Autorunner

lib/display.ex

@@ -0,0 +1,44 @@
+defmodule Display do
+  alias IO.ANSI
+  @current_dir File.cwd!
+
+  def show_failure(%{expr: expr}, module, name) do
+    IO.puts("")
+    IO.puts("Now meditate upon #{display_module(module)}")
+    IO.puts("---------------------------------------")
+    IO.puts("Assertion failed in #{source_file(module)}:#{line_number(expr)}")
+    IO.puts(display_koan(name))
+    IO.puts(format_red(Macro.to_string(expr)))
+  end
+
+  def considering(module) do
+    IO.puts("Considering #{display_module(module)}...")
+  end
+
+  def before_run do
+    IO.puts("")
+    IO.puts("")
+  end
+
+  defp line_number({_, [line: line], _}) do
+    line
+  end
+
+  defp source_file(module) do
+    module.__info__(:compile)
+    |> Dict.get(:source)
+    |> Path.relative_to(@current_dir)
+  end
+
+  defp format_red(str) do
+    Enum.join([ANSI.red, str, ANSI.reset], "")
+  end
+
+  defp display_module(module) do
+    Module.split(module) |> List.last
+  end
+
+  defp display_koan(name) do
+    String.replace(to_string(name), Koans.prefix, "")
+  end
+end

lib/koans.ex

@@ -1,6 +1,8 @@
 defmodule Koans do
+  @prefix "koan: "
+
   defmacro koan(name, body) do
-    compiled_name = :"koan: #{name}"
+    compiled_name = :"#{prefix}#{name}"
     quote do
       def unquote(compiled_name)() do
         try do
@@ -19,4 +21,8 @@ defmodule Koans do
       import ExUnit.Assertions
     end
   end
+
+  def prefix do
+    @prefix
+  end
 end

lib/meditate.ex

@@ -2,7 +2,11 @@ defmodule Mix.Tasks.Meditate do
   use Mix.Task
 
   def run(_) do
+    Application.ensure_all_started(:elixir_koans)
+    Code.compiler_options(ignore_module_conflict: true)
+    Watcher.start
     Runner.run
+    :timer.sleep(:infinity)
   end
 end
 

lib/runner.ex

@@ -1,31 +1,32 @@
 defmodule Runner do
-  alias IO.ANSI
-
   @modules [
     Equalities,
     Lists
   ]
 
   def run do
-    IO.puts("")
-    Enum.take_while(@modules, fn(mod) ->
+    run(Equalities)
+  end
+
+  def run(start_module) do
+    Display.before_run
+
+    start_idx = Enum.find_index(@modules, &(&1 == start_module))
+    Enum.drop(@modules, start_idx)
+    |> Enum.take_while(fn(mod) ->
       run_module(mod) == :passed
     end)
   end
 
   def run_module(module) do
-    IO.puts("Considering #{display_module(module)}...")
+    Display.considering(module)
 
-    functions = module.__info__(:functions)
-
-    koans = Enum.map(functions, fn({name, _arity}) -> name end)
-    |> Enum.filter(&koan?/1)
+    koans = extract_koans_from(module)
 
     passed = Enum.take_while(koans, fn(name) ->
       run_koan(module, name) == :passed
     end)
 
-
     if Enum.count(koans) == Enum.count(passed) do
       :passed
     else
@@ -37,33 +38,18 @@ defmodule Runner do
     case apply(module, name, []) do
       :ok   -> :passed
       error ->
-        show_failure(error, module, name)
+        Display.show_failure(error, module, name)
         :failed
     end
   end
 
-  def show_failure(%{expr: expr}, module, name) do
-    IO.puts("")
-    IO.puts("Now meditate upon #{display_module(module)}")
-    IO.puts("---------------------------------------")
-    IO.puts("Assertion failed!")
-    IO.puts(display_koan(name))
-    IO.puts(format_red(Macro.to_string(expr)))
-  end
-
-  def format_red(str) do
-    Enum.join([ANSI.red, str, ANSI.reset], "")
+  defp extract_koans_from(module) do
+    module.__info__(:functions)
+    |> Enum.map(fn({name, _arity}) -> name end)
+    |> Enum.filter(&koan?/1)
   end
 
   defp koan?(fun_name) do
-    String.starts_with?(to_string(fun_name), "koan: ")
-  end
-
-  defp display_module(module) do
-    Module.split(module) |> List.last
-  end
-
-  defp display_koan(name) do
-    String.replace(to_string(name), "koan: ", "")
+    String.starts_with?(to_string(fun_name), Koans.prefix)
   end
 end

lib/watcher.ex

@@ -0,0 +1,10 @@
+defmodule Watcher do
+  use ExFSWatch, dirs: ["lib/koans"]
+
+  def callback(file, events)  do
+    if Enum.member?(events, :modified) do
+      [{mod, _}] = Code.load_file(file)
+      Runner.run(mod)
+    end
+  end
+end

mix.exs

@@ -9,7 +9,7 @@ defmodule Koans.Mixfile do
   end
 
   def application do
-    [applications: [:logger]]
+    [applications: [:exfswatch, :logger]]
   end
 
   defp deps do