Deprecate binary content in XML encoder

lib/saxy.ex

@@ -82,7 +82,7 @@ defmodule Saxy do
 
       iex> import Saxy.XML
       iex> element = element("person", [gender: "female"], "Alice")
-      {"person", [{"gender", "female"}], ["Alice"]}
+      {"person", [{"gender", "female"}], [{:characters, "Alice"}]}
       iex> Saxy.encode!(element, [version: "1.0"])
       "<?xml version=\"1.0\"?><person gender=\"female\">Alice</person>"
 

lib/saxy/builder.ex

@@ -22,7 +22,7 @@ defprotocol Saxy.Builder do
 
       iex> person = %Person{name: "Alice", gender: "female"}
       iex> Saxy.Builder.build(person)
-      {"person", [{"gender", "female"}], ["Alice"]}
+      {"person", [{"gender", "female"}], [{:characters, "Alice"}]}
 
   Custom implementation could be done by implementing protocol:
 
@@ -44,7 +44,7 @@ defprotocol Saxy.Builder do
 
       iex> user = %User{name: "Alice", username: "alice99"}
       iex> Saxy.Builder.build(user)
-      {"Person", [{"userName", "alice99"}], [{"Name", [], ["Alice"]}]}
+      {"Person", [{"userName", "alice99"}], [{"Name", [], [{:characters, "Alice"}]}]}
   """
 
   @doc """

lib/saxy/encoder.ex

@@ -82,6 +82,12 @@ defmodule Saxy.Encoder do
   end
 
   defp content([characters | elements]) when is_binary(characters) do
+    IO.warn("""
+    Passing binary as :characters content is derepcated and will be removed in future versions.
+
+    Please wrap the binary with Saxy.XML.characters/1.
+    """)
+
     [characters | content(elements)]
   end
 

lib/saxy/xml.ex

@@ -148,7 +148,7 @@ defmodule Saxy.XML do
   defp children(children, acc \\ [])
 
   defp children([binary | children], acc) when is_binary(binary) do
-    children(children, [binary | acc])
+    children(children, [characters(binary) | acc])
   end
 
   defp children([{type, _} = form | children], acc)

test/saxy/builder_test.exs

@@ -54,11 +54,11 @@ defmodule Saxy.BuilderTest do
 
   test "builds element from struct" do
     struct = %Struct{foo: "foo", bar: "bar"}
-    assert build(struct) == {"test", [{"foo", "foo"}], ["bar"]}
+    assert build(struct) == {"test", [{"foo", "foo"}], [{:characters, "bar"}]}
 
     nested_struct = %Struct{bar: struct}
 
-    assert build(nested_struct) == {"test", [{"foo", ""}], [{"test", [{"foo", "foo"}], ["bar"]}]}
+    assert build(nested_struct) == {"test", [{"foo", ""}], [{"test", [{"foo", "foo"}], [{:characters, "bar"}]}]}
 
     underived_struct = %UnderivedStruct{}
     assert_raise Protocol.UndefinedError, fn -> build(underived_struct) end