From ddcb17f91fadf6006bcd74f292c5065162df8a83 Mon Sep 17 00:00:00 2001
From: Aleksei Matiushkin <aleksei.matiushkin@kantox.com>
Date: Sat, 1 Jul 2023 09:48:04 +0200
Subject: [PATCH] Example of `Listener` changing state

---
 lib/md/listener.ex | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/md/listener.ex b/lib/md/listener.ex
index 3e17ec3..b71ebba 100644
--- a/lib/md/listener.ex
+++ b/lib/md/listener.ex
@@ -118,3 +118,17 @@ defmodule Md.Listener.Debug do
   @moduledoc false
   use Md.Listener
 end
+
+defmodule Md.Listener.Beautifier do
+  @moduledoc false
+  use Md.Listener
+
+  alias Md.Parser.State
+
+  def handle_tag({:p, false}, %State{ast: [{:p, attrs, [title]}]} = state)
+      when byte_size(title) < 42 do
+    {:update, %State{state | ast: [{:h1, attrs, [title]}]}}
+  end
+
+  def handle_tag(_, _), do: :ok
+end