Crafting Interpreters

Work in progress!

• typechecking instead of runtime casting

• make operators built in functions

• implement mixfix parsing (see above)

• Unit tests for unit testable stuff

• Check std::shared_ptr usage

• Two level language: https://dl.acm.org/doi/10.5555/130665, https://arxiv.org/pdf/cs/9810010.pdf
• Compile with LLVM
• STM

I personally don't like code generation, as it's pretty hard to debug, and involves mushing together strings in an extremely error-prone way. Since there aren't that many classes involved (yet! still to be seen if this holds up), I just typed them out manually.

Since expressions are represented by std::shared_ptrs, it's pretty easy to "pattern match" by "std::dynamic_pointer_cast"-ing in a cascade of ifs. Another possibility would have been to use std::variant and std::visit.

The book completely glosses over testing, which (in my opinion) is not a great thing, testing interpreters/compilers is far from trivial. I use approval tests for parsing.

• https://flow.org/en/docs/lang/