pylox

Feature-complete Python interpreter for Bob Nystrom's Lox programming language. I made this as I read the first half of Crafting Interpreters, which I'd strongly recommend.

Overview

pylox is a tree-walk interpreter with a fairly simple structure. First, the scanner scans Lox source code and converts it into tokens. The parser takes these tokens and creates a syntax tree. Next, the resolver does a single pass over the syntax tree and handles getting scopes correct. Finally, using the information from the resolver and the syntax tree from the parser, the interpreter actually runs code.

Contents

The table lays out important directories/files and their purposes:

directory/file	description
lox/	Directory with actual Lox interpreter implementation
lox/environment.py	Holds a given scope's values for the interpreter
lox/error_handler.py	Logs and keeps track of errors
lox/interpreter.py	Executes statements
lox/lox_.py	Runs Lox code from a file or in a REPL on the command line
lox/parser_.py	Turns tokens from the scanner into a syntax tree
lox/resolver.py	Resolves variable scopes using the syntax tree from the parser
lox/scanner.py	Turns raw Lox source code into tokens
test/	Lox tests from the main Crafting Interpreters Repository
tool/	Garbage metaprogramming hacks (don't do this)
run_tests.py	Script to run tests

Further reading

Again, I'd strongly recommend Crafting Interpreters.

Lots of people have created their own Lox implementations. This list contains implementations in Python and many other languages.