SmartWrappers
A Python 3 library to manipulate objects with shared mutable wrappers.
Installing
Python 3.6.8 or higher is required
To install the library, you can just run the following command:
# Linux/macOS
python3 -m pip install -U smartwrappers
# Windows
py -3 -m pip install -U smartwrappersCases to use
# We cannot change immutable objects.
# Trying to change them we just create other objects.
def plus_five(x):
x += 5 # Creating another object here.
x = 1
plus_five(x)
print(x) # >>> 1
# Standard solution: rewrite our code in a way our function
# calculates a new value and then we just reassign it to variables
# whose values we need to change.
def get_plus_five(x):
return x + 5
x = 1
x = get_plus_five(x)
print(x) # >>> 6What if we have many objects of the same value and want them to have common state?
a = 1
b = a
c = b
# ...
a = get_plus_five(a)
# What about b, c and other links
# at different places of our project?Usage
We can use smart wrappers for that purpose:
from smartwrappers import wrap
a = wrap(1) # or explicitly a = SmartWrapper(1)
b = a
c = b
print(a()) # >>> 1
print(b()) # >>> 1
print(c()) # >>> 1
a(5)
print(a()) # >>> 5
print(b()) # >>> 5
print(c()) # >>> 5
def plus_five(x):
x(x() + 5)
plus_five(a)
print(a()) # >>> 10
print(b()) # >>> 10
print(c()) # >>> 10Matrices
We can use smart wrappers for wrapping lists:
from smartwrappers import wrap_list
a = wrap_list([1, 2, 3])
b = [a[0], a[1], a[2]]
print(a) # >>> [1, 2, 3]
print(b) # >>> [1, 2, 3]
a[1] = 'a'
print(a) # >>> [1, 'a', 3]
print(b) # >>> [1, 'a', 3] => wrappers behave like references to mutable content.We can wrap lists with any levels of dimensions:
a = wrap_list([[1, 2], [3, 4]], dimensions=2)
b = [[a[0][0], a[1][0]], [a[0][1], a[1][1]]] # Transposed matrix.
# a is:
# 1 2
# 3 4
# b is transposed matrix a:
# 1 3
# 2 4
a[0][1](0)
# a is:
# 1 0
# 3 4
# b keeps changes:
# 1 3
# 0 4If we don't want to put inside our wrapper values of different types we can use StrictSmartWrapper:
from smartwrappers import wrap_strictly
a = wrap_strictly('hello', str)
a('world') # OK.
a(5) # Error.
b = wrap_strictly('hello', int) # Error.
