kalpitborkar / Python-Interpreter

A Python Interpreter written purely in Python

Byterun

A compact Python Interpreter written in Python.

What is Byterun?

• Byterun is a compact Python interpreter - a software that emulates a physical computer.
• Byterun is a Python interpreter written in Python.
• The Python interpreter is a virtual machine, in particular a stack machine - it manipulates several stacks to perform its operations.

The purpose of this project is to learn and practice concepts related to:

• Working and structure of Python interpreter CPython
• Stack machine
• Python OOP

Byterun structure

There are four kinds of objects in Byterun:

1. VirtualMachine class:

• The VirtualMachine class manages the highest level structure.
• Manages the call stack of frames and contains a mapping of instructions to operations.
• VirtualMachine stores the call stack, the exception state, and return values while they're being passed between frames.

2. Frame class:

• Every Frame instance has one code object.
• Manages:
  • The local, global, and builtin namespaces.
  • A reference to the previous frame.
  • A data stack.
  • A block stack.
  • The last instruction executed.

3. Function class:

• Creates a new frame in the interpreter everytime a function is called.
• Controls the creation of new Frame objects.

4. Block class:

• A Block just wraps the three attributes of blocks - type, handler and stack_height
• A Block is used for flow control, specifically exception handling and looping.

Call stack architecture

License

Distributed under the MIT License. See LICENSE.md for more information.

References

• CPython - ceval.c
• https://www.aosabook.org/en/500L/a-python-interpreter-written-in-python.html