write function should be print even env objects

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

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;
   }
 }