Class: NilClass

Inherits:
Object show all
Defined in:
object.c,
object.c

Overview

The class of the singleton object nil.

Instance Method Summary collapse

Instance Method Details

#&(obj) ⇒ false #&(obj) ⇒ false

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:

  • #&(obj) ⇒ false

    Returns:

    • (false)
  • #&(obj) ⇒ false

    Returns:

    • (false)

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# File 'object.c', line 1555

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

#===(other) ⇒ Boolean

Case Equality – For class Object, effectively the same as calling #==, but typically overridden by descendants to provide meaningful semantics in case statements.

Returns:

  • (Boolean)

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# File 'object.c', line 144

VALUE
rb_equal(VALUE obj1, VALUE obj2)
{
    VALUE result;

    if (obj1 == obj2) return Qtrue;
    result = rb_equal_opt(obj1, obj2);
    if (result == Qundef) {
  result = rb_funcall(obj1, id_eq, 1, obj2);
    }
    if (RTEST(result)) return Qtrue;
    return Qfalse;
}

#=~(other) ⇒ nil

Dummy pattern matching – always returns nil.

Returns:

  • (nil)

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# File 'object.c', line 1439

static VALUE
nil_match(VALUE obj1, VALUE obj2)
{
    return Qnil;
}

#^(obj) ⇒ Boolean #^(obj) ⇒ Boolean

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

Overloads:

  • #^(obj) ⇒ Boolean

    Returns:

    • (Boolean)
  • #^(obj) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'object.c', line 1590

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

#inspectObject

Always returns the string “nil”.


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# File 'object.c', line 1426

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

#nil?true

Only the object nil responds true to nil?.

Returns:

  • (true)

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# File 'object.c', line 1603

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

#rationalize([eps]) ⇒ Object

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


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# File 'rational.c', line 2145

static VALUE
nilclass_rationalize(int argc, VALUE *argv, VALUE self)
{
    rb_check_arity(argc, 0, 1);
    return nilclass_to_r(self);
}

#to_aObject

call-seq:

   nil.to_a    -> []

Always returns an empty array.

   nil.to_a   #=> []

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# File 'object.c', line 1396

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

#to_cObject

Returns zero as a complex.


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# File 'complex.c', line 1695

static VALUE
nilclass_to_c(VALUE self)
{
    return rb_complex_new1(INT2FIX(0));
}

#to_f0.0

Always returns zero.

nil.to_f   #=> 0.0

Returns:

  • (0.0)

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# File 'object.c', line 1366

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

#to_hObject

call-seq:

   nil.to_h    -> {}

Always returns an empty hash.

   nil.to_h   #=> {}

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# File 'object.c', line 1413

static VALUE
nil_to_h(VALUE obj)
{
    return rb_hash_new();
}

#to_i0

Always returns zero.

nil.to_i   #=> 0

Returns:

  • (0)

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# File 'object.c', line 1351

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

#to_rObject

Returns zero as a rational.


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# File 'rational.c', line 2132

static VALUE
nilclass_to_r(VALUE self)
{
    return rb_rational_new1(INT2FIX(0));
}

#to_sObject

Always returns the empty string.


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# File 'object.c', line 1379

static VALUE
nil_to_s(VALUE obj)
{
    return rb_cNilClass_to_s;
}

#|(obj) ⇒ Boolean #|(obj) ⇒ Boolean

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

Overloads:

  • #|(obj) ⇒ Boolean

    Returns:

    • (Boolean)
  • #|(obj) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'object.c', line 1571

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