add user-defined data type API

include/picrin/data.h

@@ -0,0 +1,33 @@
+/**
+ * See Copyright Notice in picrin.h
+ */
+
+#ifndef PICRIN_DATA_H__
+#define PICRIN_DATA_H__
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+typedef struct {
+  const char *type_name;
+  void (*dtor)(pic_state *, void *);
+} pic_data_type;
+
+struct pic_data {
+  PIC_OBJECT_HEADER;
+  const pic_data_type *type;
+  xhash storage;                /* const char * to pic_value table */
+  void *data;
+};
+
+#define pic_data_p(o) (pic_type(o) == PIC_TT_DATA)
+#define pic_data_ptr(o) ((struct pic_data *)pic_ptr(o))
+
+struct pic_data *pic_data_alloc(pic_state *, const pic_data_type *, void *);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif

include/picrin/value.h

@@ -114,7 +114,8 @@ enum pic_tt {
   PIC_TT_SC,
   PIC_TT_LIB,
   PIC_TT_VAR,
-  PIC_TT_IREP
+  PIC_TT_IREP,
+  PIC_TT_DATA
 };
 
 #define PIC_OBJECT_HEADER			\
@@ -258,6 +259,8 @@ pic_type_repr(enum pic_tt tt)
     return "var";
   case PIC_TT_IREP:
     return "irep";
+  case PIC_TT_DATA:
+    return "data";
   }
   return 0;                     /* logic flaw */
 }