diff --git a/include/picrin/port.h b/include/picrin/port.h
index c421bb11..a2c7e472 100644
--- a/include/picrin/port.h
+++ b/include/picrin/port.h
@@ -23,6 +23,9 @@ struct pic_port {
 };
 
 #define pic_port_p(v) (pic_type(v) == PIC_TT_PORT)
+#define pic_env_p(v) (pic_type(v) == PIC_TT_ENV)
+
 #define pic_port_ptr(v) ((struct pic_port *)(v).u.data)
+#define pic_env_ptr(v) ((struct pic_env *)(v).u.data)
 
 #endif
diff --git a/src/port.c b/src/port.c
index fbe75c67..0dfc6c50 100644
--- a/src/port.c
+++ b/src/port.c
@@ -65,7 +65,8 @@ write(pic_state *pic, pic_value obj)
     printf(")");
     break;
   case PIC_TT_ENV:
-    pic_abort(pic, "logic flaw");
+    printf("#<env %p>", pic_env_ptr(obj));
+    break;
   }
 }