pylox

Pylox is a Lox interpreter, implemented in Python, based on the book Crafting Interpreters by Bob Nystrom.

I am currently working through Chapter 9.

Also, I have implemented some of the chapter challenges so far, but not all. Eventually I want to 100% the Tree-Walk Interpreter section

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Table of Contents

• pylox
  • Demo
    • REPL
    • Verbose REPL
    • Source files
  • Installation
  • Challenges
  • Architecture of pylox
  • License

Demo

REPL

Verbose REPL

Useful for debugging

Source files

Installation

Pull from Github

Requires Python 3.10 or later

I use Hatch to manage the Python environment

Challenges

Ch 4. Scanning

• Support for C-style block comments (NOT nestable)

Ch 5. Representing Code

• AST print Reverse Polish Notation

Ch 6. Parsing Expressions

• Comma Operator
• Ternary Operator
• Error productions for binary operators without left-hand side expression

Ch 7. Evaluating Expressions

• [] define "+" so that if one operand is string, it coerces other operand to string I don't really like this behaviour with strings. Between floats and ints this is okay, but Lox anyways only has float type
• handle zero division error

Ch 8. Statements and State

• Evaulate expressions in REPL
• Runtime error when accessing uninitialized variables

Ch 9. Control Flow

Architecture of pylox

cli: handles command line interface (cli) options, cli formatting, stdin/stdout.

utils: helper utilities; not particularly significant to the function of the app, but convenient.

engine: the core of the pylox interpreter

License

pylox is distributed under the terms of the MIT license.