anchor.diff:          text = ''
             var fs = require('fs');
             var url = require('url');
  -          
  +
             /*
              * Replaces an impure version specification by *
              */
             function replaceImpureVersionSpec(versionSpec) {
                 var parsedUrl = url.parse(versionSpec);
  -              
  +
                 if(versionSpec == "latest" || versionSpec == "unstable" ||
                     versionSpec.substr(0, 2) == ".." || dependency.substr(0, 2) == "./" || dependency.substr(0, 2) == "~/" || dependency.substr(0, 1) == '/')
                     return '*';
  
positive.code:     in
      stdenv.lib.makeOverridable stdenv.mkDerivation {
        name = "node-shell-${name}-${version}";
        
        buildInputs = [ python nodejs ] ++ stdenv.lib.optional (stdenv.isLinux) utillinux ++ args.buildInputs or [];
        buildCommand = ''
          mkdir -p $out/bin
  
negative.code:       then
            # Figure out what directory has been unpacked
            packageDir="$(find . -maxdepth 1 -type d | tail -1)"
  
            # Restore write permissions to make building work
            find "$packageDir" -type d -print0 | xargs -0 chmod u+x
            chmod -R u+w "$packageDir"
  
            # Move the extracted tarball into the output folder
            mv "$packageDir" "$DIR/${packageName}"
        elif [ -d "${src}" ]
  