to-edn/to-edn.nix

{ lib }:

with lib;
let
  isSymbol = str: isNull (match "^'.+" str);
  stripQuote = head (match "^'(.+)");
  parseStr = str: if (isSymbol str) then (stripQuote str) else ''"${str}"'';

  join-str = concatStringsSep " ";
  toEDN = ds:
    if isString ds then
      parseStr ds
    else
      (if isInt ds then
        ds
      else
        (if isList ds then
          "[ ${join-str (map toEDN ds)} ]"
        else
          (if isAttrs ds then
            "{ ${join-str (mapAttrs (k: v: ":${k} ${toEDN v}") ds)} }"
          else
            throw "unsupported type: ${builtins.typeOf ds}: ${ds}")));

in { ds }: toEDN ds