Method: Object#remove_instance_variable

Defined in:
object.c

#remove_instance_variable(symbol) ⇒ Object

Removes the named instance variable from obj, returning that variable's value.

class Dummy
  attr_reader :var
  def initialize
    @var = 99
  end
  def remove
    remove_instance_variable(:@var)
  end
end
d = Dummy.new
d.var      #=> 99
d.remove   #=> 99
d.var      #=> nil

Returns:



# File 'object.c'

/*
 *  call-seq:
 *     obj.remove_instance_variable(symbol)    -> obj
 *
 *  Removes the named instance variable from <i>obj</i>, returning that
 *  variable's value.
 *
 *     class Dummy
 *       attr_reader :var
 *       def initialize
 *         @var = 99
 *       end
 *       def remove
 *         remove_instance_variable(:@var)
 *       end
 *     end
 *     d = Dummy.new
 *     d.var      #=> 99
 *     d.remove   #=> 99
 *     d.var      #=> nil
 */

VALUE
rb_obj_remove_instance_variable(VALUE obj, VALUE name)
{
    VALUE val = Qnil;
    const ID id = rb_to_id(name);
    st_data_t n, v;
    struct st_table *iv_index_tbl;
    st_data_t index;

    if (!OBJ_UNTRUSTED(obj) && rb_safe_level() >= 4)
	rb_raise(rb_eSecurityError, "Insecure: can't modify instance variable");
    if (OBJ_FROZEN(obj)) rb_error_frozen("object");
    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
    }

    switch (TYPE(obj)) {
      case T_OBJECT:
        iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
        if (!iv_index_tbl) break;
        if (!st_lookup(iv_index_tbl, (st_data_t)id, &index)) break;
        if (ROBJECT_NUMIV(obj) <= (long)index) break;
        val = ROBJECT_IVPTR(obj)[index];
        if (val != Qundef) {
            ROBJECT_IVPTR(obj)[index] = Qundef;
            return val;
        }
	break;
      case T_CLASS:
      case T_MODULE:
	n = id;
	if (RCLASS_IV_TBL(obj) && st_delete(RCLASS_IV_TBL(obj), &n, &v)) {
	    return (VALUE)v;
	}
	break;
      default:
	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
	    v = val;
	    if (generic_ivar_remove(obj, (st_data_t)id, &v)) {
		return (VALUE)v;
	    }
	}
	break;
    }
    rb_name_error(id, "instance variable %s not defined", rb_id2name(id));
    return Qnil;		/* not reached */
}