Parser combinators in Nix. Nix isn't meant to be a general purpose programming language, so using parser combinators like this should really be avoided, unless:

• Nix's built-in regex tools won't work for your use case
  • You usually don't need to parse things in Nix, and when you do, you usually don't need anything more powerful than regex
• Parsing performance will not be a bottleneck for the build
  • If it is, consider implementing your parser in your language of choice and using nix to invoke it
• It's difficult to pass results of parsing in another language back to Nix

Don't ask what I actually needed this for.

Include by fetching via usual means (fetchTarball, fetchFromGitHub, etc.):

let
  version = "v0.1.0";
  sha256 = "...";

  nix-parsec = import (builtins.fetchTarball {
    url = "https://github.com/nprindle/nix-parsec/archive/${version}.tar.gz";
    inherit sha256;
  });

  inherit (nix-parsec) parsec lexer;
in ...

At the top level, two attribute sets are exported:

• parsec: Parser combinators and functions to run parsers
• lexer: Combinators for parsing token-related things

The parsing/lexing APIs roughly corresponds to those of Haskell's megaparsec library. See examples/ for some example parsers.