON: ";" > | < COMMA: "," > | < DOT: "." > | < EQ: "==" > | < ASSIGN: "=" > | < PLUS: "+" > | < MINUS: "-" > | < BOOLEAN: "boolean" > | < CLASS: "class" > | < INTERFACE: "interface" > | < INSTANCEOF: "instanceof" > | < ELSE: "else" > | < EXTENDS: "extends" > | < FALSE: "false" > | < IF: "if" > | < IMPLEMENTS: "implements" > | < INTEGER: "int" > | < MAIN: "main" > | < NEW: "new" > | < PUBLIC: "public" > | < RETURN: "return" > | < STATIC: "static" > | < STRING: "String" > | < THIS: "this" > | < TRUE: "true" > | < PRINT: "System.out.println" > | < VOID: "void" > } TOKEN : /* LITERALS */ { < INTEGER_LITERAL: ( ["1"-"9"] (["0"-"9"])* | "0" ) > } TOKEN : /* IDENTIFIERS */ { < IDENTIFIER: (|)* > | < #LETTER: [ "\u0024", "\u0041"-"\u005a", "\u005f", "\u0061"-"\u007a", "\u00c0"-"\u00d6", "\u00d8"-"\u00f6", "\u00f8"-"\u00ff", "\u0100"-"\u1fff", "\u3040"-"\u318f", "\u3300"-"\u337f", "\u3400"-"\u3d2d", "\u4e00"-"\u9fff", "\uf900"-"\ufaff" ] > | < #DIGIT: [ "\u0030"-"\u0039", "\u0660"-"\u0669", "\u06f0"-"\u06f9", "\u0966"-"\u096f", "\u09e6"-"\u09ef", "\u0a66"-"\u0a6f", "\u0ae6"-"\u0aef", "\u0b66"-"\u0b6f", "\u0be7"-"\u0bef", "\u0c66"-"\u0c6f", "\u0ce6"-"\u0cef", "\u0d66"-"\u0d6f", "\u0e50"-"\u0e59", "\u0ed0"-"\u0ed9", "\u1040"-"\u1049" ] > } /**************************************** * The BabyJava Grammar Starts Here * ****************************************/ void Goal() : {} { MainClass() ( TypeDeclaration() )* } void MainClass() : {} { "class" Identifier() "{" "public" "static" "void" "main" "(" "String" "[" "]" Identifier() ")" MethodBody() "}" } void TypeDeclaration() : {} { LOOKAHEAD(3) InterfaceDeclaration() | InterfaceExtends() | ClassDeclaration() } void InterfaceDeclaration() : {} { "interface" Identifier() InterfaceBody() } void InterfaceExtends() : {} { "interface" Identifier() "extends" Identifier() InterfaceBody() } void InterfaceBody() : {} { "{" ( InterfaceMember() )* "}" } void InterfaceMember() : {} { ResultType() Identifier() "(" ( FormalParameterList() )? ")" ";" } void ClassDeclaration() : {} { "class" Identifier() "implements" Identifier() "{" ( ClassBodyDeclaration() )* "}" } void ClassBodyDeclaration() : {} { FieldDeclaration() | MethodDeclaration() } void FieldDeclaration() : {} { Type() Identifier() ";" } void MethodDeclaration() : {} { "public" ResultType() Identifier() "(" ( FormalParameterList() )? ")" MethodBody() } void FormalParameterList() : {} { FormalParameter() ( FormalParameterRest() )* } void FormalParameter() : {} { Type() Identifier() } void FormalParameterRest() : {} { "," FormalParameter() } void MethodBody() : {} { "{" StatementList() ( ReturnStatement() )? "}" } void StatementList() : {} { ( Statement() )* } void Type() : {} { BooleanType() | IntegerType() | ClassOrInterfaceName() } void BooleanType() : {} { "boolean" } void IntegerType() : {} { "int" } void ClassOrInterfaceName() : {} { Identifier() } void ResultType() : {} { VoidType() | Type() } void VoidType() : {} { "void" } void Block() : {} { "{" StatementList() "}" } void ReturnStatement() : {} { "return" Expression() ";" } void Statement() : {} { LOOKAHEAD( VarRef() "=" Expression() ";" ) AssignmentStatement() | IfStatement() | LOOKAHEAD( PrimaryExpression() "." Identifier() "(" ) MessageSendStatement() | PrintStatement() } void AssignmentStatement() : {} { VarRef() "=" Expression() ";" } void IfStatement() : {} { "if" "(" Expression() ")" Block() "else" Block() } void MessageSendStatement() : {} { PrimaryExpression() "." Identifier() "(" ( ExpressionList() )? ")" ";" } void PrintStatement() : {} { "System.out.println" "(" Expression() ")" ";" } void Expression() : {} { LOOKAHEAD( PrimaryExpression() "==" ) CompareExpression() | LOOKAHEAD( PrimaryExpression() "+" ) PlusExpression() | LOOKAHEAD( PrimaryExpression() "-" ) MinusExpression() | LOOKAHEAD( PrimaryExpression() "." Identifier() "(" ) MessageSend() | LOOKAHEAD( "(" ClassOrInterfaceName() ")" Expression()) TypeCast() | LOOKAHEAD( VarRef() "instanceof" ) InstanceOf() | LOOKAHEAD( VarRef() ) VarRef() | PrimaryExpression() } void ExpressionList() : {} { Expression() ( ExpressionRest() )* } void ExpressionRest() : {} { "," Expression() } void CompareExpression() : {} { PrimaryExpression() "==" PrimaryExpression() } void PlusExpression() : {} { PrimaryExpression() "+" PrimaryExpression() } void MinusExpression() : {} { PrimaryExpression() "-" PrimaryExpression() } void MessageSend() : {} { PrimaryExpression() "." Identifier() "(" ( ExpressionList() )? ")" } void TypeCast() : {} { "(" ClassOrInterfaceName() ")" Expression() } void InstanceOf() : {} { VarRef() "instanceof" ClassOrInterfaceName() } void PrimaryExpression() : {} { IntegerLiteral() | TrueLiteral() | FalseLiteral() | ThisExpression() | AllocationExpression() | SubExpression() | Identifier() } void IntegerLiteral() : {} { } void TrueLiteral() : {} { "true" } void FalseLiteral() : {} { "false" } void Identifier() : {} { } void ThisExpression() : {} { "this" } void AllocationExpression() : {} { "new" Identifier() "(" ")" } void SubExpression() : {} { "(" Expression() ")" } void VarRef() : {} { LOOKAHEAD(4) DotExpression() | LOOKAHEAD(2) Identifier() } void DotExpression() : {} { Identifier() "." Identifier() }