Lox in C++

An implementation of Crafting Interpreters's Lox in C++20.

// fibonacci.lox
fun fib(n) {
  if (n <= 1) return n;
  return fib(n - 2) + fib(n - 1);
}

print fib(7); // prints 13

Extensions:

• Properly nesting C-style /*...*/ block comments.
• Added support for the ternary operator and the comma operator.
• Implemented break statements inside loops.

Building and running

Prerequisites:

• cmake v3.25
• llvm v15 (for clangd and clang-format)
• ninja (optional)
• rlwrap (optional)

mkdir build
cd build

cmake -GNinja ..
ninja

This will produce two binaries in bin/ which you can run with

# Run interpreter
bin/lox
# Use rlwrap to scroll through history
rlwrap bin/lox

# Run tests (expects to be called from the build/ dir)
(cd bin && ./tests)

So far, I've been able to build and run on WSL and my M1 MacBook using clang 15.0.6.

Todos

• Write about the visitor pattern.
• Try using mpark/patterns and refactor code with variants.
• Try to merge literals and values (don't need both) - make everything a literal