Update main.rs

Author: 梶塚太智

src/main.rs

@@ -573,13 +573,10 @@ impl Executor {
  "while" => {
  let cond = self.pop_stack().get_string();
  let code = self.pop_stack().get_string();
- loop {
- if {
- self.evaluate_program(cond.clone());
- !self.pop_stack().get_bool()
- } {
- break;
- }
+ while {
+ self.evaluate_program(cond.clone());
+ self.pop_stack().get_bool()
+ } {
  self.evaluate_program(code.clone());
  }
  }