anchor.diff:          set packpath-=~/.vim/after
           set packpath+=${packDir packages}
           set packpath+=~/.vim/after
  +
  +        filetype indent plugin on | syn on
         '');
   
     in writeText "vimrc" ''
  -  " minimal setup, generated by NIX
  +  " configuration generated by NIX
     set nocompatible
   
     ${vamImpl}
     ${pathogenImpl}
     ${plugImpl}
     ${nativeImpl}
  -
  -  filetype indent plugin on | syn on
   
     ${customRC}
     '';
  
positive.code: 
        in assert builtins.hasAttr "vim-addon-manager" knownPlugins;
        ''
          let g:nix_plugin_locations = {}
          ${lib.concatMapStrings (plugin: ''
            let g:nix_plugin_locations['${plugin.pname}'] = "${plugin.rtp}"
  
negative.code:       ''
          let &rtp.=(empty(&rtp)?"":',')."${vimPlugins.pathogen.rtp}"
          execute pathogen#infect('${pluginsEnv}/{}')
  
          filetype indent plugin on | syn on
        '');
  
        /* vim-plug is an extremely popular vim plugin manager.
  