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class NilClass

Parent:
Object

The class of the singleton object nil.

Public Instance Methods

false & obj → false Show source
nil & obj → false 
static VALUE
false_and(VALUE obj, VALUE obj2)
{
    return Qfalse;
}

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.

obj === other → true or false Show source 
VALUE
rb_equal(VALUE obj1, VALUE obj2)
{
    VALUE result;

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

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

false ^ obj → true or false Show source
nil ^ obj → true or false 
static VALUE
false_xor(VALUE obj, VALUE obj2)
{
    return RTEST(obj2)?Qtrue:Qfalse;
}

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

inspect → "nil" Show source 
static VALUE
nil_inspect(VALUE obj)
{
    return rb_usascii_str_new2("nil");
}

Always returns the string “nil”.

nil? → true Show source 
static VALUE
rb_true(VALUE obj)
{
    return Qtrue;
}

Only the object nil responds true to nil?.

rationalize([eps]) → (0/1) Show source 
static VALUE
nilclass_rationalize(int argc, VALUE *argv, VALUE self)
{
    rb_scan_args(argc, argv, "01", NULL);
    return nilclass_to_r(self);
}

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

to_a → [] Show source 
static VALUE
nil_to_a(VALUE obj)
{
    return rb_ary_new2(0);
}

Always returns an empty array.

nil.to_a   #=> []
to_c → (0+0i) Show source 
static VALUE
nilclass_to_c(VALUE self)
{
    return rb_complex_new1(INT2FIX(0));
}

Returns zero as a complex.

to_f → 0.0 Show source 
static VALUE
nil_to_f(VALUE obj)
{
    return DBL2NUM(0.0);
}

Always returns zero.

nil.to_f   #=> 0.0
to_h → {} Show source 
static VALUE
nil_to_h(VALUE obj)
{
    return rb_hash_new();
}

Always returns an empty hash.

nil.to_h   #=> {}
to_i → 0 Show source 
static VALUE
nil_to_i(VALUE obj)
{
    return INT2FIX(0);
}

Always returns zero.

nil.to_i   #=> 0
to_r → (0/1) Show source 
static VALUE
nilclass_to_r(VALUE self)
{
    return rb_rational_new1(INT2FIX(0));
}

Returns zero as a rational.

to_s → "" Show source 
static VALUE
nil_to_s(VALUE obj)
{
    return rb_usascii_str_new(0, 0);
}

Always returns the empty string.

false | obj → true or false Show source
nil | obj → true or false 
static VALUE
false_or(VALUE obj, VALUE obj2)
{
    return RTEST(obj2)?Qtrue:Qfalse;
}

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

Ruby Core © 1993–2017 Yukihiro Matsumoto
Licensed under the Ruby License.
Ruby Standard Library © contributors
Licensed under their own licenses.