to_str

static VALUE
name_err_mesg_to_str(VALUE obj)
{
    VALUE *ptr, mesg;
    TypedData_Get_Struct(obj, VALUE, &name_err_mesg_data_type, ptr);

    mesg = ptr[NAME_ERR_MESG__MESG];
    if (NIL_P(mesg)) return Qnil;
    else {
        struct RString s_str, d_str;
        VALUE c, s, d = 0, args[4];
        int state = 0, singleton = 0;
        rb_encoding *usascii = rb_usascii_encoding();

#define FAKE_CSTR(v, str) rb_setup_fake_str((v), (str), rb_strlen_lit(str), usascii)
        obj = ptr[NAME_ERR_MESG__RECV];
        switch (obj) {
          case Qnil:
            d = FAKE_CSTR(&d_str, "nil");
            break;
          case Qtrue:
            d = FAKE_CSTR(&d_str, "true");
            break;
          case Qfalse:
            d = FAKE_CSTR(&d_str, "false");
            break;
          default:
            d = rb_protect(rb_inspect, obj, &state);
            if (state)
                rb_set_errinfo(Qnil);
            if (NIL_P(d) || RSTRING_LEN(d) > 65) {
                d = rb_any_to_s(obj);
            }
            singleton = (RSTRING_LEN(d) > 0 && RSTRING_PTR(d)[0] == '#');
            d = QUOTE(d);
            break;
        }
        if (!singleton) {
            s = FAKE_CSTR(&s_str, ":");
            c = rb_class_name(CLASS_OF(obj));
        }
        else {
            c = s = FAKE_CSTR(&s_str, "");
        }
        args[0] = QUOTE(rb_obj_as_string(ptr[NAME_ERR_MESG__NAME]));
        args[1] = d;
        args[2] = s;
        args[3] = c;
        mesg = rb_str_format(4, args, mesg);
    }
    return mesg;
}