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Class: NilClass

Relationships & Source Files
Inherits: Object
Defined in: object.c,
complex.c,
object.c,
rational.c

Overview

The class of the singleton object nil.

Instance Attribute Summary

Instance Method Summary

Instance Attribute Details

#nil?Boolean (readonly)

Only the object nil responds true to nil?.

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# File 'object.c', line 1650

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

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.

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# File 'object.c', line 1602

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

#===(other) ⇒ Boolean

Alias for Object#===.

#=~(other) ⇒ nil

Dummy pattern matching – always returns nil.

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# File 'object.c', line 1486

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.

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# File 'object.c', line 1637

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

#inspect ⇒ "nil"

Always returns the string “nil”.

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# File 'object.c', line 1473

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

#rationalize([eps]) ⇒ 1

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

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# File 'rational.c', line 2122

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

#to_aArray

Always returns an empty array.

nil.to_a   #=> []
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# File 'object.c', line 1443

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

#to_c ⇒ (0+0i)

Returns zero as a complex.

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# File 'complex.c', line 1572

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

#to_f0.0

Always returns zero.

nil.to_f   #=> 0.0
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# File 'object.c', line 1413

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

#to_h ⇒ {}

Always returns an empty hash.

nil.to_h   #=> {}
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# File 'object.c', line 1460

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

#to_i0

Always returns zero.

nil.to_i   #=> 0
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# File 'object.c', line 1398

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

#to_r1

Returns zero as a rational.

[ GitHub ]

  
# File 'rational.c', line 2109

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

#to_s ⇒ ""

Always returns the empty string.

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# File 'object.c', line 1426

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

#|(obj) ⇒ Boolean #|(obj) ⇒ Boolean

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

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# File 'object.c', line 1618

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