Difference between include and require for modules?

ruby-talk
1

What I understand from require statement is that the argument to it is a
file, where as include requires module/class name.

But once I do a require for a specific ruby file which has various modules
and classes, doesn't these classes/modules get included automatically?
infact they do get automatically as I have tried doing so.

But in various files of ruby library I found that people use include
"modulename" after a require statement for the file which contains that
module.

Any reasons?

Thanks,
Jatinder

2

Jatinder Singh wrote:

What I understand from require statement is that the argument to it is a
file, where as include requires module/class name.

But once I do a require for a specific ruby file which has various modules
and classes, doesn't these classes/modules get included automatically?
infact they do get automatically as I have tried doing so.

But in various files of ruby library I found that people use include
"modulename" after a require statement for the file which contains that
module.

Any reasons?

Thanks,
Jatinder

Require is purely used to 'embed' files in other files.

Include is used on modules, and adds so-called "MixIn"-functionality.
It means you "import" the methods of the given Module into the current class (or Module?).

So, basically, you have a Module that provides some semi-generic functionality, then you have a class that wants to take advantage of this functionality.

Example:

module A
   def b
     "bar"
   end
end

class B
   include A
end

foo = B.new
foo.b
=> "bar"

I hope this helps!

Ps. this explanation might be horrible, and it might be wrong; I'm not a "professional" rubyist. :wink:

···

--
Kindest regards / Med vennlig hilsen,
  Jørgen P. Tjernø
  <jorgen@devsoft.no>