anchor.diff:    inherit src;
   
     installPhase = ''
  +    runHook preInstall
       install -Dt $out/bin bashup.events
  +    runHook postInstall
     '';
   
     inherit doCheck;
  
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 doInstallCheck;
    installCheckInputs = [ bash ];
    installCheckPhase = ''
      runHook preInstallCheck
      ${installCheck "${bash}/bin/bash"}
      runHook postInstallCheck
    '';
  
    meta = with lib; {
      inherit branch;
  