class NilClass
The class of the singleton object nil
.
Public Instance Methods
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.
static VALUE false_and(VALUE obj, VALUE obj2) { return Qfalse; }
Case Equality – For class Object
, effectively the same as calling #==
, but typically overridden by descendants to provide meaningful semantics in case
statements.
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; }
Dummy pattern matching – always returns nil.
static VALUE nil_match(VALUE obj1, VALUE obj2) { return Qnil; }
Exclusive Or—If obj is nil
or false
, returns false
; otherwise, returns true
.
static VALUE false_xor(VALUE obj, VALUE obj2) { return RTEST(obj2)?Qtrue:Qfalse; }
Always returns the string “nil”.
static VALUE nil_inspect(VALUE obj) { return rb_usascii_str_new2("nil"); }
Only the object nil responds true
to nil?
.
static VALUE rb_true(VALUE obj) { return Qtrue; }
Returns zero as a rational. The optional argument eps
is always ignored.
static VALUE nilclass_rationalize(int argc, VALUE *argv, VALUE self) { rb_check_arity(argc, 0, 1); return nilclass_to_r(self); }
Always returns an empty array.
nil.to_a #=> []
static VALUE nil_to_a(VALUE obj) { return rb_ary_new2(0); }
Returns zero as a complex.
static VALUE nilclass_to_c(VALUE self) { return rb_complex_new1(INT2FIX(0)); }
Always returns zero.
nil.to_f #=> 0.0
static VALUE nil_to_f(VALUE obj) { return DBL2NUM(0.0); }
Always returns an empty hash.
nil.to_h #=> {}
static VALUE nil_to_h(VALUE obj) { return rb_hash_new(); }
Always returns zero.
nil.to_i #=> 0
static VALUE nil_to_i(VALUE obj) { return INT2FIX(0); }
Returns zero as a rational.
static VALUE nilclass_to_r(VALUE self) { return rb_rational_new1(INT2FIX(0)); }
Always returns the empty string.
static VALUE nil_to_s(VALUE obj) { return rb_cNilClass_to_s; }
Or—Returns false
if obj is nil
or false
; true
otherwise.
static VALUE false_or(VALUE obj, VALUE obj2) { return RTEST(obj2)?Qtrue:Qfalse; }