Add support for array concatenation

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Features
 
 * Decode logs returned by `Transaction.getReceipt()` when available in ABI
+* Add support for array concatenation
 
 ### Other changes
 

src/interpreter/value.rs

@@ -601,6 +601,11 @@ impl Add for Value {
                 Ok(Value::Int(I256::from_raw(a) + b, s1.max(s2)))
             }
             (Value::Str(a), Value::Str(b)) => return Ok(Value::Str(a + &b)),
+            (Value::Array(a, t1), Value::Array(b, t2)) if t1 == t2 => {
+                let mut new_arr = a.clone();
+                new_arr.extend(b);
+                return Ok(Value::Array(new_arr, t1));
+            }
             _ => bail!(error_msg),
         }
         .and_then(Value::validate_int)
@@ -691,6 +696,29 @@ impl Rem for Value {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_add() {
+        assert_eq!(
+            (Value::from(1u64) + Value::from(2u64)).unwrap(),
+            Value::from(3u64)
+        );
+
+        assert_eq!(
+            (Value::from("foo") + Value::from("bar")).unwrap(),
+            Value::from("foobar")
+        );
+
+        assert_eq!(
+            (Value::Array(vec![Value::from(1u64)], Box::new(Type::Uint(256)))
+                + Value::Array(vec![Value::from(2u64)], Box::new(Type::Uint(256))))
+            .unwrap(),
+            Value::Array(
+                vec![Value::from(1u64), Value::from(2u64)],
+                Box::new(Type::Uint(256))
+            )
+        );
+    }
+
     #[test]
     fn test_value_from_hex() {
         let addr = Address::from_hex("0x7a250d5630b4cf539739df2c5dacb4c659f2488d").unwrap();