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AdvancedTutorials/12_Decorators.py

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+# Decorators allow you to make simple modifications to callable objects like functions, methods, or classes. We shall deal with functions for this tutorial. The syntax
+
+# @decorator
+# def functions(arg):
+#     return "value"
+
+# #Is equivalent to:
+# def function(arg):
+#     return "value"
+# function = decorator(function) # this passes the function to the decorator, and reassigns it to the functions
+
+# function(5)
+
+
+def repeater(old_function):
+    def new_function(*args, **kwds): # See learnpython.org/en/Multiple%20Function%20Arguments for how *args and **kwds works
+        old_function(*args, **kwds) # we run the old function
+        old_function(*args, **kwds) # we do it twice
+    return new_function # we have to return the new_function, or it wouldn't reassign it to the value
+
+@repeater
+def multiply(num1, num2):
+    print(num1 * num2)
+
+multiply(2, 3)
+
+
+
+
+def multiply(multiplier):
+    def multiply_generator(old_function):
+        def new_function(*args, **kwds):
+            return multiplier * old_function(*args, **kwds)
+        return new_function
+    return multiply_generator # it returns the new generator
+
+# Usage
+@multiply(3) # multiply is not a generator, but multiply(3) is
+def return_num(num):
+    return num
+
+# Now return_num is decorated and reassigned into itself
+return_num(5) # should return 15