Why Doesn\'t Python Throw an Error When Function or Method Calls Lack Parentheses?

Function and Method Call Omission

When encountering the absence of parentheses in a function or method call, it may seem questionable why an error does not occur. After all, methods are typically invoked with parentheses.

The reason for this is that functions and methods in Python are considered first-class objects, meaning they behave similarly to other objects like integers or strings. As such, they can be manipulated and stored like other variables.

In the given code example:

a = objectTest(1)
b = objectTest(1)

print(a.get_value == b.get_value)

The expression a.get_value retrieves the get_value method attached to object a as a reference without invoking it. Comparing this reference with b.get_value checks if they are the same method (same memory location). Hence, it evaluates to True.

This mechanism is particularly useful in certain scenarios:

• Passing References: Functions can be passed as arguments to other functions, without being called. This is used in multiprocessing, where a process can be assigned a callable to execute.
• Dynamic Call Specification: Functions can be specified without being called directly, such as in map() or filter(), allowing for dynamic function execution.
• Dynamic Lookup: Collections of functions can be created and searched based on string keys, like in the example with string operators.

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