add box type

extlib/benz/gc.c

@@ -490,6 +490,12 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
     }
     break;
   }
+  case PIC_TT_BOX: {
+    struct pic_box *box = (struct pic_box *)obj;
+
+    gc_mark(pic, box->value);
+    break;
+  }
   case PIC_TT_NIL:
   case PIC_TT_BOOL:
 #if PIC_ENABLE_FLOAT
@@ -737,6 +743,9 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_CP: {
     break;
   }
+  case PIC_TT_BOX: {
+    break;
+  }
   case PIC_TT_NIL:
   case PIC_TT_BOOL:
 #if PIC_ENABLE_FLOAT

extlib/benz/include/picrin.h

@@ -268,6 +268,7 @@ pic_value pic_fdisplay(pic_state *, pic_value, xFILE *);
 #include "picrin/symbol.h"
 #include "picrin/vector.h"
 #include "picrin/reg.h"
+#include "picrin/box.h"
 
 #if defined(__cplusplus)
 }

extlib/benz/include/picrin/box.h

@@ -0,0 +1,53 @@
+/**
+ * See Copyright Notice in picrin.h
+ */
+
+#ifndef PICRIN_BOX_H
+#define PICRIN_BOX_H
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+struct pic_box {
+  PIC_OBJECT_HEADER
+  pic_value value;
+};
+
+#define pic_box_p(v) (pic_type(v) == PIC_TT_BOX)
+#define pic_box_ptr(o) ((struct pic_box *)pic_ptr(o))
+
+PIC_INLINE pic_value
+pic_box(pic_state *pic, pic_value value)
+{
+  struct pic_box *box;
+
+  box = (struct pic_box *)pic_obj_alloc(pic, sizeof(struct pic_box), PIC_TT_BOX);
+  box->value = value;
+
+  return pic_obj_value(box);
+}
+
+PIC_INLINE pic_value
+pic_unbox(pic_state *pic, pic_value box)
+{
+  if (! pic_box_p(box)) {
+    pic_errorf(pic, "box required");
+  }
+  return pic_box_ptr(box)->value;
+}
+
+PIC_INLINE void
+pic_set_box(pic_state *pic, pic_value box, pic_value value)
+{
+  if (! pic_box_p(box)) {
+    pic_errorf(pic, "box required");
+  }
+  pic_box_ptr(box)->value = value;
+}
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif

extlib/benz/include/picrin/value.h

@@ -163,10 +163,11 @@ enum pic_tt {
   PIC_TT_DATA,
   PIC_TT_DICT,
   PIC_TT_REG,
+  PIC_TT_BOX,
   PIC_TT_RECORD,
   PIC_TT_CXT,
   PIC_TT_IREP,
-  PIC_TT_CP
+  PIC_TT_CP,
 };
 
 #define PIC_OBJECT_HEADER			\
@@ -337,6 +338,8 @@ pic_type_repr(enum pic_tt tt)
     return "reg";
   case PIC_TT_RECORD:
     return "record";
+  case PIC_TT_BOX:
+    return "box";
   case PIC_TT_CP:
     return "checkpoint";
   }