Course Project Fall 2021

Token ::= Symbol | Keyword | Identifier | IntLiteral | StringLiteral Symbol::= =|,|;|:|(|)|[|]|&&||||<|>|==|!= |!|+|-||/ Keyword::= VAR | VAL | FUN | DO | END | LET | SWITCH | CASE | DEFAULT |IF |WHILE |RETURN |NIL |TRUE |FALSE| INT| STRING | BOOLEAN | LIST Identifier::= (a..z|A..Z||$) (a..z|A..Z||$|0..9) IntLiteral::= ( 0 .. 9 ) + StringLiteral::= "((|“)|EscapeSeq)*“ | ‘((|‘)|EscapeSeq)‘ EscapeSeq::= \b |\t |\n |\r| \f |\” |\’ |\ Comment /(* | */)*/ WhiteSpace ::= space | tab | NL | CR (denoted in Java as ‘ ‘, ‘\t’, ‘\n’ and ‘\r’) White space and comments separate tokens, but otherwise are ignored. Notation: X+ means one or more instances of X. ~a means any character other than a.

Program ::= Declaration* Declaration::= Function | VAR NameDef (= Expression)? ; | VAL NameDef = Expression ; Function::= FUN Identifier ( ( NameDef (, NameDef)* )? ) (: Type)? DO Block END Block::= Statement* NameDef::= Identifier (: Type)? Statement::= LET NameDef (= Expression)? ; | SWITCH Expression ( CASE Expression : Block )* DEFAULT Block END | IF Expression DO Block END | WHILE Expression DO Block END | RETURN Expression ; | Expression (= Expression)? ; Expression::= LogicalExpression LogicalExpression returns Expression::= ComparisonExpression ( ( && | || ) ComparisonExpression)* ComparisonExpression ::= AdditiveExpression ( ( < | > | == | != ) AdditiveExpression)* AdditiveExpression ::= MultiplicativeExpression ( ( + |- ) MultiplicativeExpression )* MultiplicativeExpression returns Expression ::= UnaryExpression ( ( * | / ) UnaryExpression)* UnaryExpression returns Expression::= (! | - )? PrimaryExpression PrimaryExpression ::= NIL | TRUE | FALSE | IntLiteral | StringLiteral | ( Expression ) | Identifier ( (Expression ( , Expression)* )? ) | Identifier | Identifier [ Expression ] Type: INT | STRING | BOOLEAN | LIST [ Type ]

Program::= {Program} declarations += Declaration* Declaration::= {Function} 'FUN' name= Identifier '(' ( arguments += NameDef (',' arguments += NameDef)* )? ')' (':' resultType = Type)? 'DO' block = Block 'END' | {MutableGlobal} 'VAR' varDef = NameDef ('=' expression=Expression)? ';' | {ImmutableGlobal} 'VAL' valDef = NameDef '=' expression = Expression ';' Block::= {Block} statements += Statement* NameDef::= {NameDef} name = Identifier (':' type = Type)? Statement::= {LetStatement} 'LET' localDef = NameDef ('=' expression= Expression)? 'BEGIN' block = Block 'END' | {SwitchStatement} 'SWITCH' switchExpr = Expression ( 'CASE' branchExprs += Expression ':' blocks += Block )* 'DEFAULT' defaultBlock = Block 'END'| {IfStatement} 'IF' guardExpr = Expression 'DO' ifBlock = Block 'END' | {WhileStatement} 'WHILE' guardExpression = Expression 'DO' block = Block 'END' | {ReturnStatement} 'RETURN' returnExpr = Expression ';' | {AssignmentStatement} leftExpr=Expression ( '=' rightExpr = Expression)? ';' ; Expression::= LogicalExpression LogicalExpression returns{Expression}::= {BinaryExpression} ComparisonExpression ( op = ('&&' | '||') ComparisonExpression)* ComparisonExpression returns{Expression}::= {BinaryExpression} AdditiveExpression ( op = ('<' | '>' | '==' | '!=') AdditiveExpression)* AdditiveExpression returns{Expression}::= {BinaryExpression} MultiplicativeExpression ( op = ('+'|'-') MultiplicativeExpression )* MultiplicativeExpression returns{Expression}::= {BinaryExpression} UnaryExpression ( op=(''|'/') UnaryExpression ) UnaryExpression returns {Expression}::= {UnaryExpression} op = ('!'|'-')? expression = PrimaryExpression PrimaryExpression returns {Expression}::= {NilConstantExpression} 'NIL' |

{BooleanLiteralExpression} value = ('TRUE' | 'FALSE') | {IntLiteralExpression} value = INT | {StringLiteralExpression} value = STRING | '(' Expression ')'| {FunctionCallExpression} name = Identifier '(' (arguments += Expression (',' argumnets += Expression)* )? ')' | {IdentExpression} name = Identifier | {ListSelectorExpression} name = Identifier '[' index = Expression ']' Type returns {Type}::= {PrimitiveType} type = ('INT' | 'STRING' | 'BOOLEAN') | {ListType}'LIST' '[' (type = Type)? ']' Identifier::= {Identifier} name = ID