Phoenix template engine

lib/dsl/engine.ex

@@ -0,0 +1,42 @@
+defmodule Dsl.Engine do
+  @behaviour Phoenix.Template.Engine
+
+  def compile(path, _name) do
+    template =
+      path
+      |> File.read!()
+      |> Code.string_to_quoted!(file: path)
+      |> handle_assigns()
+
+    quote do
+      use Dsl
+
+      htm(do: unquote(template))
+    end
+  end
+
+  defp handle_assigns(quoted) do
+    quoted
+    |> Macro.prewalk(fn
+      {:@, _, [{key, _, _}]} ->
+        quote do
+          case Access.fetch(var!(assigns), unquote(key)) do
+            {:ok, val} ->
+              val
+
+            :error ->
+              raise ArgumentError, """
+              assign @#{unquote(key)} not available in Dsl template.
+              Please make sure all proper assigns have been set. If this
+              is a child template, ensure assigns are given explicitly by
+              the parent template as they are not automatically forwarded.
+              Available assigns: #{inspect(Enum.map(var!(assigns), &elem(&1, 0)))}
+              """
+          end
+        end
+
+      ast ->
+        ast
+    end)
+  end
+end

mix.exs

@@ -26,7 +26,9 @@ defmodule Dsl.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
-      {:phoenix_html, "~> 2.13"}
+      {:phoenix_html, "~> 2.13"},
+      {:phoenix, "~> 1.4", optional: true},
+      {:dialyxir, "~> 1.0.0-rc.6", only: [:dev], runtime: false}
     ]
   end
 end

mix.lock

@@ -1,6 +1,10 @@
 %{
+  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.6", "78e97d9c0ff1b5521dd68041193891aebebce52fc3b93463c0a6806874557d7d", [:mix], [{:erlex, "~> 0.2.1", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
+  "erlex": {:hex, :erlex, "0.2.1", "cee02918660807cbba9a7229cae9b42d1c6143b768c781fa6cee1eaf03ad860b", [:mix], [], "hexpm"},
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},
+  "phoenix": {:hex, :phoenix, "1.4.3", "8eed4a64ff1e12372cd634724bddd69185938f52c18e1396ebac76375d85677d", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 1.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 1.0 or ~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: true]}], "hexpm"},
   "phoenix_html": {:hex, :phoenix_html, "2.13.2", "f5d27c9b10ce881a60177d2b5227314fc60881e6b66b41dfe3349db6ed06cf57", [:mix], [{:plug, "~> 1.5", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "1.1.2", "496c303bdf1b2e98a9d26e89af5bba3ab487ba3a3735f74bf1f4064d2a845a3e", [:mix], [], "hexpm"},
   "plug": {:hex, :plug, "1.8.0", "9d2685cb007fe5e28ed9ac27af2815bc262b7817a00929ac10f56f169f43b977", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: true]}], "hexpm"},
   "plug_crypto": {:hex, :plug_crypto, "1.0.0", "18e49317d3fa343f24620ed22795ec29d4a5e602d52d1513ccea0b07d8ea7d4d", [:mix], [], "hexpm"},
 }