clone_fix.diff

--- code.rs 2017-10-16 10:34:52.866213600 -0600
+++ code_fixed_with_clone.rs    2017-10-16 10:34:38.033128000 -0600
@@ -54,7 +54,7 @@
     }

     fn read_op(&mut self) -> Token {
-        let ch = self.input.next().unwrap();
+        let ch = self.input.next().unwrap().clone();
         if ch == '+' {
             Plus(ch)
         } else {
@@ -64,13 +64,13 @@


     pub fn next(&mut self) ->  Token {
-        let ch = self.input.peek();
+        let ch = self.input.peek().cloned();
         match ch {
             Some(c) => {
                 self.pos += 1;
                 if c.is_digit(10) {
                     self.read_number()
-                } else if *c == '+' || *c == '-' {
+                } else if c == '+' || c == '-' {
                     self.read_op()
                 } else if c.is_whitespace() {
                     self.next()