diff --git a/Makefile b/Makefile
index 76feae70..419f9598 100644
--- a/Makefile
+++ b/Makefile
@@ -76,7 +76,7 @@ src/init_contrib.c:
 lib/boot.c: piclib/boot.scm
 	bin/picrin-bootstrap tools/mkboot.scm < piclib/boot.scm > lib/boot.c
 
-$(LIBPICRIN_OBJS) $(PICRIN_OBJS) $(CONTRIB_OBJS): lib/include/picrin.h lib/include/picrin/*.h lib/khash.h lib/value.h lib/object.h lib/state.h lib/vm.h
+$(LIBPICRIN_OBJS) $(PICRIN_OBJS) $(CONTRIB_OBJS): lib/include/picrin.h lib/include/picrin/*.h lib/khash.h lib/object.h lib/state.h lib/vm.h
 
 doc: docs/*.rst docs/contrib.rst
 	$(MAKE) -C docs html
diff --git a/contrib/10.callcc/callcc.c b/contrib/10.callcc/callcc.c
index 50513b38..a6994a5b 100644
--- a/contrib/10.callcc/callcc.c
+++ b/contrib/10.callcc/callcc.c
@@ -1,5 +1,4 @@
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/blob.c b/lib/blob.c
index f70ae92c..a597b04a 100644
--- a/lib/blob.c
+++ b/lib/blob.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 pic_value
diff --git a/lib/bool.c b/lib/bool.c
index 73c94b67..576af9bb 100644
--- a/lib/bool.c
+++ b/lib/bool.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 #if PIC_NAN_BOXING
@@ -25,14 +24,14 @@ pic_eqv_p(pic_state *PIC_UNUSED(pic), pic_value x, pic_value y)
 bool
 pic_eq_p(pic_state *PIC_UNUSED(pic), pic_value x, pic_value y)
 {
-  if (value_type(pic, x) != value_type(pic, y))
+  if (pic_type(pic, x) != pic_type(pic, y))
     return false;
 
-  switch (value_type(pic, x)) {
+  switch (pic_type(pic, x)) {
   case PIC_TYPE_NIL:
     return true;
   case PIC_TYPE_TRUE: case PIC_TYPE_FALSE:
-    return value_type(pic, x) == value_type(pic, y);
+    return pic_type(pic, x) == pic_type(pic, y);
   default:
     return obj_ptr(x) == obj_ptr(y);
   }
@@ -41,14 +40,14 @@ pic_eq_p(pic_state *PIC_UNUSED(pic), pic_value x, pic_value y)
 bool
 pic_eqv_p(pic_state *PIC_UNUSED(pic), pic_value x, pic_value y)
 {
-  if (value_type(pic, x) != value_type(pic, y))
+  if (pic_type(pic, x) != pic_type(pic, y))
     return false;
 
-  switch (value_type(pic, x)) {
+  switch (pic_type(pic, x)) {
   case PIC_TYPE_NIL:
     return true;
   case PIC_TYPE_TRUE: case PIC_TYPE_FALSE:
-    return value_type(pic, x) == value_type(pic, y);
+    return pic_type(pic, x) == pic_type(pic, y);
   case PIC_TYPE_FLOAT:
     return pic_float(pic, x) == pic_float(pic, y);
   case PIC_TYPE_INT:
@@ -89,11 +88,11 @@ internal_equal_p(pic_state *pic, pic_value x, pic_value y, int depth, khash_t(m)
   if (pic_eqv_p(pic, x, y)) {
     return true;
   }
-  if (value_type(pic, x) != value_type(pic, y)) {
+  if (pic_type(pic, x) != pic_type(pic, y)) {
     return false;
   }
 
-  switch (value_type(pic, x)) {
+  switch (pic_type(pic, x)) {
   case PIC_TYPE_ID: {
     struct identifier *id1, *id2;
     pic_value s1, s2;
diff --git a/lib/char.c b/lib/char.c
index 21e63e93..8537ac99 100644
--- a/lib/char.c
+++ b/lib/char.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 static pic_value
diff --git a/lib/cont.c b/lib/cont.c
index e488d464..51c15149 100644
--- a/lib/cont.c
+++ b/lib/cont.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/data.c b/lib/data.c
index 6e063da1..3bc65b89 100644
--- a/lib/data.c
+++ b/lib/data.c
@@ -3,13 +3,12 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 bool
 pic_data_p(pic_state *pic, pic_value obj, const pic_data_type *type)
 {
-  if (value_type(pic, obj) != PIC_TYPE_DATA) {
+  if (pic_type(pic, obj) != PIC_TYPE_DATA) {
     return false;
   }
   return type == NULL || pic_data_ptr(pic, obj)->type == type;
diff --git a/lib/debug.c b/lib/debug.c
index 7ba559fd..670abb70 100644
--- a/lib/debug.c
+++ b/lib/debug.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/dict.c b/lib/dict.c
index d579cf2b..71283fab 100644
--- a/lib/dict.c
+++ b/lib/dict.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 KHASH_DEFINE(dict, symbol *, pic_value, kh_ptr_hash_func, kh_ptr_hash_equal)
diff --git a/lib/error.c b/lib/error.c
index 4347578f..b090b97e 100644
--- a/lib/error.c
+++ b/lib/error.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/ext/eval.c b/lib/ext/eval.c
index 41078384..ceadc8c8 100644
--- a/lib/ext/eval.c
+++ b/lib/ext/eval.c
@@ -4,7 +4,6 @@
 
 #include "picrin.h"
 #include "picrin/extra.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 #include "vm.h"
@@ -173,7 +172,7 @@ expand_defmacro(pic_state *pic, pic_value expr, pic_value env)
 static pic_value
 expand_node(pic_state *pic, pic_value expr, pic_value env, pic_value deferred)
 {
-  switch (value_type(pic, expr)) {
+  switch (pic_type(pic, expr)) {
   case PIC_TYPE_ID:
   case PIC_TYPE_SYMBOL: {
     return expand_var(pic, expr, env, deferred);
@@ -498,7 +497,7 @@ analyze_call(pic_state *pic, analyze_scope *scope, pic_value obj)
 static pic_value
 analyze_node(pic_state *pic, analyze_scope *scope, pic_value obj)
 {
-  switch (value_type(pic, obj)) {
+  switch (pic_type(pic, obj)) {
   case PIC_TYPE_SYMBOL: {
     return analyze_var(pic, scope, obj);
   }
@@ -947,7 +946,7 @@ codegen_quote(pic_state *pic, codegen_context *cxt, pic_value obj, bool tailpos)
   int pidx;
 
   obj = pic_list_ref(pic, obj, 1);
-  switch (value_type(pic, obj)) {
+  switch (pic_type(pic, obj)) {
   case PIC_TYPE_UNDEF:
     emit_n(pic, cxt, OP_PUSHUNDEF);
     break;
diff --git a/lib/ext/lib.c b/lib/ext/lib.c
index f569748e..7411307e 100644
--- a/lib/ext/lib.c
+++ b/lib/ext/lib.c
@@ -4,7 +4,6 @@
 
 #include "picrin.h"
 #include "picrin/extra.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/ext/read.c b/lib/ext/read.c
index b5e74618..402b6807 100644
--- a/lib/ext/read.c
+++ b/lib/ext/read.c
@@ -4,7 +4,6 @@
 
 #include "picrin.h"
 #include "picrin/extra.h"
-#include "value.h"
 #include "object.h"
 
 #undef EOF
diff --git a/lib/ext/write.c b/lib/ext/write.c
index 6fe784de..ee874f7d 100644
--- a/lib/ext/write.c
+++ b/lib/ext/write.c
@@ -4,7 +4,6 @@
 
 #include "picrin.h"
 #include "picrin/extra.h"
-#include "value.h"
 #include "object.h"
 
 struct writer_control {
@@ -170,7 +169,7 @@ traverse(pic_state *pic, pic_value obj, struct writer_control *p)
     return;
   }
 
-  switch (value_type(pic, obj)) {
+  switch (pic_type(pic, obj)) {
   case PIC_TYPE_PAIR:
   case PIC_TYPE_VECTOR:
   case PIC_TYPE_DICT: {
@@ -413,7 +412,7 @@ write_dict(pic_state *pic, pic_value dict, pic_value port, struct writer_control
 static const char *
 typename(pic_state *pic, pic_value obj)
 {
-  switch (value_type(pic, obj)) {
+  switch (pic_type(pic, obj)) {
   case PIC_TYPE_NIL:
     return "null";
   case PIC_TYPE_TRUE:
@@ -486,7 +485,7 @@ write_core(pic_state *pic, pic_value obj, pic_value port, struct writer_control
     pic_weak_set(pic, labels, obj, pic_int_value(pic, i));
   }
 
-  switch (value_type(pic, obj)) {
+  switch (pic_type(pic, obj)) {
   case PIC_TYPE_UNDEF:
     pic_fprintf(pic, port, "#undefined");
     break;
diff --git a/lib/gc.c b/lib/gc.c
index b8745cba..26b14a95 100644
--- a/lib/gc.c
+++ b/lib/gc.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/include/picrin.h b/lib/include/picrin.h
index 5c500c32..e185d2e6 100644
--- a/lib/include/picrin.h
+++ b/lib/include/picrin.h
@@ -89,24 +89,14 @@ bool pic_equal_p(pic_state *, pic_value, pic_value);
  * number, boolean, character, string, bytevector, and userdata
  */
 
+#include "picrin/value.h"       /* inline definitions */
+
 typedef struct {
   const char *type_name;
   void (*dtor)(pic_state *, void *);
   void (*mark)(pic_state *, void *, void (*)(pic_state *, pic_value));
 } pic_data_type;
 
-typedef struct {
-  int (*read)(pic_state *, void *, char *, int);
-  int (*write)(pic_state *, void *, const char *, int);
-  long (*seek)(pic_state *, void *, long, int);
-  int (*close)(pic_state *, void *);
-} pic_port_type;
-
-typedef pic_value (*pic_func_t)(pic_state *);
-
-#include "value.h"
-#include "object.h"
-
 bool pic_undef_p(pic_state *, pic_value); /* deprecated */
 bool pic_int_p(pic_state *, pic_value);
 bool pic_float_p(pic_state *, pic_value);
@@ -241,6 +231,7 @@ pic_value pic_sym_name(pic_state *, pic_value sym);
  * procedure
  */
 
+typedef pic_value (*pic_func_t)(pic_state *);
 bool pic_proc_p(pic_state *, pic_value);
 pic_value pic_lambda(pic_state *, pic_func_t f, int n, ...);
 pic_value pic_vlambda(pic_state *, pic_func_t f, int n, va_list);
@@ -257,6 +248,13 @@ pic_value pic_applyk(pic_state *, pic_value proc, int n, pic_value *argv);
  * port
  */
 
+typedef struct {
+  int (*read)(pic_state *, void *, char *, int);
+  int (*write)(pic_state *, void *, const char *, int);
+  long (*seek)(pic_state *, void *, long, int);
+  int (*close)(pic_state *, void *);
+} pic_port_type;
+
 #define PIC_SEEK_CUR 0
 #define PIC_SEEK_END 1
 #define PIC_SEEK_SET 2
@@ -303,6 +301,7 @@ PIC_NORETURN void pic_error(pic_state *, const char *msg, int n, ...);
 PIC_NORETURN void pic_raise(pic_state *, pic_value v);
 pic_value pic_make_error(pic_state *, const char *type, const char *msg, pic_value irrs); /* deprecated */
 pic_value pic_get_backtrace(pic_state *); /* deprecated */
+void pic_warnf(pic_state *pic, const char *fmt, ...); /* deprecated */
 #define pic_try pic_try_(PIC_GENSYM(cont), PIC_GENSYM(jmp))
 #define pic_try_(cont, jmp)                                             \
   do {                                                                  \
diff --git a/lib/value.h b/lib/include/picrin/value.h
similarity index 55%
rename from lib/value.h
rename to lib/include/picrin/value.h
index 293aedf9..21aff3e3 100644
--- a/lib/value.h
+++ b/lib/include/picrin/value.h
@@ -9,58 +9,6 @@
 extern "C" {
 #endif
 
-#if 0
-#define pic_int pic_int_inline
-#define pic_float pic_float_inline
-#define pic_char pic_char_inline
-#define pic_int_value pic_int_value_inline
-#define pic_float_value pic_float_value_inline
-#define pic_char_value pic_char_value_inline
-#define obj_value obj_value_inline /* TODO */
-#define pic_nil_value pic_nil_value_inline
-#define pic_eof_object pic_eof_object_inline
-#define pic_true_value pic_true_value_inline
-#define pic_false_value pic_false_value_inline
-#define pic_undef_value pic_undef_value_inline
-#define pic_invalid_value pic_invalid_value_inline
-#define pic_bool_value pic_bool_value_inline
-#define pic_invalid_p pic_invalid_p_inline
-#define pic_float_p pic_float_p_inline
-#define pic_int_p pic_int_p_inline
-#define pic_char_p pic_char_p_inline
-#define pic_eof_p pic_eof_p_inline
-#define pic_undef_p pic_undef_p_inline
-#define pic_true_p pic_true_p_inline
-#define pic_nil_p pic_nil_p_inline
-#define pic_false_p pic_false_p_inline
-#define pic_bool_p pic_bool_p_inline
-#define pic_str_p pic_str_p_inline
-#define pic_vec_p pic_vec_p_inline
-#define pic_blob_p pic_blob_p_inline
-#define pic_error_p pic_error_p_inline
-#define pic_id_p pic_id_p_inline
-#define pic_dict_p pic_dict_p_inline
-#define pic_weak_p pic_weak_p_inline
-#define pic_env_p pic_env_p_inline
-#define pic_rec_p pic_rec_p_inline
-#define pic_sym_p pic_sym_p_inline
-#define pic_pair_p pic_pair_p_inline
-#define pic_cp_p pic_cp_p_inline
-#define pic_func_p pic_func_p_inline
-#define pic_irep_p pic_irep_p_inline
-#define pic_proc_p pic_proc_p_inline
-#endif
-
-/* #ifndef INLINE */
-/* # if GENERATE_EXTERNAL_DEFINITION */
-/* #  define INLINE PIC_EXTERN_INLINE */
-/* # else */
-/* #  define INLINE PIC_INLINE */
-/* # endif */
-/* #endif */
-
-#define INLINE PIC_STATIC_INLINE
-
 enum {
   PIC_TYPE_INVALID = 1,
   PIC_TYPE_FLOAT   = 2,
@@ -92,12 +40,10 @@ enum {
   PIC_TYPE_IREP    = 33
 };
 
-PIC_STATIC_INLINE int obj_tt(void *); /* defined in object.h */
-
 #if !PIC_NAN_BOXING
 
 PIC_STATIC_INLINE pic_value
-make_value(int type)
+pic_make_value(int type)
 {
   pic_value v;
   v.type = type;
@@ -105,70 +51,50 @@ make_value(int type)
   return v;
 }
 
-PIC_STATIC_INLINE struct object *
-obj_ptr(pic_value v)
-{
-  return (struct object *)(v.u.data);
-}
-
-PIC_STATIC_INLINE bool
-obj_p(pic_state *PIC_UNUSED(pic), pic_value v)
-{
-  return v.type > PIC_IVAL_END;
-}
-
-PIC_STATIC_INLINE pic_value
-obj_value(void *ptr)
-{
-  pic_value v = make_value(obj_tt(ptr));
-  v.u.data = ptr;
-  return v;
-}
-
 PIC_STATIC_INLINE int
-value_type(pic_state *PIC_UNUSED(pic), pic_value v)
+pic_type(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return (int)(v.type);
 }
 
-INLINE int
+PIC_STATIC_INLINE int
 pic_int(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return v.u.i;
 }
 
-INLINE double
+PIC_STATIC_INLINE double
 pic_float(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return v.u.f;
 }
 
-INLINE char
+PIC_STATIC_INLINE char
 pic_char(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return v.u.c;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_int_value(pic_state *PIC_UNUSED(pic), int i)
 {
-  pic_value v = make_value(PIC_TYPE_INT);
+  pic_value v = pic_make_value(PIC_TYPE_INT);
   v.u.i = i;
   return v;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_float_value(pic_state *PIC_UNUSED(pic), double f)
 {
-  pic_value v = make_value(PIC_TYPE_FLOAT);
+  pic_value v = pic_make_value(PIC_TYPE_FLOAT);
   v.u.f = f;
   return v;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_char_value(pic_state *PIC_UNUSED(pic), char c)
 {
-  pic_value v = make_value(PIC_TYPE_CHAR);
+  pic_value v = pic_make_value(PIC_TYPE_CHAR);
   v.u.c = c;
   return v;
 }
@@ -184,40 +110,20 @@ pic_char_value(pic_state *PIC_UNUSED(pic), char c)
  */
 
 PIC_STATIC_INLINE pic_value
-make_value(int type)
+pic_make_value(int type)
 {
   pic_value v;
   v.v = 0xfff0000000000000ul | ((uint64_t)(type) << 46);
   return v;
 }
 
-PIC_STATIC_INLINE struct object *
-obj_ptr(pic_value v)
-{
-  return (struct object *)((0x3ffffffffffful & v.v) << 2);
-}
-
-PIC_STATIC_INLINE bool
-obj_p(pic_state *PIC_UNUSED(pic), pic_value v)
-{
-  return v.v > ((0x3ffC0ul + (0x3f & PIC_IVAL_END)) << 46);
-}
-
-PIC_STATIC_INLINE pic_value
-obj_value(void *ptr)
-{
-  pic_value v = make_value(obj_tt(ptr));
-  v.v |= 0x3ffffffffffful & ((uint64_t)ptr >> 2);
-  return v;
-}
-
 PIC_STATIC_INLINE int
-value_type(pic_state *PIC_UNUSED(pic), pic_value v)
+pic_type(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return 0xfff0000000000000ul >= v.v ? PIC_TYPE_FLOAT : ((v.v >> 46) & 0x3f);
 }
 
-INLINE int
+PIC_STATIC_INLINE int
 pic_int(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   union { int i; unsigned u; } u;
@@ -225,7 +131,7 @@ pic_int(pic_state *PIC_UNUSED(pic), pic_value v)
   return u.i;
 }
 
-INLINE double
+PIC_STATIC_INLINE double
 pic_float(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   union { double f; uint64_t i; } u;
@@ -233,21 +139,21 @@ pic_float(pic_state *PIC_UNUSED(pic), pic_value v)
   return u.f;
 }
 
-INLINE char
+PIC_STATIC_INLINE char
 pic_char(pic_state *PIC_UNUSED(pic), pic_value v)
 {
   return v.v & 0xfffffffful;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_int_value(pic_state *PIC_UNUSED(pic), int i)
 {
-  pic_value v = make_value(PIC_TYPE_INT);
+  pic_value v = pic_make_value(PIC_TYPE_INT);
   v.v |= (unsigned)i;
   return v;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_float_value(pic_state *PIC_UNUSED(pic), double f)
 {
   union { double f; uint64_t i; } u;
@@ -262,19 +168,19 @@ pic_float_value(pic_state *PIC_UNUSED(pic), double f)
   return v;
 }
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_char_value(pic_state *PIC_UNUSED(pic), char c)
 {
-  pic_value v = make_value(PIC_TYPE_CHAR);
+  pic_value v = pic_make_value(PIC_TYPE_CHAR);
   v.v |= (unsigned char)c;
   return v;
 }
 
 #endif  /* NAN_BOXING end */
 
-#define DEFVAL(name, type)                              \
-  INLINE pic_value name(pic_state *PIC_UNUSED(pic)) {   \
-    return make_value(type);                            \
+#define DEFVAL(name, type)                                              \
+  PIC_STATIC_INLINE pic_value name(pic_state *PIC_UNUSED(pic)) {        \
+    return pic_make_value(type);                                        \
   }
 
 DEFVAL(pic_nil_value, PIC_TYPE_NIL)
@@ -284,15 +190,15 @@ DEFVAL(pic_false_value, PIC_TYPE_FALSE)
 DEFVAL(pic_undef_value, PIC_TYPE_UNDEF)
 DEFVAL(pic_invalid_value, PIC_TYPE_INVALID)
 
-INLINE pic_value
+PIC_STATIC_INLINE pic_value
 pic_bool_value(pic_state *PIC_UNUSED(pic), bool b)
 {
-  return make_value(b ? PIC_TYPE_TRUE : PIC_TYPE_FALSE);
+  return pic_make_value(b ? PIC_TYPE_TRUE : PIC_TYPE_FALSE);
 }
 
-#define DEFPRED(name, type)                             \
-  INLINE bool name(pic_state *pic, pic_value obj) {     \
-    return value_type(pic, obj) == type;                \
+#define DEFPRED(name, type)                                     \
+  PIC_STATIC_INLINE bool name(pic_state *pic, pic_value obj) {  \
+    return pic_type(pic, obj) == type;                          \
   }
 
 DEFPRED(pic_invalid_p, PIC_TYPE_INVALID)
@@ -318,22 +224,22 @@ DEFPRED(pic_cp_p, PIC_TYPE_CP)
 DEFPRED(pic_func_p, PIC_TYPE_FUNC)
 DEFPRED(pic_irep_p, PIC_TYPE_IREP)
 
-INLINE bool
+PIC_STATIC_INLINE bool
 pic_bool_p(pic_state *pic, pic_value obj)
 {
   return pic_true_p(pic, obj) || pic_false_p(pic, obj);
 }
 
-INLINE bool
+PIC_STATIC_INLINE bool
 pic_proc_p(pic_state *pic, pic_value o)
 {
   return pic_func_p(pic, o) || pic_irep_p(pic, o);
 }
 
-INLINE bool
+PIC_STATIC_INLINE bool
 pic_id_p(pic_state *pic, pic_value o)
 {
-  return value_type(pic, o) == PIC_TYPE_ID || pic_sym_p(pic, o);
+  return pic_type(pic, o) == PIC_TYPE_ID || pic_sym_p(pic, o);
 }
 
 #if defined(__cplusplus)
diff --git a/lib/number.c b/lib/number.c
index a3e8b031..3578d9ea 100644
--- a/lib/number.c
+++ b/lib/number.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 static pic_value
diff --git a/lib/object.h b/lib/object.h
index 5ba130f2..133ff6a9 100644
--- a/lib/object.h
+++ b/lib/object.h
@@ -188,12 +188,56 @@ struct checkpoint {
     if (tolen - at < e - s) pic_error(pic, "invalid range", 0);        \
   } while (0)
 
-PIC_STATIC_INLINE struct object *obj_ptr(pic_value); /* defined in value.h */
-
 PIC_STATIC_INLINE int obj_tt(void *ptr) {
   return ((struct basic *)ptr)->tt;
 }
 
+#if !PIC_NAN_BOXING
+
+PIC_STATIC_INLINE struct object *
+obj_ptr(pic_value v)
+{
+  return (struct object *)(v.u.data);
+}
+
+PIC_STATIC_INLINE bool
+obj_p(pic_state *PIC_UNUSED(pic), pic_value v)
+{
+  return v.type > PIC_IVAL_END;
+}
+
+PIC_STATIC_INLINE pic_value
+obj_value(void *ptr)
+{
+  pic_value v = pic_make_value(obj_tt(ptr));
+  v.u.data = ptr;
+  return v;
+}
+
+#else  /* NAN_BOXING */
+
+PIC_STATIC_INLINE struct object *
+obj_ptr(pic_value v)
+{
+  return (struct object *)((0x3ffffffffffful & v.v) << 2);
+}
+
+PIC_STATIC_INLINE bool
+obj_p(pic_state *PIC_UNUSED(pic), pic_value v)
+{
+  return v.v > ((0x3ffC0ul + (0x3f & PIC_IVAL_END)) << 46);
+}
+
+PIC_STATIC_INLINE pic_value
+obj_value(void *ptr)
+{
+  pic_value v = pic_make_value(obj_tt(ptr));
+  v.v |= 0x3ffffffffffful & ((uint64_t)ptr >> 2);
+  return v;
+}
+
+#endif  /* NAN_BOXING */
+
 #define DEFPTR(name,type)                                               \
   PIC_STATIC_INLINE type *name(pic_state *PIC_UNUSED(pic), pic_value o) { \
     return (type *) obj_ptr(o);                                         \
diff --git a/lib/pair.c b/lib/pair.c
index 9d288b4c..a2070176 100644
--- a/lib/pair.c
+++ b/lib/pair.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 pic_value
diff --git a/lib/port.c b/lib/port.c
index 49b0f24e..bb81640c 100644
--- a/lib/port.c
+++ b/lib/port.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
@@ -14,7 +13,7 @@
 bool
 pic_port_p(pic_state *pic, pic_value obj, const pic_port_type *type)
 {
-  if (value_type(pic, obj) != PIC_TYPE_PORT) {
+  if (pic_type(pic, obj) != PIC_TYPE_PORT) {
     return false;
   }
   return type == NULL || pic_port_ptr(pic, obj)->file.vtable == type;
diff --git a/lib/proc.c b/lib/proc.c
index b591140b..93607c15 100644
--- a/lib/proc.c
+++ b/lib/proc.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 #include "vm.h"
@@ -189,7 +188,7 @@ pic_get_args(pic_state *pic, const char *format, ...)
         e = (c == c2 ? va_arg(ap, bool *) : &dummy);                    \
                                                                         \
         v = GET_ARG(pic, i);                                            \
-        switch (value_type(pic, v)) {                                   \
+        switch (pic_type(pic, v)) {                                     \
         case PIC_TYPE_FLOAT:                                            \
           *n = pic_float(pic, v);                                       \
           *e = false;                                                   \
diff --git a/lib/record.c b/lib/record.c
index 299eca16..a8b8d1a9 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 pic_value
diff --git a/lib/state.c b/lib/state.c
index 6b994f68..ebfe4661 100644
--- a/lib/state.c
+++ b/lib/state.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/string.c b/lib/string.c
index 7e81fbf2..872d4239 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 struct rope {
diff --git a/lib/symbol.c b/lib/symbol.c
index 8f37e41b..4af7d36e 100644
--- a/lib/symbol.c
+++ b/lib/symbol.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/var.c b/lib/var.c
index b36b7a38..7d392cd7 100644
--- a/lib/var.c
+++ b/lib/var.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 #include "state.h"
 
diff --git a/lib/vector.c b/lib/vector.c
index 2c42d673..b1602ebf 100644
--- a/lib/vector.c
+++ b/lib/vector.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 pic_value
diff --git a/lib/weak.c b/lib/weak.c
index cfdfd739..7d7ec2fc 100644
--- a/lib/weak.c
+++ b/lib/weak.c
@@ -3,7 +3,6 @@
  */
 
 #include "picrin.h"
-#include "value.h"
 #include "object.h"
 
 KHASH_DEFINE(weak, struct object *, pic_value, kh_ptr_hash_func, kh_ptr_hash_equal)