Provide a nice Display impl for ValueKind::{Array, Table}

This patch changes the Display impl for ValueKind so that Array and
Table are nicely displayed.
This basically changes a user-facing implementation in a
non-backwards-compatible way. But as the documentation for std states:

    Display is similar to Debug, but Display is for user-facing output
    [...]

This is user-facing and I'd say this is okay.

Signed-off-by: Matthias Beyer <[email protected]>

Author: matthiasbeyer

src/value.rs

@@ -94,10 +94,15 @@ impl Display for ValueKind {
             ValueKind::Integer(value) => write!(f, "{}", value),
             ValueKind::Float(value) => write!(f, "{}", value),
             ValueKind::Nil => write!(f, "nil"),
-
-            // TODO: Figure out a nice Display for these
-            ValueKind::Table(ref table) => write!(f, "{:?}", table),
-            ValueKind::Array(ref array) => write!(f, "{:?}", array),
+            ValueKind::Table(ref table) => write!(f, "{{ {} }}", {
+                table
+                    .iter()
+                    .map(|(k, v)| format!("{} => {}, ", k, v))
+                    .collect::<String>()
+            }),
+            ValueKind::Array(ref array) => write!(f, "{:?}", {
+                array.iter().map(|e| format!("{}, ", e)).collect::<String>()
+            }),
         }
     }
 }