fix: resolve serialization errors in .NET examples (#37)

This ended up being a *slightly* bigger commit than I anticipated. But,
I essentially did two things:

- Annotate all `*Result` types in `Mondocks.Net/Types.fs` with
  `[<BsonIgnoreExtraElements>]`; otherwise, the .NET MongoDB Driver
  freaks out that the schema doesn't match exactly.

- Avoid serializing each `Index` object in the `IndexBuilder`.
  When I first ran the example in `samples/Indexes`, it failed with this
  exception:

  ```sh
  Unhandled exception. MongoDB.Driver.MongoCommandException: Command createIndexes failed: BSON field 'createIndexes.indexes.0' is the wrong type 'string', expected type 'object'.
  ```
  So we DON'T need the serialization step in the `IndexBuilder` anymore
  (though I kept the interface the same).

Finally, I added a Nix flake with a very simple `devShell` because
that's just what I'm used to developing with.

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "fantomas": {
-      "version": "5.1.3",
+      "version": "6.2.1",
       "commands": [
         "fantomas"
       ]

.gitignore

@@ -442,4 +442,7 @@ $RECYCLE.BIN/
 !.vscode/extensions.json
 
 *.fs.js
-*.mjs
+*.mjs
+
+# Direnv
+.envrc

flake.nix

@@ -0,0 +1,25 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+  };
+  outputs = { self, nixpkgs, flake-parts }@inputs:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      perSystem = { system, pkgs, ... }: {
+        # Basically "patches" the `pkgs` input to `perSystem`
+        _module.args.pkgs = import inputs.nixpkgs {
+          inherit system;
+          config.allowUnfreePredicate = pkg: builtins.elem (nixpkgs.lib.getName pkg) [ "mongodb" "mongodb-compass" ];
+        };
+        formatter = pkgs.nixfmt;
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs;
+            [ dotnet-sdk ];
+          shellHook = ''
+            dotnet tool restore
+          '';
+        };
+      };
+      systems = [ "x86_64-linux" "x86_64-darwin" "aarch64-darwin" ];
+    };
+}

src/Mondocks.Net/Mondocks.Net.fsproj

@@ -19,4 +19,4 @@
   <ItemGroup>
     <ProjectReference Include="..\Mondocks\Mondocks.fsproj" />
   </ItemGroup>
-</Project>
+</Project>

src/Mondocks.Net/Types.fs

@@ -1,15 +1,22 @@
 namespace Mondocks.Types
 
+open MongoDB.Bson
 open MongoDB.Bson.Serialization.Attributes
 
 [<BsonIgnoreExtraElements>]
 type Cursor<'T> = { firstBatch: seq<'T>; ns: string }
 
+[<BsonIgnoreExtraElements>]
 type FindResult<'T> = { cursor: Cursor<'T>; ok: float }
 
 [<BsonIgnoreExtraElements>]
 type InsertResult = { n: int; ok: float }
 
+[<BsonIgnoreExtraElements>]
+type UpdateResult = { n: int; nModified: int; ok: float }
+
+[<BsonIgnoreExtraElements>]
+type DeleteResult = { n: int; ok: float }
 
 [<BsonIgnoreExtraElements>]
 type CreateIndexResult =

src/Mondocks/Database.fs

@@ -68,7 +68,7 @@ type IndexBuilder(name: string, serialize: SerializerFn) =
           wildcardProjection = None }
 
     member inline this.Run(state: Index<'PartialFilterExpression, 'StorageEngine, 'Weights, 'WildcardProjection>) =
-        this.Serialize { state with name = this.Name }
+        { state with name = this.Name }
 
     [<CustomOperation("key")>]
     member inline __.Key