def __unary(self) -> Expr:
if self.__match(TokenType.BANG, TokenType.MINUS):
operator = token_to_unary_operator(self.__previous())
inner_expr = self.__unary()
expr = exprs.Unary(operator, inner_expr)
expr.span = SourceSpan.from_spans(operator.span, inner_expr.span)
return expr
return self.__primary()
def __multiplication(self) -> Expr:
expr = self.__unary()
while self.__match(TokenType.SLASH, TokenType.STAR):
operator = token_to_binary_operator(self.__previous())
right = self.__unary()
new_expr = exprs.Binary(expr, operator, right)
new_expr.span = SourceSpan.from_spans(expr.span, right.span)
expr = new_expr
return expr
def __equality(self) -> Expr:
expr = self.__comparison()
while self.__match(TokenType.BANG_EQUAL, TokenType.EQUAL_EQUAL):
operator = token_to_binary_operator(self.__previous())
right = self.__comparison()
new_expr = exprs.Binary(expr, operator, right)
new_expr.span = SourceSpan.from_spans(expr.span, right.span)
expr = new_expr
return expr
def __comparison(self) -> Expr:
expr = self.__addition()
while self.__match(TokenType.GREATER, TokenType.GREATER_EQUAL, TokenType.LESS, TokenType.LESS_EQUAL):
operator = token_to_binary_operator(self.__previous())
right = self.__addition()
new_expr = exprs.Binary(expr, operator, right)
new_expr.span = SourceSpan.from_spans(expr.span, right.span)
expr = new_expr
return expr
def __primary(self) -> Expr:
def literal(value) -> Expr:
expr = exprs.Literal(value)
expr.span = self.__previous().span
return expr
if self.__match(TokenType.FALSE):
return literal(False)
if self.__match(TokenType.TRUE):
return literal(True)
if self.__match(TokenType.NUMBER, TokenType.STRING):
return literal(self.__previous().literal)
if self.__match(TokenType.LEFT_PAREN):
start = self.__previous()
expr = exprs.Grouping(self.expression())
end = self.__consume(TokenType.RIGHT_PAREN, 'Expected \')\' after expression')
expr.span = SourceSpan.from_spans(start.span, end.span)
return expr
raise ParserException(self.__peek(), 'Expected expression')