{ depot, pkgs, lib, ... }:

let
  netencode = {
    rust = depot.nix.writers.rustSimpleLib
      {
        name = "arglib-netencode";
        dependencies = [
          depot.users.Profpatsch.execline.exec-helpers
          depot.users.Profpatsch.netencode.netencode-rs
        ];
      } ''
      extern crate netencode;
      extern crate exec_helpers;

      use netencode::{T};
      use std::os::unix::ffi::OsStrExt;

      pub fn arglib_netencode(prog_name: &str, env: Option<&std::ffi::OsStr>) -> T {
          let env = match env {
              None => std::ffi::OsStr::from_bytes("ARGLIB_NETENCODE".as_bytes()),
              Some(a) => a
          };
          let t = match std::env::var_os(env) {
              None => exec_helpers::die_user_error(prog_name, format!("could not read args, envvar {} not set", env.to_string_lossy())),
              // TODO: good error handling for the different parser errors
              Some(soup) => match netencode::parse::t_t(soup.as_bytes()) {
                  Ok((remainder, t)) => match remainder.is_empty() {
                      true => t,
                      false => exec_helpers::die_environment_problem(prog_name, format!("arglib: there was some unparsed bytes remaining: {:?}", remainder))
                  },
                  Err(err) => exec_helpers::die_environment_problem(prog_name, format!("arglib parsing error: {:?}", err))
              }
          };
          std::env::remove_var(env);
          t
      }
    '';
  };

in
depot.nix.readTree.drvTargets netencode