From 89dac5bb05f5fca6bc7732535f75d6b29a5bd40a Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Sun, 13 Mar 2016 14:56:43 +0000
Subject: [PATCH 1/6] ASTMangler supports multiple placeholders

---
 lib/ast_mangler.ex        | 23 ++++++++++++++++++++---
 test/ast_mangler_test.exs | 18 ++++++++++++++++++
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/lib/ast_mangler.ex b/lib/ast_mangler.ex
index eed4281..ac5f253 100644
--- a/lib/ast_mangler.ex
+++ b/lib/ast_mangler.ex
@@ -1,8 +1,25 @@
 defmodule ASTMangler do
+
+  def expand([do: remainder], replacements) when is_list(replacements) do
+    [do: expand(remainder, replacements)]
+  end
+  def expand(ast, replacements) when is_list(replacements) do
+    {node, _acc} = Macro.prewalk(ast, replacements, fn(node, acc) -> pre(node, acc) end)
+    node
+  end
   def expand(ast, replacement) do
-    Macro.prewalk(ast, fn(node) -> update(node, replacement) end)
+    expand(ast, [replacement])
   end
 
-  def update(:__, replacement), do: replacement
-  def update(node, _), do: node
+  def pre(:__, [first | remainder]), do: {first, remainder}
+  def pre(node, acc), do: {node, acc}
+
+
+  def count(ast) do
+    {_node, acc} = Macro.prewalk(ast, 0, fn(node, acc) -> count(node, acc) end)
+    acc
+  end
+
+  def count(:__, acc), do: {node, acc+1}
+  def count(node, acc), do: {node, acc}
 end
diff --git a/test/ast_mangler_test.exs b/test/ast_mangler_test.exs
index 9cb66b7..223fdec 100644
--- a/test/ast_mangler_test.exs
+++ b/test/ast_mangler_test.exs
@@ -28,4 +28,22 @@ defmodule ASTManglerTest do
 
     assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, true]}]}] == ASTMangler.expand(ast, true)
   end
+
+  test "multiple arguments" do
+    ast = [do: {:assert, [line: 5], [{:==, [line: 5], [:__, :__]}]}]
+
+    assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, false]}]}] == ASTMangler.expand(ast, [true, false])
+  end
+
+  test "counts simple blanks" do
+    ast = quote do: 1 + :__
+
+    assert ASTMangler.count(ast) == 1
+  end
+
+  test "counts multiple blanks" do
+    ast = [do: {:assert, [line: 5], [{:==, [line: 5], [:__, :__]}]}]
+
+    assert ASTMangler.count(ast) == 2
+  end
 end

From 4897527dab4d329a6c399be4c9d25698b8d47cd4 Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Thu, 17 Mar 2016 23:13:35 +0000
Subject: [PATCH 2/6] Use a tuple to get indexed access to a arguments

---
 lib/koans.ex              | 10 ++++++++--
 test/ast_mangler_test.exs |  5 +++++
 test/sample_koan_test.exs |  8 ++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 test/sample_koan_test.exs

diff --git a/lib/koans.ex b/lib/koans.ex
index c313581..9331728 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -1,7 +1,8 @@
 defmodule Koans do
   defmacro koan(name, body) do
     compiled_name = String.to_atom(name)
-    mangled_body = ASTMangler.expand(body, quote do: answer)
+    expanded_answers = expand(ASTMangler.count(body))
+    mangled_body = ASTMangler.expand(body, expanded_answers)
     quote do
       @koans unquote(compiled_name)
       def unquote(compiled_name)() do
@@ -13,13 +14,18 @@ defmodule Koans do
         end
       end
 
-      def unquote(compiled_name)(answer) do
+      def unquote(compiled_name)(answer) when is_list(answer) do
+        converted = List.to_tuple(answer)
         unquote(mangled_body)
         :ok
       end
     end
   end
 
+  def expand(amount) do
+    Enum.map(0..amount, fn (idx) -> {:elem, [context: Koans, import: Kernel], [{:converted, [], Koans}, idx]} end)
+  end
+
   defmacro __using__(_opts) do
     quote do
       @compile :nowarn_unused_vars
diff --git a/test/ast_mangler_test.exs b/test/ast_mangler_test.exs
index 223fdec..4478ac4 100644
--- a/test/ast_mangler_test.exs
+++ b/test/ast_mangler_test.exs
@@ -8,6 +8,11 @@ defmodule ASTManglerTest do
     assert {:+, [context: ASTManglerTest, import: Kernel], [1, 37]} == mangled
   end
 
+  test "Work with multiple different replacements" do
+    [koan | _] = SampleKoan.all_koans
+    assert :ok == apply(SampleKoan, koan, [{:multiple, [3,4]}])
+  end
+
   def complex_example do
     [head | tail] = [1,2,3,4]
 
diff --git a/test/sample_koan_test.exs b/test/sample_koan_test.exs
new file mode 100644
index 0000000..d48e340
--- /dev/null
+++ b/test/sample_koan_test.exs
@@ -0,0 +1,8 @@
+defmodule SampleKoan do
+  use Koans
+
+  koan "thinking more than once" do
+    assert 3 == :__
+    assert 4 == :__
+  end
+end

From 023bb62e015f4ff28155af0fee25dee13194cb5f Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Fri, 18 Mar 2016 12:46:13 +0000
Subject: [PATCH 3/6] Generate test methods depending on the number of
 arguments.

---
 lib/koans.ex | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/koans.ex b/lib/koans.ex
index 9331728..32fdb4d 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -1,10 +1,12 @@
 defmodule Koans do
   defmacro koan(name, body) do
     compiled_name = String.to_atom(name)
-    expanded_answers = expand(ASTMangler.count(body))
-    mangled_body = ASTMangler.expand(body, expanded_answers)
+    number_of_args = ASTMangler.count(body)
     quote do
       @koans unquote(compiled_name)
+
+      generate_test_method(unquote(compiled_name), unquote(number_of_args), unquote(body))
+
       def unquote(compiled_name)() do
         try do
           unquote(body)
@@ -13,17 +15,34 @@ defmodule Koans do
           e in _ -> e
         end
       end
+    end
+  end
 
-      def unquote(compiled_name)(answer) when is_list(answer) do
-        converted = List.to_tuple(answer)
-        unquote(mangled_body)
+  defmacro generate_test_method(_name, 0, _body), do: false
+  defmacro generate_test_method(name, 1, body) do
+    single_var = ASTMangler.expand(body, Macro.var(:answer, Koans))
+    quote do
+      def unquote(name)(answer) do
+        converted = {answer}
+        unquote(single_var)
+        :ok
+      end
+    end
+  end
+  defmacro generate_test_method(name, number_of_args, body) do
+    answer_placeholders = expand(number_of_args)
+    multi_var = ASTMangler.expand(body, answer_placeholders)
+    quote do
+      def unquote(name)({:multiple, answers}) do
+        converted = List.to_tuple(answers)
+        unquote(multi_var)
         :ok
       end
     end
   end
 
   def expand(amount) do
-    Enum.map(0..amount, fn (idx) -> {:elem, [context: Koans, import: Kernel], [{:converted, [], Koans}, idx]} end)
+    Enum.map(0..amount, fn (idx) -> quote do: elem(converted, unquote(idx)) end)
   end
 
   defmacro __using__(_opts) do

From 994579f4974a07c5014d2c50bda1f4522b0e762a Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Sun, 20 Mar 2016 19:18:26 +0000
Subject: [PATCH 4/6] Rename and clean the ASTMangler to Blanks

---
 lib/ast_mangler.ex                            | 25 -------------------
 lib/blanks.ex                                 | 21 ++++++++++++++++
 lib/koans.ex                                  | 10 ++++----
 .../{ast_mangler_test.exs => blanks_test.exs} | 14 +++++------
 4 files changed, 33 insertions(+), 37 deletions(-)
 delete mode 100644 lib/ast_mangler.ex
 create mode 100644 lib/blanks.ex
 rename test/{ast_mangler_test.exs => blanks_test.exs} (75%)

diff --git a/lib/ast_mangler.ex b/lib/ast_mangler.ex
deleted file mode 100644
index ac5f253..0000000
--- a/lib/ast_mangler.ex
+++ /dev/null
@@ -1,25 +0,0 @@
-defmodule ASTMangler do
-
-  def expand([do: remainder], replacements) when is_list(replacements) do
-    [do: expand(remainder, replacements)]
-  end
-  def expand(ast, replacements) when is_list(replacements) do
-    {node, _acc} = Macro.prewalk(ast, replacements, fn(node, acc) -> pre(node, acc) end)
-    node
-  end
-  def expand(ast, replacement) do
-    expand(ast, [replacement])
-  end
-
-  def pre(:__, [first | remainder]), do: {first, remainder}
-  def pre(node, acc), do: {node, acc}
-
-
-  def count(ast) do
-    {_node, acc} = Macro.prewalk(ast, 0, fn(node, acc) -> count(node, acc) end)
-    acc
-  end
-
-  def count(:__, acc), do: {node, acc+1}
-  def count(node, acc), do: {node, acc}
-end
diff --git a/lib/blanks.ex b/lib/blanks.ex
new file mode 100644
index 0000000..248803f
--- /dev/null
+++ b/lib/blanks.ex
@@ -0,0 +1,21 @@
+defmodule Blanks do
+  def replace(ast, replacement) when not is_list(replacement), do: replace(ast, [replacement])
+  def replace([do: ast], replacements), do: [do: replace(ast, replacements)]
+  def replace(ast, replacements) do
+    ast
+    |> Macro.prewalk(replacements, &pre/2)
+    |> elem(0)
+  end
+
+  def pre(:__, [first | remainder]), do: {first, remainder}
+  def pre(node, acc), do: {node, acc}
+
+  def count(ast) do
+    ast
+    |> Macro.prewalk(0, &count/2)
+    |> elem(1)
+  end
+
+  def count(:__, acc), do: {node, acc+1}
+  def count(node, acc), do: {node, acc}
+end
diff --git a/lib/koans.ex b/lib/koans.ex
index 32fdb4d..f54514e 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -1,7 +1,7 @@
 defmodule Koans do
   defmacro koan(name, body) do
     compiled_name = String.to_atom(name)
-    number_of_args = ASTMangler.count(body)
+    number_of_args = Blanks.count(body)
     quote do
       @koans unquote(compiled_name)
 
@@ -20,7 +20,7 @@ defmodule Koans do
 
   defmacro generate_test_method(_name, 0, _body), do: false
   defmacro generate_test_method(name, 1, body) do
-    single_var = ASTMangler.expand(body, Macro.var(:answer, Koans))
+    single_var = Blanks.replace(body, Macro.var(:answer, Koans))
     quote do
       def unquote(name)(answer) do
         converted = {answer}
@@ -30,8 +30,8 @@ defmodule Koans do
     end
   end
   defmacro generate_test_method(name, number_of_args, body) do
-    answer_placeholders = expand(number_of_args)
-    multi_var = ASTMangler.expand(body, answer_placeholders)
+    answer_placeholders = create_vars(number_of_args)
+    multi_var = Blanks.replace(body, answer_placeholders)
     quote do
       def unquote(name)({:multiple, answers}) do
         converted = List.to_tuple(answers)
@@ -41,7 +41,7 @@ defmodule Koans do
     end
   end
 
-  def expand(amount) do
+  def create_vars(amount) do
     Enum.map(0..amount, fn (idx) -> quote do: elem(converted, unquote(idx)) end)
   end
 
diff --git a/test/ast_mangler_test.exs b/test/blanks_test.exs
similarity index 75%
rename from test/ast_mangler_test.exs
rename to test/blanks_test.exs
index 4478ac4..9423e70 100644
--- a/test/ast_mangler_test.exs
+++ b/test/blanks_test.exs
@@ -1,11 +1,11 @@
-defmodule ASTManglerTest do
+defmodule BlanksTest do
   use ExUnit.Case, async: true
 
   test "simple replacement" do
     ast = quote do: 1 + :__
 
-    mangled = ASTMangler.expand(ast, 37)
-    assert {:+, [context: ASTManglerTest, import: Kernel], [1, 37]} == mangled
+    mangled = Blanks.replace(ast, 37)
+    assert {:+, [context: BlanksTest, import: Kernel], [1, 37]} == mangled
   end
 
   test "Work with multiple different replacements" do
@@ -31,24 +31,24 @@ defmodule ASTManglerTest do
   test "complex example" do
     ast = [do: {:assert, [line: 5], [{:==, [line: 5], [true, :__]}]}]
 
-    assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, true]}]}] == ASTMangler.expand(ast, true)
+    assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, true]}]}] == Blanks.replace(ast, true)
   end
 
   test "multiple arguments" do
     ast = [do: {:assert, [line: 5], [{:==, [line: 5], [:__, :__]}]}]
 
-    assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, false]}]}] == ASTMangler.expand(ast, [true, false])
+    assert [do: {:assert, [line: 5], [{:==, [line: 5], [true, false]}]}] == Blanks.replace(ast, [true, false])
   end
 
   test "counts simple blanks" do
     ast = quote do: 1 + :__
 
-    assert ASTMangler.count(ast) == 1
+    assert Blanks.count(ast) == 1
   end
 
   test "counts multiple blanks" do
     ast = [do: {:assert, [line: 5], [{:==, [line: 5], [:__, :__]}]}]
 
-    assert ASTMangler.count(ast) == 2
+    assert Blanks.count(ast) == 2
   end
 end

From f564927751319ab36faaf87d91349322ee77eee8 Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Sun, 20 Mar 2016 19:36:57 +0000
Subject: [PATCH 5/6] Make private functions private

---
 lib/blanks.ex | 8 ++++----
 lib/koans.ex  | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/blanks.ex b/lib/blanks.ex
index 248803f..7ed8614 100644
--- a/lib/blanks.ex
+++ b/lib/blanks.ex
@@ -7,8 +7,8 @@ defmodule Blanks do
     |> elem(0)
   end
 
-  def pre(:__, [first | remainder]), do: {first, remainder}
-  def pre(node, acc), do: {node, acc}
+  defp pre(:__, [first | remainder]), do: {first, remainder}
+  defp pre(node, acc), do: {node, acc}
 
   def count(ast) do
     ast
@@ -16,6 +16,6 @@ defmodule Blanks do
     |> elem(1)
   end
 
-  def count(:__, acc), do: {node, acc+1}
-  def count(node, acc), do: {node, acc}
+  defp count(:__, acc), do: {node, acc+1}
+  defp count(node, acc), do: {node, acc}
 end
diff --git a/lib/koans.ex b/lib/koans.ex
index f54514e..e4c26c6 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -41,7 +41,7 @@ defmodule Koans do
     end
   end
 
-  def create_vars(amount) do
+  defp create_vars(amount) do
     Enum.map(0..amount, fn (idx) -> quote do: elem(converted, unquote(idx)) end)
   end
 

From 6e8845cb5145cdf6997e81f5258c5921ada9d0ff Mon Sep 17 00:00:00 2001
From: Felipe Sere <felipesere@gmail.com>
Date: Sun, 20 Mar 2016 16:23:44 +0000
Subject: [PATCH 6/6] Assert on result of Task.start_link/1

---
 lib/koans/12_task.ex        | 3 ++-
 test/koans_harness_test.exs | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/koans/12_task.ex b/lib/koans/12_task.ex
index bdfcfb1..26970ee 100644
--- a/lib/koans/12_task.ex
+++ b/lib/koans/12_task.ex
@@ -8,7 +8,8 @@ defmodule Tasks do
   end
 
   koan "if you don't need a result, use start_link/1" do
-    {:ok, _pid} = Task.start_link(fn -> 1+1 end)
+    {result, _pid} = Task.start_link(fn -> 1+1 end)
+    assert result == :__
   end
 
   koan "yield returns nothing if the task isn't done yet" do
diff --git a/test/koans_harness_test.exs b/test/koans_harness_test.exs
index 5db07bb..c86ee4d 100644
--- a/test/koans_harness_test.exs
+++ b/test/koans_harness_test.exs
@@ -222,7 +222,7 @@ defmodule KoansHarnessTest do
   test "Tasks" do
     answers = [
       10,
-      :todo,
+      :ok,
       nil,
       nil,
       9,