Documentation
https://github.com/python/cpython
cPython is the standard implementation of the Python programming language. It is written in C and provides a way to run Python code on a computer. It is open source, which means that developers can view and modify the code to suit their needs.
cPython reads and interprets Python code in several steps. First, it reads the code and converts it into bytecode, which is a low-level representation of the code that can be executed by the Python virtual machine. The virtual machine reads the bytecode and executes it, producing the output of the program.
One of the key features of cPython is its ability to dynamically interpret Python code. This means that code can be executed on-the-fly, without the need for compilation. This makes it a popular choice for scripting and rapid prototyping.
To illustrate how C interprets Python code, consider the following code snippet:
def add_numbers(x, y):
return x + y
result = add_numbers(3, 5)
print(result)
When this code is executed by cPython, it is first compiled into bytecode. The bytecode for this code might look something like this:
1 0 LOAD_CONST 0 (<code object add_numbers at 0x7f5b0f5d69c0, file "<stdin>", line 1>)
2 LOAD_CONST 1 ('add_numbers')
4 MAKE_FUNCTION 0
6 STORE_NAME 0 (add_numbers)
3 8 LOAD_NAME 0 (add_numbers)
10 LOAD_CONST 2 (3)
12 LOAD_CONST 3 (5)
14 CALL_FUNCTION 2
16 STORE_NAME 1 (result)
4 18 LOAD_NAME 2 (print)
20 LOAD_NAME 1 (result)
22 CALL_FUNCTION 1
24 POP_TOP
26 LOAD_CONST 4 (None)
28 RETURN_VALUE
This bytecode is then executed by the Python virtual machine, producing the output 8.
To understand how C interprets this code, we would need to examine the C code that implements the Python virtual machine. This code is complex and beyond the scope of this guide, but it is worth noting that the virtual machine is essentially a large switch statement that reads and executes bytecode instructions.
In summary, cPython is the standard implementation of the Python programming language. It reads and interprets Python code by converting it into bytecode and executing it using the Python virtual machine. While the details of how C interprets Python code are complex, understanding the basics of how bytecode is executed can help developers write more efficient and effective Python code.