refine behavior of Show::to_string(Bytes)

builtin/show.mbt

@@ -39,7 +39,29 @@ pub impl Show for Byte with output(self, logger) {
 }
 
 pub impl Show for Bytes with output(self, logger) {
-  logger.write_string(self.to_string())
+  fn to_hex_digit(i : Int) -> Char {
+    if i < 10 {
+      Char::from_int('0'.to_int() + i)
+    } else {
+      Char::from_int('a'.to_int() + (i - 10))
+    }
+  }
+
+  logger.write_string("b\"")
+  for i = 0; i < self.length(); i = i + 1 {
+    let byte = self[i].to_int()
+    logger
+    ..write_string("\\x")
+    ..write_char(to_hex_digit(byte / 16))
+    .write_char(to_hex_digit(byte % 16))
+  }
+  logger.write_string("\"")
+}
+
+pub impl Show for Bytes with to_string(self) {
+  let buf = Buffer::new()
+  Show::output(self, buf)
+  buf.to_string()
 }
 
 pub impl Show for String with output(self, logger) {

bytes/bytes_test.mbt

@@ -12,9 +12,29 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+test "bytes literal" {
+  inspect!(
+    b"ABC",
+    content=
+      #|b"\x41\x42\x43"
+    ,
+  )
+  inspect!(
+    b"\x41\x42\x43",
+    content=
+      #|b"\x41\x42\x43"
+    ,
+  )
+}
+
 test "from_array" {
   let b = @bytes.of([b'\x41', b'\x00', b'\x42', b'\x00', b'\x43', b'\x00'])
-  inspect!(b, content="ABC")
+  inspect!(
+    b,
+    content=
+      #|b"\x41\x00\x42\x00\x43\x00"
+    ,
+  )
 }
 
 test "hash" {