Introduce "Saxy.encode!/2" and "Saxy.encode_to_iodata!/2"

lib/saxy.ex

@@ -57,7 +57,11 @@ defmodule Saxy do
 
   """
 
-  alias Saxy.{Parser, State}
+  alias Saxy.{
+    Encoder,
+    Parser,
+    State
+  }
 
   @doc ~S"""
   Parses XML binary data.
@@ -206,4 +210,53 @@ defmodule Saxy do
 
     Parser.parse_document(<<>>, stream, state)
   end
+
+  @doc """
+  Encodes a simple form XML element into string.
+
+  This function encodes an element in simple form format and a prolog to an XML document.
+
+  ## Examples
+
+      iex> import Saxy.XML
+      iex> root = element(:foo, [{"foo", "bar"}], "bar")
+      iex> prolog = [version: "1.0"]
+      iex> Saxy.encode!(root, prolog)
+      "<?xml version=\\"1.0\\"?><foo foo=\\"bar\\">bar</foo>"
+
+  """
+
+  @spec encode!(root :: Saxy.XML.element(), prolog :: Saxy.Prolog.t() | Keyword.t()) :: String.t()
+
+  def encode!(root, prolog \\ []) do
+    root
+    |> Encoder.encode_to_iodata(prolog)
+    |> IO.iodata_to_binary()
+  end
+
+  @doc """
+  Encodes a simple form element into IO data.
+
+  Same as `encode!/2` but this encodes the document into IO data.
+
+  ## Examples
+
+      iex> import Saxy.XML
+      iex> root = element(:foo, [{"foo", "bar"}], "bar")
+      iex> prolog = [version: "1.0"]
+      iex> Saxy.encode_to_iodata!(root, prolog)
+      [
+        ['<?xml', [32, 'version', 61, 34, "1.0", 34], [], [], '?>'],
+        [60, "foo", 32, "foo", 61, 34, "bar", 34],
+        62,
+        ["bar"],
+        [60, 47, "foo", 62]
+      ]
+
+  """
+  @spec encode_to_iodata!(root :: Saxy.XML.element(), prolog :: Saxy.Prolog.t() | Keyword.t()) :: iodata()
+
+  def encode_to_iodata!(root, prolog \\ []) do
+    Encoder.encode_to_iodata(root, prolog)
+  end
 end

test/saxy_test.exs

@@ -109,5 +109,25 @@ defmodule SaxyTest do
     assert HandlerError.message(error) == "unexpected return :something_wrong in :start_document event handler"
   end
 
+  describe "encode!/2" do
+    import Saxy.XML
+
+    test "encodes XML document into string" do
+      root = element("foo", [], "foo")
+      assert Saxy.encode!(root) == ~s(<?xml version="1.0"?><foo>foo</foo>)
+    end
+  end
+
+  describe "encode_to_iodata!/2" do
+    import Saxy.XML
+
+    test "encodes XML document into IO data" do
+      root = element("foo", [], "foo")
+      assert xml = Saxy.encode_to_iodata!(root)
+      assert is_list(xml)
+      assert IO.iodata_to_binary(xml) == ~s(<?xml version="1.0"?><foo>foo</foo>)
+    end
+  end
+
   def convert_entity("unknown"), do: "known"
 end