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https://github.com/petercamilleri/full_clone

A recursive, deep copy version of clone with exclusion control and tolerance of non-clonable values.
https://github.com/petercamilleri/full_clone

deep gem ruby ruby-gem safe utility

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A recursive, deep copy version of clone with exclusion control and tolerance of non-clonable values.

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README 

        
# FullClone



The standard clone method creates a fresh instance of most (non-scalar) objects

but does not clone internal state. This internal state remains aliased in the

cloned copy. The full_clone method digs deep and makes copies of these internal

variables, not just arrays and hashes. It also allows classes to specify an

exclusion list of variables that are not to be processed.



New for version 0.0.10, now 84% faster (at least full_dup was in my tests).



This comprehensive approach creates another issue to be resolved. In Ruby, if an

attempt is made to clone an immutable data item like a number, an error occurs.

The justification for this uncharacteristic strictness is not at all clear, but

it does mean that the clone operation must be applied with great care.



Unlike the standard clone method, the full\_clone method does not throw an

exception when it sees un-clonable value objects like 42 or true. These values

simply return themselves. This is deemed correct because those types of objects

are immutable and do not need to be duped. Instead of raising an exception, the

code returns the immutable object instead.



Another issue that this gem deals with is that of data with looping reference

chains. To handle this, the code tracks object ID values and does not re-clone

data that has already been cloned. Thus even nasty edge cases are handled

without any special effort on the part of the application programmer.



## Family Overview



This gem is a member of a family of four gems that all provide data copying

services in a safe, easy to use format. The following outlines the available

gems and how to chose from among them.



Depth / Action | Need to copy all. | Need to copy data only.

---------------|------------------------------|------------

Need a shallow copy | require 'safe\_clone' | require 'safe\_dup'

Need a full copy    | require 'full\_clone' | require 'full\_dup'




**Notes**

* Since none of these gems override the default clone and dup

methods, the default behaviors remain available. Further, if multiple,

differing requirements exists, more than one family member gem may be

employed in the same project without fear of conflict.

* If multiple family gems are employed, they will each need to be installed and

required into the application. See below for details.

* Meta-data attributes include the frozen status and singleton methods. However

the tainted status is always copied.



## Installation



Add this line to your application's Gemfile:



    gem 'full_clone'



And then execute:



    $ bundle



Or install it yourself as:



    $ gem install full_clone



The safe_dup gem is at: ( https://rubygems.org/gems/safe_dup )


The safe_clone gem is at: ( https://rubygems.org/gems/safe_clone )


The full_dup gem is at: ( https://rubygems.org/gems/full_dup )


The full_clone gem is at: ( https://rubygems.org/gems/full_clone )



## Usage



    require 'full_clone'



then, in those places where regular clone was problematic, use:



    foo = my_object.full_clone



instead of



    foo = my_object.clone



To exclude some instance variables from the deep cloning process, define a

full_clone_exclude method in the required class:



```ruby

def full_clone_exclude

  [:@bad_var1, :@bad_var2, :@bad_var_etc]

end

```

This also can be applied to arrays and hashes. In this case, it is possible to

define a singleton method on the cloned data. Then the exclude method would

return an array of array indexes or hash keys to be omitted from the full clone

recursion. Here is an example that never clones the first two elements of the

array:



```ruby

my_array.define_singleton_method(:full_clone_exclude) { [0, 1] }

```



## Notes



The full_clone gem tracks its progress and handles data objects that

contain loops, cycles, and other forms of recursion. In order to do this,

it relies heavily on the object_id property of the data being copied.

If object_id is broken, then full_clone and hashes and ... will also be

broken!



## Contributing



#### Plan A



1. Fork it ( https://github.com/PeterCamilleri/full_clone/fork )

2. Create your feature branch (`git checkout -b my-new-feature`)

3. Commit your changes (`git commit -am 'Add some feature'`)

4. Push to the branch (`git push origin my-new-feature`)

5. Create new Pull Request



#### Plan B



Go to the GitHub repository and raise an issue calling attention to some

aspect that could use some TLC or a suggestion or an idea.



## License



The gem is available as open source under the terms of the

[MIT License](./LICENSE.txt).



## Code of Conduct



Everyone interacting in the fully_freeze project’s codebases, issue trackers,

chat rooms and mailing lists is expected to follow the

[code of conduct](./CODE_OF_CONDUCT.md).