Decorators as higher-order functions

The core idea of a decorator is to transform some original function into another form. A decorator creates a kind of composite function based on the decorator and the original function being decorated.

A decorator function can be used in one of the two following ways:

• As a prefix that creates a new function with the same name as the base function as follows:

  @decorator
  def original_function():
      pass
  

• As an explicit operation that returns a new function, possibly with a new name:

  def original_function():
      pass
  original_function= decorator(original_function)
  

These are two different syntaxes for the same operation. The prefix notation has the advantages of being tidy and succinct. The prefix location is more visible to some readers. The suffix notation is explicit and slightly more flexible. While the prefix notation is common, there is one reason for using the suffix notation: we might not want the resulting function to replace the original function...