anchor.diff:  {
     # general
     lib
  -, callPackage
  -, runCommand
   , resholvePackage
   , bash
   , shellcheck
  
positive.code: 
    # check based on https://github.com/bashup/events/blob/master/.dkrc
    checkPhase = ''
      SHELLCHECK_OPTS='-e SC2016,SC2145' ${shellcheck}/bin/shellcheck ./bashup.events
      ${bash}/bin/bash -n ./bashup.events
      ${bash}/bin/bash ./bashup.events
    '';
  
    solutions = {
  
negative.code:   inherit src;
  
    installPhase = ''
      runHook preInstall
      install -Dt $out/bin bashup.events
      runHook postInstall
    '';
  
    inherit doCheck;
  