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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?.

[ GitHub ] 

  


# File 'object.c', line 1653



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 1605



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 1489



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 1640



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


  








  

    #inspect  ⇒ "nil"   



  

    

Always returns the string “nil”.


  



  [ GitHub ]


  

  


# File 'object.c', line 1476



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.


  



  [ GitHub ]


  

  


# File 'rational.c', line 2134



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


  








  

    #to_a  ⇒ Array   



  

    

Always returns an empty array.



nil.to_a   #=> []


  



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# File 'object.c', line 1446



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 1569



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


  








  

    #to_f  ⇒ 0.0   



  

    

Always returns zero.



nil.to_f   #=> 0.0


  



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# File 'object.c', line 1416



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 1463



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


  








  

    #to_i  ⇒ 0   



  

    

Always returns zero.



nil.to_i   #=> 0


  



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# File 'object.c', line 1401



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


  








  

    #to_r  ⇒ 1   



  

    

Returns zero as a rational.


  



  [ GitHub ]


  

  


# File 'rational.c', line 2121



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


  








  

    #to_s  ⇒ ""   



  

    

Always returns the empty string.


  



  [ GitHub ]


  

  


# File 'object.c', line 1429



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 1621



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