Move to Display rather than Debug for simple script runner

src/main.rs

@@ -1,7 +1,7 @@
 use std::env;
 use std::fs::File;
 use std::io::prelude::*;
-use std::fmt::Debug;
+use std::fmt::Display;
 
 mod engine;
 use engine::Engine;
@@ -21,10 +21,6 @@ mod parser;
 // * Method/dot access
 // * Comparison ops
 
-fn showit<T: Debug>(x: &mut T) -> () {
-    println!("{:?}", x)
-}
-
 /*
 fn simple_fn(x: i32) -> bool { x == 1 }
 fn simple_fn2(x: &mut i32) -> bool { x.clone() == 2 }
@@ -174,6 +170,10 @@ fn test_var_scope() {
     }
 }
 
+fn showit<T: Display>(x: &mut T) -> () {
+    println!("{}", x)
+}
+
 fn main() {
     let mut engine = Engine::new();
     &(showit as fn(x: &mut i32)->()).register(&mut engine, "print");