Inline collections (#283)

* allow Mongo.Collection's to be defined inline

* add some docs

Author: numso

lib/mongo/collection.ex

@@ -440,6 +440,28 @@ defmodule Mongo.Collection do
           "modified" : ISODate("2020-05-19T15:15:14.374Z"),
           "title" : "Vega"
         }
+
+  ## Example `Inlined Collections`
+
+  You can define an embedded collection inline. In the following example, the `Person.Friend`
+  and `Person.Pet` modules are automatically defined for you.
+
+        defmodule Person do
+          use Mongo.Collection
+
+          collection "persons" do
+            attribute :name, String.t()
+
+            embeds_one :friend, Friend do
+              attribute :name, String.t()
+            end
+
+            embeds_many :pets, Pet, default: [] do
+              attribute :name, String.t()
+            end
+          end
+        end
+
   ## Example `timestamps`
 
         defmodule Post do
@@ -879,8 +901,25 @@ defmodule Mongo.Collection do
   @doc """
   Adds the struct to the `embeds_one` list. Calls `__embeds_one__`
   """
-  defmacro embeds_one(name, mod, opts \\ []) do
+  defmacro embeds_one(name, mod, opts \\ [])
+
+  defmacro embeds_one(name, mod, do: block) do
+    quote do
+      embeds_one(unquote(name), unquote(mod), [], do: unquote(block))
+    end
+  end
+
+  defmacro embeds_one(name, mod, opts) do
+    quote do
+      Collection.__embeds_one__(__MODULE__, unquote(name), unquote(mod), unquote(opts))
+    end
+  end
+
+  defmacro embeds_one(name, mod, opts, do: block) do
+    mod = expand_nested_module_alias(mod, __CALLER__)
+
     quote do
+      Collection.__embeds_module__(__ENV__, unquote(mod), unquote(Macro.escape(block)))
       Collection.__embeds_one__(__MODULE__, unquote(name), unquote(mod), unquote(opts))
     end
   end
@@ -895,8 +934,26 @@ defmodule Mongo.Collection do
   @doc """
   Adds the struct to the `embeds_many` list. Calls `__embeds_many__`
   """
-  defmacro embeds_many(name, mod, opts \\ []) do
+  defmacro embeds_many(name, mod, opts \\ [])
+
+  defmacro embeds_many(name, mod, do: block) do
     quote do
+      embeds_many(unquote(name), unquote(mod), [], do: unquote(block))
+    end
+  end
+
+  defmacro embeds_many(name, mod, opts) do
+    quote do
+      type = unquote(Macro.escape({{:., [], [mod, :t]}, [], []}))
+      Collection.__embeds_many__(__MODULE__, unquote(name), unquote(mod), type, unquote(opts))
+    end
+  end
+
+  defmacro embeds_many(name, mod, opts, do: block) do
+    mod = expand_nested_module_alias(mod, __CALLER__)
+
+    quote do
+      Collection.__embeds_module__(__ENV__, unquote(mod), unquote(Macro.escape(block)))
       type = unquote(Macro.escape({{:., [], [mod, :t]}, [], []}))
       Collection.__embeds_many__(__MODULE__, unquote(name), unquote(mod), type, unquote(opts))
     end
@@ -910,6 +967,19 @@ defmodule Mongo.Collection do
     Module.put_attribute(mod, :embed_manys, {name, target, add_name(mod, opts, name)})
   end
 
+  def __embeds_module__(env, mod, block) do
+    block =
+      quote do
+        use Collection
+
+        document do
+          unquote(block)
+        end
+      end
+
+    Module.create(mod, block, env)
+  end
+
   @doc """
   Adds the attribute to the attributes list. It call `__attribute__/4` function.
   """
@@ -1080,4 +1150,12 @@ defmodule Mongo.Collection do
       |> Map.new()
     end
   end
+
+  defp expand_nested_module_alias({:__aliases__, _, [Elixir, _ | _] = alias}, _env),
+    do: Module.concat(alias)
+
+  defp expand_nested_module_alias({:__aliases__, _, [h | t]}, env) when is_atom(h),
+    do: Module.concat([env.module, h | t])
+
+  defp expand_nested_module_alias(other, _env), do: other
 end

test/collections/inlined_test.exs

@@ -0,0 +1,70 @@
+defmodule Collections.InlinedTest do
+  use MongoTest.Case, async: true
+
+  defmodule Person do
+    use Mongo.Collection
+
+    collection "persons" do
+      attribute :name, String.t(), default: "new name"
+
+      embeds_one :friend, Friend, default: &Person.Friend.new/0 do
+        attribute :name, String.t(), default: "new friend"
+      end
+
+      embeds_one :hobby, Hobby do
+        attribute :name, String.t()
+      end
+
+      embeds_many :pets, Pet, default: [] do
+        attribute :name, String.t(), default: "new pet"
+      end
+
+      embeds_many :things, Thing do
+        attribute :name, String.t()
+      end
+    end
+  end
+
+  test "created the appropriate modules", _c do
+    Code.ensure_compiled!(Person)
+    Code.ensure_compiled!(Person.Friend)
+    Code.ensure_compiled!(Person.Hobby)
+    Code.ensure_compiled!(Person.Pet)
+    Code.ensure_compiled!(Person.Thing)
+  end
+
+  test "can create a document for an inlined collection", _c do
+    new_person = %{
+      Person.new()
+      | friend: %{Person.Friend.new() | name: "new friend"},
+        hobby: %{Person.Hobby.new() | name: "new hobby"},
+        pets: [%{Person.Pet.new() | name: "new pet"}],
+        things: [%{Person.Thing.new() | name: "new thing"}]
+    }
+
+    map_person = Person.dump(new_person)
+    struct_person = Person.load(map_person, false)
+
+    assert %{
+             "name" => "new name",
+             "friend" => %{"name" => "new friend"},
+             "hobby" => %{"name" => "new hobby"},
+             "pets" => [%{"name" => "new pet"}],
+             "things" => [%{"name" => "new thing"}]
+           } = map_person
+
+    assert %Person{
+             name: "new name",
+             hobby: %Person.Hobby{name: "new hobby"},
+             friend: %Person.Friend{name: "new friend"},
+             things: [%Person.Thing{name: "new thing"}],
+             pets: [%Person.Pet{name: "new pet"}]
+           } = struct_person
+
+    new_person = Person.new()
+    map_person = Person.dump(new_person)
+    struct_person = Person.load(map_person, false)
+    assert %{"name" => "new name", "friend" => %{"name" => "new friend"}, "pets" => []} = map_person
+    assert %Person{name: "new name", friend: %Person.Friend{name: "new friend"}, pets: []} = struct_person
+  end
+end