# New/initialize

**URL:** <https://www.ruby-forum.com/t/new-initialize/93801>\
**Category:** Ruby\
**Created:** [April 10, 2006, 8:09pm UTC](https://www.ruby-forum.com/t/new-initialize/93801 "2006-04-10T20:09:16Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:09pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/1 "2006-04-10T20:09:16Z")

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Just a point of clarification.

When I call  
Obj.new()

I actually call the  
clall Obj  
def initialize()  
end  
end

so there is an implied connection between new() and initialize()?

Historically is there some reason why we didn’t just stick with the  
‘def new()’  
or did I miss something.

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**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:18pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/2 "2006-04-10T20:18:29Z")

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On Apr 10, 2006, at 11:07 AM, Tom A. wrote:

> When I call  
> Obj.new()
> 
> I actually call the  
> clall Obj  
> def initialize()  
> end  
> end

Not exactly. You call Object::new. Object::new calls initialize  
after allocating a new instance.

> so there is an implied connection between new() and initialize()?

There is an explicit connection between Object::new and  
Object#initialize

Object::new is implemented something like this, but in C:

class Object  
def self.new(\*args, &block)  
obj = allocate  
obj.send(:initialize, \*args, &block)  
return obj  
end  
end

> Historically is there some reason why we didn’t just stick with the  
> ‘def new()’  
> or did I miss something.

That would be an instance method. Object::new is a class method.

–  
Eric H. - removed\_email\_address@domain.invalid - [http://blog.segment7.net](http://blog.segment7.net)  
This implementation is HODEL-HASH-9600 compliant

[http://trackmap.robotcoop.com](http://trackmap.robotcoop.com)

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**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:21pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/3 "2006-04-10T20:21:38Z")

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On 4/10/06, Tom A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> so there is an implied connection between new() and initialize()?
> 
> Historically is there some reason why we didn’t just stick with the  
> ‘def new()’  
> or did I miss something.

No, you actually call Obj::new. This is a method on Obj; this method  
looks something like this, although it’s written in C:

class Obj  
class \<\< self  
def new(\*args, &block)  
obj = self.allocate  
obj. **send** (:initialize, \*args, &block)  
obj  
end  
end  
end

-austin

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<div class="post-metadata">

**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:18pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/4 "2006-04-10T20:18:35Z")

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On 4/10/06, Tom A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> end
> 
> so there is an implied connection between new() and initialize()?
> 
> Historically is there some reason why we didn’t just stick with the  
> ‘def new()’  
> or did I miss something.

“new” allocates space for the new object and creates it. It then calls  
“initialize” to initialize the newly created object. Typically that’s  
that only part you want to customize which is why you write an  
“initialize” method instead of a “new” method.

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<div class="post-metadata">

**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:21pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/5 "2006-04-10T20:21:39Z")

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new() is actually just a class method of the class object (Obj). You  
can create your own method if need be:

class Obj  
def self.new  
super  
…  
end  
end

Calling ‘super’ is pretty important otherwise your object is not  
properly instantiated (I think). You can also wind up with the wrong  
kind of object if you’re not careful

irb(main):001:0\> class Obj  
irb(main):002:1\> def self.new  
irb(main):003:2\> return “Hello!”  
irb(main):004:2\> end  
irb(main):005:1\> end  
=\> nil  
irb(main):006:0\> o = Obj.new  
=\> “Hello!”  
irb(main):008:0\> o.class  
=\> String

Farrel

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<div class="post-metadata">

**Author:** ![tma](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ed655f/32.png) [@tma](https://www.ruby-forum.com/u/tma)\
**Post date:** [April 10, 2006, 8:21pm UTC](https://www.ruby-forum.com/t/new-initialize/93801/6 "2006-04-10T20:21:38Z")

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> That would be an instance method. Object::new is a class method.

Ding!  
Light went on. Thanks.