TwoPy

A toy Python interpreter written in C++26.

Usage

• Ensure you have CMake 3.20+ and a C++26 supporting compiler.
• Enable helper.sh.
• Do ./helper.sh help for usage info. Use ./helper.sh build debug-build <your build tool> to create the binary.

Design

This is based off typical compiler stages:

• Lexer: Tokenizes Python source code.
• Parser: Builds an AST via recursive descent with Pratt's parsing
• Bytecode Compiler: Compiles the AST into bytecode with constant/name pooling, scope-aware variable access, and jump patching
• Stack-Based VM: Executes bytecode with a global/local variable env with its own stack and instruction pointer.

Supported Python Features (around 3.8 - 3.9)

• Basic variable store/load, comparisons, arithmetic.
• print??

Contributors

Special thanks to DrkWithT for helping refactor the match and consume functions in the Parser namespace to use metaprogramming, eliminating verbose consume(T) || consume(T) chains for larger conditionals.

TODO

• VM Refactor 1
  • New stack representation supporting arbitrary peeking (presized vector with SP, BP)
  • Stack of call frames for recursion support
• Get Fibonacci working as microbenchmark 1
• Support nested functions
• For loops
• Ternary expressions?
• Support lists
• Support dictionaries