Class: NilClass
Overview
The class of the singleton object nil.
Instance Method Summary (collapse)
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- (Object) &
And--Returns false.
-
- (Object) ^
Exclusive Or--If obj is nil or false, returns false; otherwise, returns true.
-
- (Object) inspect
Always returns the string “nil”.
-
- (Object) nil?
call_seq:.
-
- (Object) rationalize([eps])
Returns zero as a rational.
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- (Object) to_a
call-seq:.
-
- (Object) to_c
Returns zero as a complex.
-
- (0.0) to_f
Always returns zero.
-
- (0) to_i
Always returns zero.
-
- (Object) to_r
Returns zero as a rational.
-
- (Object) to_s
Always returns the empty string.
-
- (Object) |
Or--Returns false if obj is nil or false; true otherwise.
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.
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# 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;
}
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- (Boolean) ^(obj) - (Boolean) ^(obj)
Exclusive Or--If obj is nil or false, returns false; otherwise, returns true.
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# 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;
}
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- (Object) inspect
Always returns the string “nil”.
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# 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");
}
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- (Object) nil?
call_seq:
nil.nil? -> true
Only the object nil responds true to nil?.
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# 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;
}
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- (Object) rationalize([eps])
Returns zero as a rational. An optional argument eps is always ignored.
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# 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);
}
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- (Object) to_a
call-seq:
nil.to_a -> []
Always returns an empty array.
nil.to_a #=> []
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# 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);
}
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- (Object) to_c
Returns zero as a complex.
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# 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));
}
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- (0.0) to_f
Always returns zero.
nil.to_f #=> 0.0
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# 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);
}
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- (0) to_i
Always returns zero.
nil.to_i #=> 0
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# 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);
}
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- (Object) to_r
Returns zero as a rational.
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# 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));
}
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- (Object) to_s
Always returns the empty string.
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# 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);
}
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- (Boolean) |(obj) - (Boolean) |(obj)
Or--Returns false if obj is nil or false; true otherwise.
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# 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;
}
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