anchor.diff:    # Construct a Unix-style search path consisting of each `subDir"
     # directory of the given list of packages.  For example,
     # `makeSearchPath "bin" ["x" "y" "z"]' returns "x/bin:y/bin:z/bin".
  -  makeSearchPath = subDir: packages: 
  +  makeSearchPath = subDir: packages:
       concatStringsSep ":" (map (path: path + "/" + subDir) packages);
   
   
  
positive.code:       else
          s;
  
          
    # Return true iff string v1 denotes a version older than v2.
    versionOlder = v1: v2: builtins.compareVersions v2 v1 == 1;
  
  
  }
  
negative.code:   # Map a function over a list and concatenate the resulting strings.
    concatMapStrings = f: list: concatStrings (map f list);
    concatImapStrings = f: list: concatStrings (lib.imap f list);
  
  
    # Place an element between each element of a list, e.g.,
    # `intersperse "," ["a" "b" "c"]' returns ["a" "," "b" "," "c"].
  