Purple Grammar Documentation

Grammar

This file contains the BNF grammar for Purple in a format recognized by ANTLR4.

grammar purple;
 
tokens {
    T_IDENTIFIER,
    T_INTEGER_LITERAL,
    T_CHAR_LITERAL
}
 
booleanLiteral: 'true'
              | 'false'
              ;
 
type: 'void'
    | 'bool'
    | 'char'
    | 'int'
    | 'long'
    ;
 
assignmentOperator: '='
                  ;
 
literal: T_INTEGER_LITERAL
       | T_CHAR_LITERAL
       | booleanLiteral
       ;
 
primaryExpression: T_IDENTIFIER
                 | literal
                 ;
 
postfixExpression: primaryExpression
                 ;
 
unaryExpression: postfixExpression
               ;
 
castExpression: unaryExpression
              ;
 
multiplicativeExpression: castExpression
                        | multiplicativeExpression '*' castExpression
                        | multiplicativeExpression '/' castExpression
                        ;
 
additiveExpression: multiplicativeExpression
                  | additiveExpression '+' multiplicativeExpression
                  | additiveExpression '-' multiplicativeExpression
                  ;
 
shiftExpression: additiveExpression
               ;
 
relationalExpression: shiftExpression
                    | relationalExpression '<' shiftExpression
                    | relationalExpression '>' shiftExpression
                    | relationalExpression '<=' shiftExpression
                    | relationalExpression '>=' shiftExpression
                    ;
 
equalityExpression: relationalExpression
                  | equalityExpression '==' relationalExpression
                  | equalityExpression '!=' relationalExpression
                  ;
 
andLogicalExpression: equalityExpression
                    | andLogicalExpression 'and' equalityExpression
                    ;
 
xorLogicalExpression: andLogicalExpression
                    | xorLogicalExpression 'xor' andLogicalExpression
                    ;
 
orLogicalExpression: xorLogicalExpression
                   | orLogicalExpression 'or' xorLogicalExpression
                   ;
 
constantExpression: orLogicalExpression
                  ;
 
assignmentExpression: orLogicalExpression
                    | unaryExpression assignmentOperator assignmentExpression
                    ;
 
booleanExpression: booleanLiteral
                 | constantExpression
                 ;
 
expression: booleanExpression
          ;
 
printStatement: 'print' expression 
              ;
 
declareStatement: type T_IDENTIFIER
                ;
 
ifStatement: 'if' '(' expression ')' statements
           | 'if' '(' expression ')' statements 'else' statements
           ;
 
whileStatement: 'while' '(' expression ')' statements
              | 'while' '(' expression ')' statements 'else' statements
              ;
 
forStatement: 'for' '(' expression ';' expression ';' expression ')' statements
            ;
 
loopStatement: whileStatement
             | forStatement
             ;
 
functionCallStatement: T_IDENTIFIER '(' expression ')'
                     ;
 
returnStatement: 'return' expression
               ;
 
statementType: printStatement
             | assignmentExpression
             | declareStatement
             | ifStatement
             | loopStatement
             | functionCallStatement
             | returnStatement
             ;
 
statement: statementType ';'
         ;
 
statements: '{' '}'
          | '{' statement '}'
          | '{' statement statements '}'
          ;
 
functionDeclaration: 'void' T_IDENTIFIER '(' 'void' ')' statements;