Question about "puts" "Kernel.puts" "Kernel::puts"

wikii

where are the differences bewteen puts , Kernel.puts ,Kernel::puts?

wikii

Thank you.
regard.

tt_su

Nothing - just one of Ruby's multiple ways of doing things.
All Kernel methods are available available in the global scope - that is - they are available everywhere.

puts == Kernel.puts == Kernel::puts

To be more specific, All objects inherit Kernel - because all objects inherit Object.

` Object.ancestors

=> [Object, Kernel]`

The . vs :: is just a syntax difference that has no affect on the behaviour.

In practise people use . for method calls, and :: for constants.

MyModule::MyClass.mymethod
MyModule::MyClass::MyConstant

Dan Rathbun

Functionally, there is no difference.

BUT.. technically, Kernel::puts(), is a COPY of the instance edition of puts() that got mixed into Object, and will get inherited by ALL other classes and modules.

The Ruby Core Team wrote the Kernel module as both a Mixin and a Library module. They used the module_function() method, so that all the library instance methods (that get mixin in using include,) had module method copies made. These copies can only be called by qualifying them with the Kernel module name.

[ruby:1c8jtequ]Kernel.module_eval "class<<self; method(:puts).inspect; end;"
>> #<Method: Class(Kernel)#puts>
Kernel.module_eval "method(:puts).inspect;" %(#000000)[>> #<Method: Kernel.puts>]