diff --git a/include/picrin/value.h b/include/picrin/value.h
index ac9afeed..6b670bd8 100644
--- a/include/picrin/value.h
+++ b/include/picrin/value.h
@@ -140,8 +140,8 @@ struct pic_blob;
 #define pic_str_ptr(o) ((struct pic_string *)pic_ptr(o))
 #define pic_vec_ptr(o) ((struct pic_vector *)pic_ptr(o))
 
-enum pic_tt pic_type(pic_value);
-const char *pic_type_repr(enum pic_tt);
+inline enum pic_tt pic_type(pic_value);
+inline const char *pic_type_repr(enum pic_tt);
 
 inline pic_value pic_nil_value();
 inline pic_value pic_true_value();
@@ -175,10 +175,90 @@ inline pic_value pic_none_value();
 /* obsoleted macro(s) */
 #define pic_symbol_p pic_sym_p
 
-bool pic_eq_p(pic_value, pic_value);
-bool pic_eqv_p(pic_value, pic_value);
+inline bool pic_eq_p(pic_value, pic_value);
+inline bool pic_eqv_p(pic_value, pic_value);
 
 
+inline enum pic_tt
+pic_type(pic_value v)
+{
+  switch (pic_vtype(v)) {
+  case PIC_VTYPE_NIL:
+    return PIC_TT_NIL;
+  case PIC_VTYPE_TRUE:
+    return PIC_TT_BOOL;
+  case PIC_VTYPE_FALSE:
+    return PIC_TT_BOOL;
+  case PIC_VTYPE_UNDEF:
+    return PIC_TT_UNDEF;
+  case PIC_VTYPE_FLOAT:
+    return PIC_TT_FLOAT;
+  case PIC_VTYPE_INT:
+    return PIC_TT_INT;
+  case PIC_VTYPE_SYMBOL:
+    return PIC_TT_SYMBOL;
+  case PIC_VTYPE_CHAR:
+    return PIC_TT_CHAR;
+  case PIC_VTYPE_EOF:
+    return PIC_TT_EOF;
+  case PIC_VTYPE_HEAP:
+    return ((struct pic_object *)pic_ptr(v))->tt;
+  }
+}
+
+inline const char *
+pic_type_repr(enum pic_tt tt)
+{
+  switch (tt) {
+  case PIC_TT_NIL:
+    return "nil";
+  case PIC_TT_BOOL:
+    return "boolean";
+  case PIC_TT_FLOAT:
+    return "float";
+  case PIC_TT_INT:
+    return "int";
+  case PIC_TT_SYMBOL:
+    return "symbol";
+  case PIC_TT_CHAR:
+    return "char";
+  case PIC_TT_EOF:
+    return "eof";
+  case PIC_TT_UNDEF:
+    return "undef";
+  case PIC_TT_PAIR:
+    return "pair";
+  case PIC_TT_STRING:
+    return "string";
+  case PIC_TT_VECTOR:
+    return "vector";
+  case PIC_TT_BLOB:
+    return "blob";
+  case PIC_TT_PORT:
+    return "port";
+  case PIC_TT_ERROR:
+    return "error";
+  case PIC_TT_ENV:
+    return "env";
+  case PIC_TT_CONT:
+    return "cont";
+  case PIC_TT_PROC:
+    return "proc";
+  case PIC_TT_SC:
+    return "sc";
+  case PIC_TT_SENV:
+    return "senv";
+  case PIC_TT_SYNTAX:
+    return "syntax";
+  case PIC_TT_LIB:
+    return "lib";
+  case PIC_TT_VAR:
+    return "var";
+  case PIC_TT_IREP:
+    return "irep";
+  }
+}
+
 inline pic_value
 pic_nil_value()
 {
@@ -314,6 +394,60 @@ pic_none_value()
 #endif
 }
 
+#if PIC_NAN_BOXING
+
+inline bool
+pic_eq_p(pic_value x, pic_value y)
+{
+  return x.u.data == y.u.data;
+}
+
+inline bool
+pic_eqv_p(pic_value x, pic_value y)
+{
+  return x.u.data == y.u.data;
+}
+
+#else
+
+inline bool
+pic_eq_p(pic_value x, pic_value y)
+{
+  if (pic_type(x) != pic_type(y))
+    return false;
+
+  switch (pic_type(x)) {
+  case PIC_TT_NIL:
+    return true;
+  case PIC_TT_SYMBOL:
+    return pic_sym(x) == pic_sym(y);
+  default:
+    return pic_ptr(x) == pic_ptr(y);
+  }
+}
+
+inline bool
+pic_eqv_p(pic_value x, pic_value y)
+{
+  if (pic_type(x) != pic_type(y))
+    return false;
+
+  switch (pic_type(x)) {
+  case PIC_TT_NIL:
+    return true;
+  case PIC_TT_SYMBOL:
+    return pic_sym(x) == pic_sym(y);
+  case PIC_TT_FLOAT:
+    return pic_float(x) == pic_float(y);
+  case PIC_TT_INT:
+    return pic_int(x) == pic_int(y);
+  default:
+    return pic_ptr(x) == pic_ptr(y);
+  }
+}
+
+#endif
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/src/value.c b/src/value.c
index b3dc459b..8b749a0e 100644
--- a/src/value.c
+++ b/src/value.c
@@ -7,140 +7,3 @@
 
 #include "picrin.h"
 
-enum pic_tt
-pic_type(pic_value v)
-{
-  switch (pic_vtype(v)) {
-  case PIC_VTYPE_NIL:
-    return PIC_TT_NIL;
-  case PIC_VTYPE_TRUE:
-    return PIC_TT_BOOL;
-  case PIC_VTYPE_FALSE:
-    return PIC_TT_BOOL;
-  case PIC_VTYPE_UNDEF:
-    return PIC_TT_UNDEF;
-  case PIC_VTYPE_FLOAT:
-    return PIC_TT_FLOAT;
-  case PIC_VTYPE_INT:
-    return PIC_TT_INT;
-  case PIC_VTYPE_SYMBOL:
-    return PIC_TT_SYMBOL;
-  case PIC_VTYPE_CHAR:
-    return PIC_TT_CHAR;
-  case PIC_VTYPE_EOF:
-    return PIC_TT_EOF;
-  case PIC_VTYPE_HEAP:
-    return ((struct pic_object *)pic_ptr(v))->tt;
-  }
-  /* logic flaw (suppress warnings gcc will emit) */
-  abort();
-}
-
-const char *
-pic_type_repr(enum pic_tt tt)
-{
-  switch (tt) {
-  case PIC_TT_NIL:
-    return "nil";
-  case PIC_TT_BOOL:
-    return "boolean";
-  case PIC_TT_FLOAT:
-    return "float";
-  case PIC_TT_INT:
-    return "int";
-  case PIC_TT_SYMBOL:
-    return "symbol";
-  case PIC_TT_CHAR:
-    return "char";
-  case PIC_TT_EOF:
-    return "eof";
-  case PIC_TT_UNDEF:
-    return "undef";
-  case PIC_TT_PAIR:
-    return "pair";
-  case PIC_TT_STRING:
-    return "string";
-  case PIC_TT_VECTOR:
-    return "vector";
-  case PIC_TT_BLOB:
-    return "blob";
-  case PIC_TT_PORT:
-    return "port";
-  case PIC_TT_ERROR:
-    return "error";
-  case PIC_TT_ENV:
-    return "env";
-  case PIC_TT_CONT:
-    return "cont";
-  case PIC_TT_PROC:
-    return "proc";
-  case PIC_TT_SC:
-    return "sc";
-  case PIC_TT_SENV:
-    return "senv";
-  case PIC_TT_SYNTAX:
-    return "syntax";
-  case PIC_TT_LIB:
-    return "lib";
-  case PIC_TT_VAR:
-    return "var";
-  case PIC_TT_IREP:
-    return "irep";
-  }
-  /* logic flaw */
-  abort();
-}
-
-#if PIC_NAN_BOXING
-
-bool
-pic_eq_p(pic_value x, pic_value y)
-{
-  return x.u.data == y.u.data;
-}
-
-bool
-pic_eqv_p(pic_value x, pic_value y)
-{
-  return x.u.data == y.u.data;
-}
-
-#else
-
-bool
-pic_eq_p(pic_value x, pic_value y)
-{
-  if (pic_type(x) != pic_type(y))
-    return false;
-
-  switch (pic_type(x)) {
-  case PIC_TT_NIL:
-    return true;
-  case PIC_TT_SYMBOL:
-    return pic_sym(x) == pic_sym(y);
-  default:
-    return pic_ptr(x) == pic_ptr(y);
-  }
-}
-
-bool
-pic_eqv_p(pic_value x, pic_value y)
-{
-  if (pic_type(x) != pic_type(y))
-    return false;
-
-  switch (pic_type(x)) {
-  case PIC_TT_NIL:
-    return true;
-  case PIC_TT_SYMBOL:
-    return pic_sym(x) == pic_sym(y);
-  case PIC_TT_FLOAT:
-    return pic_float(x) == pic_float(y);
-  case PIC_TT_INT:
-    return pic_int(x) == pic_int(y);
-  default:
-    return pic_ptr(x) == pic_ptr(y);
-  }
-}
-
-#endif