you're going to love dis

I always used to wonder how python is interpreted and how does it exactly work under the hood during my journey of learning Python. As Python is an interpreted language, I was wondered how this the interpretation works under the hood.

The best practice is to reverse engineer the problem to its component parts. This is going to take it to the byte level.

The dis module supports the analysis of CPython bytecode by disassembling it, with the help of dis you can see what byte level operations are being done by your code.

Enough details, let’s see it in action. I made a foo.py file with a very trivial function for showcasing.

import dis
def run(x: int) -> int:
    return x + 1

if __name__ == "__main__":
    dis.dis(run)

>> python foo.py
 4   0 LOAD_FAST                0 (x)
     2 LOAD_CONST               1 (1)
     4 BINARY_ADD
     6 RETURN_VALUE

LOAD_FAST: is used for local variables, accessing the value in an array by index
LOAD_CONST: instruction is used to load a constant onto the stack
BINARY_ADD : is used to add the two values
RETURN_VALUE : is used to return this value from the function