def for_statement(self):
self._consume(TokenType.LEFT_PAREN, "Expect '(' after 'for'.")
if self._match([TokenType.SEMICOLON]):
initializer = None
elif self._match([TokenType.VAR]):
initializer = self.var_declaration()
else:
initializer = self.expression()
condition = Expr.Literal(True)
if not self._check(TokenType.SEMICOLON):
condition = self.expression()
self._consume(TokenType.SEMICOLON, "Expect ';' after loop condition.")
incrementor = None
if not self._check(TokenType.RIGHT_PAREN):
incrementor = self.expression()
self._consume(TokenType.RIGHT_PAREN, "Expect ') after for clauses.")
body = self.statement()
# Lox Code - `for (var a = 0; a < 3; a = a + 1) print a;`
# is ~transalated~ desugared into:
# { // This additional Block limits the scope
# var a = 0;
# while (a < 3){
# print a;
# a = a + 1;
# }
# }
if incrementor != None:
body = Stmt.Block([body, incrementor])
body = Stmt.While(condition, body)
if initializer != None:
body = Stmt.Block([initializer, body])
return body
def while_statement(self):
self._consume(TokenType.LEFT_PAREN, "Expect ')' after while.")
condition = self.expression()
self._consume(TokenType.RIGHT_PAREN, "Expect ')' after condition.")
body = self.statement()
return Stmt.While(condition, body)