Add toDhall to lib

flake.nix

@@ -101,6 +101,29 @@
                   }) erisInfo);
             in assert length caps == 1; head caps;
 
+          generators = prev.generators // rec {
+            toDhall = x:
+              with builtins;
+              let concatItems = final.strings.concatStringsSep ", ";
+              in if isAttrs x then
+                "{ ${
+                  concatItems (prev.attrsets.mapAttrsToList
+                    (key: value: "${key} = ${toDhall value}") x)
+                } }"
+              else if isList x then
+                "[ ${concatItems (map toDhall x)} ]"
+              else if isString x || isPath x then
+                ''"${x}"''
+              else if isInt x then
+                "${if x < 0 then "" else "+"}${toString}"
+              else if isFloat x then
+                toString x
+              else if isBool x then
+                (if x then "True" else "False")
+              else
+                "abort generators.toDhall: unhandled value (${x})";
+          };
+
           nixosSystem =
             # A derivative of the function for generating Linux NixOS systems.
             # This one is not so well tested…