Add Kino.nothing/0

lib/kino.ex

@@ -96,18 +96,20 @@ defmodule Kino do
   `inspect/2`.
   '''
 
+  @type nothing :: :"do not show this result in output"
+
   @doc """
   Sends the given term as cell output.
 
   This allows any Livebook cell to have multiple evaluation
   results. You can think of this function as a generalized
   `IO.puts/2` that works for any type.
   """
-  @spec render(term()) :: :"do not show this result in output"
+  @spec render(term()) :: nothing()
   def render(term) do
     output = Kino.Render.to_livebook(term)
     Kino.Bridge.put_output(output)
-    :"do not show this result in output"
+    nothing()
   end
 
   @doc """
@@ -166,7 +168,7 @@ defmodule Kino do
           pos_integer(),
           term(),
           (term() -> {:cont, term(), acc :: term()} | :halt)
-        ) :: :"do not show this result in output"
+        ) :: nothing()
   def animate(interval_ms, acc, fun) do
     widget = Kino.Frame.new()
 
@@ -183,4 +185,12 @@ defmodule Kino do
 
     Kino.render(widget)
   end
+
+  @doc """
+  Returns a special value that results in no visible output.
+  """
+  @spec nothing() :: atom()
+  def nothing() do
+    :"do not show this result in output"
+  end
 end