Pie language

This is my implementation of the Pie language, as described (mostly) in The Little Typer by Daniel P. Friedman and David Tharne Christiansen. With additional goal of learning Rust.

Building

Projects follows standard Rust conventions and is buildable via cargo. However parser is utilizing tree sitter and grammar definition for the Pie language is kept in the tree-sitter-pie directory. One can regenerate grammar generated source by running tree-sitter generate in the grammar directory. Those artifacts are kept under version control, so it’s not necessary to generate them if no changes to language grammar definition are made.

pie executable

pie is your typical compiler executable. Point it to your source file and it will try to normalise expressions within.

repl executable

Besides standard compiler, project provides read, evaluate, print loop kind of program for easier experimentation with the language.

library

Executables are just thin programs that make use of the library modules, found in the lib/ directory.

Nix shell

Project contains nix flake, for reproducible building and providing development shell, with all the necessary dependencies. It’s not required to use it, but I think it makes life a lot easier. One can enter development shell by running:

nix develop

In the project root directory. There is additional shell, tailored to the development of language grammar. One can enter it by executing:

nix develop tree-sitter

direnv config

In order to enter shell automatically one can leverage direnv. There is simple .envrc file in the project root directory. Additionally grammar definition directory tree-sitter-pie/ has it’s own direnv config so it will switch to the grammar development shell automatically. One has to manually opt in into automatic shell selection by running direnv allow in the desired directory.

cache

Project uses free cachix cache for nix artifacts (development shell included). See the details here, but it should be as easy as running:

cachix use famisoft