Add optional function annotations (#1627)

lib/ex_doc/config.ex

@@ -6,8 +6,10 @@ defmodule ExDoc.Config do
   def filter_modules(_module, _metadata), do: true
   def before_closing_head_tag(_), do: ""
   def before_closing_body_tag(_), do: ""
+  def annotations_for_docs(_), do: []
 
-  defstruct api_reference: true,
+  defstruct annotations_for_docs: &__MODULE__.annotations_for_docs/1,
+            api_reference: true,
             apps: [],
             assets: nil,
             authors: nil,
@@ -44,6 +46,7 @@ defmodule ExDoc.Config do
             version: nil
 
   @type t :: %__MODULE__{
+          annotations_for_docs: (map() -> list()),
           api_reference: boolean(),
           apps: [atom()],
           assets: nil | String.t(),

lib/ex_doc/retriever.ex

@@ -108,9 +108,15 @@ defmodule ExDoc.Retriever do
       config.groups_for_functions ++
         [Callbacks: &(&1[:__doc__] == :callback), Functions: fn _ -> true end]
 
+    annotations_for_docs = config.annotations_for_docs
+
     docs_groups = Enum.map(groups_for_functions, &elem(&1, 0))
-    function_docs = get_docs(module_data, source, groups_for_functions)
-    docs = function_docs ++ get_callbacks(module_data, source, groups_for_functions)
+    function_docs = get_docs(module_data, source, groups_for_functions, annotations_for_docs)
+
+    docs =
+      function_docs ++
+        get_callbacks(module_data, source, groups_for_functions, annotations_for_docs)
+
     types = get_types(module_data, source)
 
     metadata = Map.put(metadata, :__doc__, module_data.type)
@@ -157,7 +163,7 @@ defmodule ExDoc.Retriever do
 
   ## Function helpers
 
-  defp get_docs(module_data, source, groups_for_functions) do
+  defp get_docs(module_data, source, groups_for_functions, annotations_for_docs) do
     {:docs_v1, _, _, _, _, _, doc_elements} = module_data.docs
 
     nodes =
@@ -167,18 +173,38 @@ defmodule ExDoc.Retriever do
             []
 
           function_data ->
-            [get_function(doc_element, function_data, source, module_data, groups_for_functions)]
+            [
+              get_function(
+                doc_element,
+                function_data,
+                source,
+                module_data,
+                groups_for_functions,
+                annotations_for_docs
+              )
+            ]
         end
       end)
 
     filter_defaults(nodes)
   end
 
-  defp get_function(doc_element, function_data, source, module_data, groups_for_functions) do
+  defp get_function(
+         doc_element,
+         function_data,
+         source,
+         module_data,
+         groups_for_functions,
+         annotations_for_docs
+       ) do
     {:docs_v1, _, _, content_type, _, _, _} = module_data.docs
     {{type, name, arity}, anno, signature, doc_content, metadata} = doc_element
     doc_line = anno_line(anno)
-    annotations = annotations_from_metadata(metadata) ++ function_data.extra_annotations
+
+    annotations =
+      annotations_for_docs.(metadata) ++
+        annotations_from_metadata(metadata) ++ function_data.extra_annotations
+
     line = function_data.line || doc_line
     defaults = get_defaults(name, arity, Map.get(metadata, :defaults, 0))
 
@@ -226,17 +252,22 @@ defmodule ExDoc.Retriever do
 
   ## Callback helpers
 
-  defp get_callbacks(%{type: :behaviour} = module_data, source, groups_for_functions) do
+  defp get_callbacks(
+         %{type: :behaviour} = module_data,
+         source,
+         groups_for_functions,
+         annotations_for_docs
+       ) do
     {:docs_v1, _, _, _, _, _, docs} = module_data.docs
 
     for {{kind, _, _}, _, _, _, _} = doc <- docs, kind in module_data.callback_types do
-      get_callback(doc, source, groups_for_functions, module_data)
+      get_callback(doc, source, groups_for_functions, module_data, annotations_for_docs)
     end
   end
 
-  defp get_callbacks(_, _, _), do: []
+  defp get_callbacks(_, _, _, _), do: []
 
-  defp get_callback(callback, source, groups_for_functions, module_data) do
+  defp get_callback(callback, source, groups_for_functions, module_data, annotations_for_docs) do
     callback_data = module_data.language.callback_data(callback, module_data)
 
     {:docs_v1, _, _, content_type, _, _, _} = module_data.docs
@@ -245,7 +276,11 @@ defmodule ExDoc.Retriever do
 
     signature = signature(callback_data.signature)
     specs = callback_data.specs
-    annotations = callback_data.extra_annotations ++ annotations_from_metadata(metadata)
+
+    annotations =
+      annotations_for_docs.(metadata) ++
+        callback_data.extra_annotations ++ annotations_from_metadata(metadata)
+
     doc_ast = doc_ast(content_type, doc, file: source.path, line: doc_line + 1)
 
     metadata = Map.put(metadata, :__doc__, :callback)

test/ex_doc/retriever_test.exs

@@ -91,6 +91,57 @@ defmodule ExDoc.RetrieverTest do
       assert %{id: "baz/0", group: :"Group 2"} = baz
     end
 
+    test "custom function annotations", c do
+      elixirc(c, ~S"""
+      defmodule A do
+        @doc since: "1.0.0"
+        @doc deprecated: "deprecation message"
+        @doc foo: true
+        def foo(), do: :ok
+      end
+      """)
+
+      [mod] =
+        Retriever.docs_from_modules([A], %ExDoc.Config{
+          annotations_for_docs: fn metadata ->
+            if metadata[:foo] do
+              [:baz]
+            else
+              []
+            end
+          end
+        })
+
+      [foo] = mod.docs
+      assert foo.id == "foo/0"
+      assert foo.annotations == [:baz, "since 1.0.0"]
+      assert foo.deprecated == "deprecation message"
+    end
+
+    test "custom callback annotations", c do
+      elixirc(c, ~S"""
+      defmodule A do
+        @doc foo: true
+        @callback callback_name() :: :ok
+      end
+      """)
+
+      [mod] =
+        Retriever.docs_from_modules([A], %ExDoc.Config{
+          annotations_for_docs: fn metadata ->
+            if metadata[:foo] do
+              [:baz]
+            else
+              []
+            end
+          end
+        })
+
+      [foo] = mod.docs
+
+      assert foo.annotations == [:baz]
+    end
+
     test "nesting", c do
       elixirc(c, ~S"""
       defmodule Nesting.Prefix.B.A do