members/lib.nix

   1 { lib }:
   2 let
   3   chrs = lib.listToAttrs (lib.imap (i: v: { name = v; value = i + 96; }) lib.lowerChars);
   4   ord = c: builtins.getAttr c chrs;
   5 in
   6 {
   7   # Make a unique UID from a 4-char identifier
   8   mkUid = id:
   9     let
  10       chars = lib.stringToCharacters (builtins.substring 0 4 id);
  11       n = builtins.map (c: lib.mod (ord c) 10) chars;
  12       s = builtins.concatStringsSep "" (builtins.map (i: builtins.toString i) n);
  13     in
  14       assert builtins.stringLength id >= 4;
  15       assert builtins.length chars == 4;
  16       1000 + lib.toInt s;
  17 }