Why the `singleton` methods can't be defined on `Fixnum`,`Bignum`,`Float`,`Symbol` class objects, but ` FalseClass` and `TrueClass` can have?
ruby, ruby-2.0
Solution
As the Ruby Docs say:
There is effectively only one Fixnum object instance for any given integer value, so, for example, you cannot add a singleton method to a Fixnum.
The same is true for `Bignum`, `Float` and `Symbol`
Problem
Why the `singleton` methods can't be defined on `Fixnum`,`Bignum`,`Float`,`Symbol` class objects, but `FalseClass` and `TrueClass` can have? ``` C:\>ruby -v ruby 2.0.0p0 (2013-02-24) [i386-mingw32] C:\>irb --simple-prompt DL is deprecated, please use Fiddle 11111111111.class #=> Bignum class << 11111111111 ; end #TypeError: can't define singleton # from (irb):2 # from C:/Ruby200/bin/irb:12:in `<main>' 1111.class #=> Fixnum class << 1111 ; end #TypeError: can't define singleton # from (irb):4 # from C:/Ruby200/bin/irb:12:in `<main>' 11.11.class #=> Float class << 11.11 ; end #TypeError: can't define singleton # from (irb):6 # from C:/Ruby200/bin/irb:12:in `<main>' :name.class #=> Symbol class << :name ; end #TypeError: can't define singleton # from (irb):8 # from C:/Ruby200/bin/irb:12:in `<main>' ```