refactor(tazjin/rlox): Add Interpreter trait for switching impls

Change-Id: Iae28d64ce879014c5e5d7e145c536c1f16ad307d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2418
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/rlox/src/bytecode/errors.rs

@@ -1,3 +1,5 @@
+use std::fmt;
+
 #[derive(Debug)]
 pub enum ErrorKind {
     // CompileError,
@@ -10,4 +12,10 @@ pub struct Error {
     pub kind: ErrorKind,
 }
 
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[line NYI] Error: {:?}", self.kind)
+    }
+}
+
 pub type LoxResult<T> = Result<T, Error>;