Lox++

Interpreter for the Lox language implemented in C++, with additional features.

Features

Implements vanilla Lox according to Chapters 4-13 of Crafting Interpreters by Bob Nystrom, as well as the following extra challenges:

• Chapter 4 (Scanning):
  • C-style block comments
• Chapter 6 (Parsing):
  • Comma operator
  • Ternary operator
  • Error productions for binary operators
• Chapter 7 (Evaluating Expressions)
  • Type coercion for string concatenation
  • Divison by 0 error
  • Modulo operator
• Chapter 8 (Statements and State)
  • REPL support for both expressions and statements
  • Runtime error for unassigned variables
• Chapter 9 (Control Flow)
  • Break and continue statements
• Chapter 10 (Functions)
  • Anonymous functions
• Chapter 11 (Resolving and Binding)
  • Resolver error for unused local variables
  • More efficient environment representation via resolver indexing and vectors
• Chapter 12 (Classes)
  • Static methods and fields via metaclasses
  • Getter members
• Chapter 13 (Inheritance)
  • super keyword allows access to superclass fields in addition to methods

Usage

Build the interpreter:

make lox

• Interpreter: ./lox [path to program file]
• REPL: ./lox

Testing

Run the tests:

make test

Add new tests to the tests/ directory as follows:

• [test_name].lox contains the Lox program
• [test_name].expected contains the expected program output