From 9e16bfdac8a4202c2a9f5b0f42861db058748cfc Mon Sep 17 00:00:00 2001
From: Uku Taht <uku.taht@gmail.com>
Date: Sat, 9 Apr 2016 23:42:01 +0100
Subject: [PATCH] Attempt at making maps easier to go through

---
 lib/koans/06_maps.ex        | 50 ++++++++++++++++++-------------------
 test/koans_harness_test.exs | 12 ++++-----
 2 files changed, 30 insertions(+), 32 deletions(-)

diff --git a/lib/koans/06_maps.ex b/lib/koans/06_maps.ex
index 99b4e9c..8123bab 100644
--- a/lib/koans/06_maps.ex
+++ b/lib/koans/06_maps.ex
@@ -1,65 +1,65 @@
 defmodule Maps do
   use Koans
 
+  @person %{
+    name: "Jon",
+    last_name: "Snow",
+    age: 27
+  }
+
   koan "Maps represent structured data, like a person" do
-    assert %{ :name => "Jon",
-              :last_name => "Snow",
-              :age => 27 } == %{ :name => :__,
-                                 :last_name => "Snow",
-                                 :age => 27 }
+    assert @person == %{name: :__,
+                        last_name: "Snow",
+                        age: 27 }
   end
 
   koan "You can get all the keys from the map" do
-    assert Map.keys(%{ :name => "Jon", :last_name => "Snow", :age => 27 }) |> Enum.sort == :__
+    assert Map.keys(@person) |> Enum.sort == :__
   end
 
   koan "Or you can also get all the values from it" do
-    assert Map.values(%{ :name => "Jon", :last_name => "Snow", :age => 27 }) |> Enum.sort == :__
+    assert Map.values(@person) |> Enum.sort == :__
   end
 
   koan "Fetching a value returns a tuple with ok when it exists" do
-    assert Map.fetch(%{ :name => "Jon", :last_name => "Snow", :age => 27 }, :age) == :__
+    assert Map.fetch(@person, :age) == :__
   end
 
   koan "Or the atom :error when it doesnt" do
-    assert Map.fetch(%{ :name => "Jon", :last_name => "Snow", :age => 27 }, :family) == :__
+    assert Map.fetch(@person, :family) == :__
   end
 
   koan "Extending a map is a simple as putting in a new pair" do
-    assert Map.put(%{ :name => "Jon", :last_name => "Snow"}, :age, 27) == :__
+    person_with_hobby = Map.put(@person, :hobby, "Kayaking")
+    assert Map.fetch(person_with_hobby, :hobby) == :__
   end
 
   koan "Put can also overwrite existing values" do
-    assert Map.put(%{ :name => "Jon", :last_name => "Snow", :age => 15}, :age, 27) == :__
+    older_person = Map.put(@person, :age, 37)
+    assert Map.fetch(older_person, :age) == :__
   end
 
   koan "Or you can use some syntactic sugar for existing elements" do
-    initial = %{ :name => "Jon", :last_name => "Snow", :age => 16}
-    assert %{ initial | :age => 27 } == :__
+    younger_person = %{ @person | age: 16 }
+    assert Map.fetch(younger_person, :age) == :__
   end
 
   koan "Can remove pairs by key" do
-    assert Map.delete(%{ :name => "Jon", :last_name => "Snow", :age => 15}, :age) == :__
-  end
-
-  koan "If you have a list of pairs, you can turn them into a map" do
-    assert Map.new( [{:name, "Jon"}, {:last_name, "Snow"}, {:age, 27}] ) == :__
-  end
-
-  koan "Going back to a list of pairs is just as easy" do
-    assert Map.to_list(%{ :name => "Jon", :last_name => "Snow", :age => 27 }) == :__
+    without_age = Map.delete(@person, :age)
+    assert Map.keys(without_age) |> Enum.sort == :__
   end
 
   koan "Can merge maps" do
-    assert Map.merge(%{:name => "Jon"}, %{ :last_name => "Snow"}) == :__
+    assert Map.merge(%{name: "Jon"}, %{last_name: "Snow"}) == :__
   end
 
   koan "When merging, the last map wins" do
-    assert Map.merge(%{:name => "Robert", :last_name => "Snow"}, %{ :last_name => "Baratheon"}) == :__
+    merged = Map.merge(@person, %{ last_name: "Baratheon"})
+    assert Map.fetch(merged, :last_name) == :__
   end
 
   koan "You can also select sub-maps out of a larger map" do
-    initial = %{ :name => "Jon", :last_name => "Snow", :age => 15}
+    initial = %{ name: "Jon", last_name: "Snow", age: 15}
     assert Map.take(initial, [:name, :last_name]) == :__
   end
 end
diff --git a/test/koans_harness_test.exs b/test/koans_harness_test.exs
index b5265e0..17be4ad 100644
--- a/test/koans_harness_test.exs
+++ b/test/koans_harness_test.exs
@@ -90,14 +90,12 @@ defmodule KoansHarnessTest do
       [27, "Jon", "Snow"],
       {:ok, 27},
       :error,
-      %{ :name => "Jon", :last_name => "Snow", :age => 27 },
-      %{ :name => "Jon", :last_name => "Snow", :age => 27 },
-      %{ :name => "Jon", :last_name => "Snow", :age => 27 },
-      %{ :name => "Jon", :last_name => "Snow"},
-      %{ :name => "Jon", :last_name => "Snow", :age => 27 },
-      [age: 27, last_name: "Snow", name: "Jon" ],
+      {:ok, "Kayaking"},
+      {:ok, 37},
+      {:ok, 16},
+      [:last_name, :name],
       %{:name => "Jon", :last_name => "Snow"},
-      %{:name => "Robert", :last_name => "Baratheon"},
+      {:ok, "Baratheon"},
       %{ :name => "Jon", :last_name => "Snow"}
     ]