Python++

A robust Java-style OOP system for Python, with support for statics, encapsulation, and inheritance.

View on PyPI / Built by Kento Nishi and Ronak Badhe

Python++ allows Python programmers to use object oriented programming principles in Python.

Installation

The package is available on PyPI. You can install the package with the following command:

pip install pythonpp

Usage

Importing the Library

You can import Python++ with the following:

from pythonpp import *

Class Declaration

Declare Python++ classes with the @PythonPP decorator.

@PythonPP
class MyClass:
    pass # class code here

Namespace and Scopes

Declare variables and methods for Python++ classes within namespace.

@PythonPP
class MyClass:
    def namespace(public, private):
        pass # methods and variables here

Code within namespace has access to the following scopes:

Static Initializers

Declare static initializers for Python++ classes using the @staticinit decorator. Static initializers do not have access to instance variables and methods. Static initializers cannot have input parameters.

@PythonPP
class MyClass:
    def namespace(public, private):
        @staticinit
        def StaticInit():
            public.static.publicStaticVar = "Static variable (public)"
            private.static.privateStaticVar = "Static variable (private)"

Alternatively, static variables can be declared in the bare namespace if the variable assignments are constant. Using bare static variable declarations are not recommended.

Constructors

Constructors can be declared using the @constructor decorator. Constructors can have input parameters.

@PythonPP
class MyClass:
    def namespace(public, private):
        @constructor
        def Constructor(someValue):
            public.publicInstanceVar = "Instance variable (public)"
            public.userDefinedValue = someValue

Method Declarations

Methods are declared using the @method(scope) decorator with the public and private scopes in namespace.

@PythonPP
class MyClass:
    def namespace(public, private):
        @method(public)
        def publicMethod():
            pass # public instance method here

        @method(private)
        def privateMethod():
            pass # private instance method here

        @method(public.static)
        def publicStaticMethod():
            pass # public static method here

        @method(private.static)
        def privateStaticMethod():
            pass # private static method here

Special Methods

Declare special built-in methods using the @special decorator.

@PythonPP
class MyClass:
    def namespace(public, private):
        @special
        def __str__():
            return "Some string value"

Inheritance

Classes can extend other classes using standard Python class inheritance.

@PythonPP
class ParentClass:
    def namespace(public, private):
        @staticinit
        def StaticInit():
            public.static.staticVar = "Static variable"

        @constructor
        def Constructor(param):
            print("Parent constructor")
            public.param = param

@PythonPP
class ChildClass(ParentClass): # ChildClass extends ParentClass
    def namespace(public, private):
        @staticinit
        def StaticInit():
            ParentClass.staticinit() # Call parent static initializer
            public.static.staticVar2 = "Static variable 2"

        @constructor
        def Constructor(param):
            # Call parent constructor
            ParentClass.constructor(param)

Quickstart Example

from pythonpp import *

@PythonPP
class ParentClass:
    def namespace(public, private):
        @staticinit
        def StaticInit():
            public.static.publicStaticVar = "Public static variable"
            private.static.privateStaticVar = "Private static variable"

        @constructor
        def Constructor(parameter):
            private.privateVariable = parameter

@PythonPP
class ChildClass(ParentClass):
    def namespace(public, private):
        @staticinit
        def StaticInit():
            ParentClass.staticinit()

        @constructor
        def Constructor(parameter):
            ParentClass.constructor(parameter)
            public.publicVariable = "Public variable"
            private.privateVariable = "Private variable"

        @method(public)
        def getPrivateVariable():
            return private.privateVariable

        @method(public.static)
        def getPrivateStaticVar():
            return private.static.privateStaticVar

        @special
        def __str__():
            return "ChildClass object"

print(ChildClass.publicStaticVar)
# > Private static variable
print(ChildClass.getPrivateStaticVar())
# > Private static variable

obj = ChildClass("Parameter value")
print(obj)
# > ChildClass object
print(obj.publicVariable)
# > Public variable
print(obj.getPrivateVariable())
# > Parameter value
try:
    obj.privateVariable # results in an error
except Exception as e:
    print(e)
# > 'ChildClass' object has no attribute 'privateVariable'

Full Example

You can view the full example Jupyter notebook here.