Class: NilClass

Inherits:
Object show all
Defined in:
object.c

Overview

The class of the singleton object nil.

Instance Method Summary (collapse)

Instance Method Details

- (false) &(obj) - (false) &(obj)

And---Returns false. obj is always evaluated as it is the argument to a method call---there is no short-circuit evaluation in this case.

Overloads:

  • - (false) &(obj)

    Returns:

    • (false)
  • - (false) &(obj)

    Returns:

    • (false)


# File 'object.c'

/*
 *  call-seq:
 *     false & obj   -> false
 *     nil & obj     -> false
 *
 *  And---Returns <code>false</code>. <i>obj</i> is always
 *  evaluated as it is the argument to a method call---there is no
 *  short-circuit evaluation in this case.
 */

static VALUE
false_and(VALUE obj, VALUE obj2)
{
    return Qfalse;
}

- (Boolean) ^(obj) - (Boolean) ^(obj)

Exclusive Or---If obj is nil or false, returns false; otherwise, returns true.

Overloads:

  • - (Boolean) ^(obj)

    Returns:

    • (Boolean)
  • - (Boolean) ^(obj)

    Returns:

    • (Boolean)


# File 'object.c'

/*
 *  call-seq:
 *     false ^ obj    -> true or false
 *     nil   ^ obj    -> true or false
 *
 *  Exclusive Or---If <i>obj</i> is <code>nil</code> or
 *  <code>false</code>, returns <code>false</code>; otherwise, returns
 *  <code>true</code>.
 *
 */

static VALUE
false_xor(VALUE obj, VALUE obj2)
{
    return RTEST(obj2)?Qtrue:Qfalse;
}

- (Object) inspect

Always returns the string "nil".



# File 'object.c'

/*
 *  call-seq:
 *    nil.inspect  -> "nil"
 *
 *  Always returns the string "nil".
 */

static VALUE
nil_inspect(VALUE obj)
{
    return rb_usascii_str_new2("nil");
}

- (Object) nil?

call_seq:

nil.nil?               -> true

Only the object nil responds true to nil?.



# File 'object.c'

/*
 * call_seq:
 *   nil.nil?               -> true
 *
 * Only the object <i>nil</i> responds <code>true</code> to <code>nil?</code>.
 */

static VALUE
rb_true(VALUE obj)
{
    return Qtrue;
}

- (Object) rationalize([eps])

Returns zero as a rational. An optional argument eps is always ignored.



# File 'rational.c'

/*
 * call-seq:
 *    nil.rationalize([eps])  ->  (0/1)
 *
 * Returns zero as a rational.  An optional argument eps is always
 * ignored.
 */
static VALUE
nilclass_rationalize(int argc, VALUE *argv, VALUE self)
{
    rb_scan_args(argc, argv, "01", NULL);
    return nilclass_to_r(self);
}

- (Array) to_a

Always returns an empty array.

nil.to_a   #=> []

Returns:



# File 'object.c'

/*
 * Document-method: to_a
 *
 *  call-seq:
 *     nil.to_a    -> []
 *
 *  Always returns an empty array.
 *
 *     nil.to_a   #=> []
 */

static VALUE
nil_to_a(VALUE obj)
{
    return rb_ary_new2(0);
}

- (Object) to_c

Returns zero as a complex.



# File 'complex.c'

/*
 * call-seq:
 *    nil.to_c  ->  (0+0i)
 *
 * Returns zero as a complex.
 */
static VALUE
nilclass_to_c(VALUE self)
{
    return rb_complex_new1(INT2FIX(0));
}

- (0.0) to_f

Always returns zero.

nil.to_f   #=> 0.0

Returns:

  • (0.0)


# File 'object.c'

/*
 *  call-seq:
 *     nil.to_f    -> 0.0
 *
 *  Always returns zero.
 *
 *     nil.to_f   #=> 0.0
 */

static VALUE
nil_to_f(VALUE obj)
{
    return DBL2NUM(0.0);
}

- (0) to_i

Always returns zero.

nil.to_i   #=> 0

Returns:

  • (0)


# File 'object.c'

/*
 *  call-seq:
 *     nil.to_i -> 0
 *
 *  Always returns zero.
 *
 *     nil.to_i   #=> 0
 */


static VALUE
nil_to_i(VALUE obj)
{
    return INT2FIX(0);
}

- (Object) to_r

Returns zero as a rational.



# File 'rational.c'

/*
 * call-seq:
 *    nil.to_r  ->  (0/1)
 *
 * Returns zero as a rational.
 */
static VALUE
nilclass_to_r(VALUE self)
{
    return rb_rational_new1(INT2FIX(0));
}

- (Object) to_s

Always returns the empty string.



# File 'object.c'

/*
 *  call-seq:
 *     nil.to_s    -> ""
 *
 *  Always returns the empty string.
 */

static VALUE
nil_to_s(VALUE obj)
{
    return rb_usascii_str_new(0, 0);
}

- (Boolean) |(obj) - (Boolean) |(obj)

Or---Returns false if obj is nil or false; true otherwise.

Overloads:

  • - (Boolean) |(obj)

    Returns:

    • (Boolean)
  • - (Boolean) |(obj)

    Returns:

    • (Boolean)


# File 'object.c'

/*
 *  call-seq:
 *     false | obj   ->   true or false
 *     nil   | obj   ->   true or false
 *
 *  Or---Returns <code>false</code> if <i>obj</i> is
 *  <code>nil</code> or <code>false</code>; <code>true</code> otherwise.
 */

static VALUE
false_or(VALUE obj, VALUE obj2)
{
    return RTEST(obj2)?Qtrue:Qfalse;
}