functional_programming

Functional Programming

A prototype for a meta-tool for Functional Programming in Python.

Content

The only real content of this project is make_functional() in utils/functional_tools.py.

The rest of the files are only to demonstrate how to use make_functional().

Motivation

Some backstory into what I used to do.

• I used to subclass some Python object type, like list for example.
• I subclass these object classes to override some methods I wanted to use, and make them return self.
  • To make them functional methods, and allow method chaining.

What is does

Which brings us to this prototype project.

• With this new make_functional() prototype,
  • I don't have to manually subclass each object individually.
  • Nor do I have to manually override each single method individually.
  • Instead, I can throw any object into it, and it'll override all methods and make them functional automatically.
  • I can also add normal functions to additional_methods that'll be callable as class methods for the new object.

How it does so

• This prototype is different from subclassing.
  • Instead, it creates a new wrapper class that sets the input (original) object as its _content attribute.
  • And for most methods of the original object, this wrapper class will 'inherit' them,
    • and apply them to _content, the stored original object.
    • and also return self each time it does so, allowing for methods to be chained.
      • But it can also be the case the original method originally returns something,
        • in which case it creates a new wrapper class with the return value as _content
          • The return value could be of the same object type or a different class entirely.
    • Exceptions that will not be inherited are the private methods (those starting with __).

Even more

• return_content() method is also created to return the current _content,
  • returning to the original class (or a different class if the object has been transformed)
• freeze() and restore() are also added to 'freeze' a state of _content
  • Allowing method chaining to transform it,
    • and then to return to the frozen content later within the same method chain.

Some notes on origin of this project

• This project was originally written as part of an employment test.
• I'll be writing new contents to demonstrate the use of make_functional() later when I have time.