From f09f9d8edf4621807f113b128f5f733c912f4e3c Mon Sep 17 00:00:00 2001
From: Daniel Flanagan <daniel@lytedev.io>
Date: Sat, 11 May 2019 14:00:46 -0500
Subject: [PATCH] WIP parsing

---
 lib/lytlang.ex        | 18 +++++----
 lib/transpiler.ex     | 93 +++++++++++++++++++++++++++++++++++++++++++
 test/lytlang_test.exs | 20 +---------
 3 files changed, 104 insertions(+), 27 deletions(-)
 create mode 100644 lib/transpiler.ex

diff --git a/lib/lytlang.ex b/lib/lytlang.ex
index 053f300..096e138 100644
--- a/lib/lytlang.ex
+++ b/lib/lytlang.ex
@@ -16,14 +16,16 @@ defmodule Lytlang do
     :world
   end
 
-  @spec transpile_file(String.t()) :: String.t()
-  def transpile_file(file_path) do
-    file_path
-    |> File.read!()
-    |> transpile_block()
-  end
+  @doc """
+  Echo.
 
-  def transpile_block(s) do
-    "#{s}"
+  ## Examples
+
+      iex> Lytlang.echo("world")
+      "world"
+
+  """
+  def echo(s) do
+    s
   end
 end
diff --git a/lib/transpiler.ex b/lib/transpiler.ex
new file mode 100644
index 0000000..b83acbc
--- /dev/null
+++ b/lib/transpiler.ex
@@ -0,0 +1,93 @@
+defmodule Lytlang.Transpiler do
+  @moduledoc """
+  Documentation for Lytlang.
+  """
+
+  @spec transpile_file(String.t()) :: String.t()
+  def transpile_file(file_path) do
+    file_path
+    |> File.read!()
+    |> transpile_block()
+  end
+
+  @doc """
+  Transpiler!
+
+  ## Examples
+
+      iex> Lytlang.Transpiler.transpile_block("!mod EmptyModule")
+      "defmodule EmptyModule do\\nend"
+
+      iex> Lytlang.Transpiler.transpile_block("!mod EmptyModule\\n\\tfn hello\\n\\t\\t:world")
+      "defmodule EmptyModule\\n\\tdef hello() do\\n\\t\\t:world\\n\\tend\\nend"
+
+  """
+  @spec transpile_block(String.t(), Keyword.t()) :: String.t()
+  def transpile_block(s, _opts \\ []) do
+    s
+    |> split_lines()
+    |> Enum.map(&tokenize/1)
+    |> IO.inspect(label: "Tokens")
+    |> build_ast()
+    |> IO.inspect(label: "AST")
+    |> ast_to_elixir()
+  end
+
+  def initial_ast_state() do
+    %{
+      ast: {:__global, []}
+    }
+  end
+
+  def build_ast(token_lines, state \\ nil)
+
+  def build_ast([], state), do: state.ast |> Enum.reverse()
+
+  def build_ast([line_tokens | rest], state) do
+    state =
+      if !state do
+        initial_ast_state()
+      else
+        state
+      end
+
+    ast = state.ast
+
+    state =
+      case line_tokens do
+        ["!mod", module_name | rest] ->
+          %{state | ast: [{:module, String.to_atom(module_name), []} | ast]}
+
+        ["fn", fn_name | rest] ->
+          %{state | ast: [{:function, String.to_atom(fn_name), []} | ast]}
+
+        expr ->
+          expr |> IO.inspect(label: "lyt expression")
+          %{state | ast: [expr |> Enum.join(" ") | ast]}
+      end
+
+    build_ast(rest, state)
+  end
+
+  def ast_to_elixir([], state),
+    do: state.elixir_code |> Enum.filter(&(String.trim(&1) != "")) |> Enum.join("\n")
+
+  def ast_to_elixir([leaf | rest], state \\ %{elixir_code: []}) do
+    child = fn {head, tail}, state -> [head | ast_to_elixir(rest, state)] ++ [tail] end
+
+    case leaf do
+      :global -> child.({"", ""}, state)
+      {:module, mod, []} -> child.({"defmodule #{to_string(mod)} do", "end"}, state)
+      {:fn, fname, []} -> child.({"def #{to_string(fname)} do", "end"}, state)
+      expr when is_binary(expr) -> [expr]
+    end
+  end
+
+  def split_lines(s) do
+    String.split(s, "\n", trim: true)
+  end
+
+  def tokenize(s) do
+    Regex.split(~r/\s/, s, true)
+  end
+end
diff --git a/test/lytlang_test.exs b/test/lytlang_test.exs
index 779aee4..d376b88 100644
--- a/test/lytlang_test.exs
+++ b/test/lytlang_test.exs
@@ -1,27 +1,9 @@
 defmodule LytlangTest do
   use ExUnit.Case
   doctest Lytlang
+  doctest Lytlang.Transpiler
 
   test "greets the world" do
     assert Lytlang.hello() == :world
   end
-
-  test "transpiles module" do
-    input = """
-    !mod EmptyModule
-    """
-
-    output = """
-    defmodule EmptyModule
-    end
-    """
-
-    assert Lytlang.transpile_block(input) == output
-  end
-
-  @tag :skip
-  test "transpiles example tiny module file correctly" do
-    output = File.read!("./test/fixtures/tiny.exs")
-    assert Lytlang.transpile_file("./test/fixtures/tiny.lyt") == output
-  end
 end