halp, i cant write a recursive iterator :3

edn/src/edn_token.rs

@@ -55,4 +55,15 @@ impl<'a> Token<'a> {
         }
         Ok(("", state))
     }
+
+    pub fn number (digits: &str) -> usize {
+        let mut value = 0;
+        for c in digits.chars() { value = 10 * value + Self::digit(c); }
+        value
+    }
+
+    pub const fn digit (c: char) -> usize {
+        match c { '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
+                  '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9, _ => unreachable!() }
+    }
 }