Merge pull request #92 from iamvery/update-koans

Update various koans

lib/koans/07_pattern_matching.ex

@@ -5,13 +5,18 @@ defmodule PatternMatching do
     assert match?(1, ___)
   end
 
-  koan "A pattern can change" do
+  koan "A value can be bound to a variable" do
+    a = 1
+    assert a == ___
+  end
+
+  koan "A variable can be rebound" do
     a = 1
     a = 2
     assert a == ___
   end
 
-  koan "A pattern can also be strict" do
+  koan "A variable can be pinned to be prevent it from being rebound" do
     a = 1
     assert_raise MatchError, fn() ->
       ^a = ___
@@ -44,12 +49,18 @@ defmodule PatternMatching do
     assert items == ___
   end
 
-  koan "Patterns show what you really care about" do
+  koan "Maps support partial pattern matching" do
     %{make: make} = %{type: "car", year: 2016, make: "Honda", color: "black"}
 
     assert make == ___
   end
 
+  koan "Lists must match exactly" do
+    assert_raise ___, fn ->
+      [a, b] = [1,2,3]
+    end
+  end
+
   koan "The pattern can make assertions about what it expects" do
     assert match?([1, _second, _third], ___)
   end
@@ -58,7 +69,7 @@ defmodule PatternMatching do
   def make_noise(%{type: "dog"}), do: "Woof"
   def make_noise(_anything), do: "Eh?"
 
-  koan "Functions can declare what kind of arguments they accept" do
+  koan "Functions perform pattern matching on their arguments" do
     cat = %{type: "cat"}
     dog = %{type: "dog"}
     snake = %{type: "snake"}
@@ -99,4 +110,9 @@ defmodule PatternMatching do
     %Animal{name: name} = %Animal{kind: "dog", name: "Max"}
     assert name == ___
   end
+
+  koan "Structs will even match with a regular map" do
+    %{name: name} = %Animal{kind: "dog", name: "Max"}
+    assert name == ___
+  end
 end

lib/koans/08_functions.ex

@@ -26,7 +26,7 @@ defmodule Functions do
     String.duplicate(message, times)
   end
 
-  koan "Not all arguments are always needed" do
+  koan "Functions can have default argument values" do
     assert repeat_again("Hello ") == ___
     assert repeat_again("Hello ", 2) == ___
   end
@@ -50,7 +50,7 @@ defmodule Functions do
   def the_length(0), do: "It was zero"
   def the_length(number), do: "The length was #{number}"
 
-  koan "For those individual one-offs, you can even guard on the arguments themselves" do
+  koan "For simpler cases, pattern matching is effective" do
     assert the_length(0) == ___
     assert the_length(5) == ___
   end
@@ -72,6 +72,11 @@ defmodule Functions do
     assert times_five_and_then(2, &square/1) == ___
   end
 
+  koan "The '&' operation is not needed for anonymous functions" do
+    cube = fn number -> number * number * number end
+    assert times_five_and_then(2, cube) == ___
+  end
+
   koan "Functions can be combined elegantly with the pipe operator" do
     result = "full-name"
     |> String.split("-")

lib/koans/10_processes.ex

@@ -2,11 +2,11 @@ defmodule Processes do
   use Koans
 
   koan "You are a process" do
-    assert Process.alive?(self()) == ___
+    assert Process.alive?(self) == ___
   end
 
   koan "You can ask a process to introduce itself" do
-    information = Process.info(self())
+    information = Process.info(self)
 
     assert information[:status] == ___
   end
@@ -18,7 +18,7 @@ defmodule Processes do
   end
 
   koan "You can send messages to processes" do
-    send self(), "hola!"
+    send self, "hola!"
 
     receive do
       msg -> assert msg == ___
@@ -31,12 +31,12 @@ defmodule Processes do
                       end
                  end)
 
-    send pid, {:hello, self()}
+    send pid, {:hello, self}
     assert_receive ___
   end
 
   koan "Waiting for a message can get boring" do
-    parent = self()
+    parent = self
     spawn(fn -> receive do
                 after
                   5 -> send parent, {:waited_too_long, "I am impatient"}
@@ -47,7 +47,7 @@ defmodule Processes do
   end
 
   koan "Killing a process will terminate it" do
-    pid = spawn(fn -> Process.exit(self(), :kill) end)
+    pid = spawn(fn -> Process.exit(self, :kill) end)
     :timer.sleep(500)
     assert Process.alive?(pid) == ___
   end
@@ -61,7 +61,7 @@ defmodule Processes do
   end
 
   koan "Trapping will allow you to react to someone terminating the process" do
-    parent = self()
+    parent = self
     pid = spawn(fn ->
                       Process.flag(:trap_exit, true)
                       send parent, :ready
@@ -101,7 +101,7 @@ defmodule Processes do
   end
 
   koan "If you monitor your children, you'll be automatically informed for their depature" do
-    spawn_monitor(fn -> Process.exit(self(), :normal) end)
+    spawn_monitor(fn -> Process.exit(self, :normal) end)
 
     assert_receive {:DOWN, _ref, :process, _pid, ___}
   end

test/koans/functions_koans_test.exs

@@ -14,6 +14,7 @@ defmodule FunctionsTests do
       6,
       6,
       100,
+      1000,
       "Full Name",
     ]
 

test/koans/patterns_koans_test.exs

@@ -4,6 +4,7 @@ defmodule PatternsTests do
 
   test "Pattern Matching" do
     answers = [
+      1,
       1,
       2,
       2,
@@ -12,11 +13,13 @@ defmodule PatternsTests do
       3,
       "eggs, milk",
       "Honda",
+      MatchError,
       [1,2,3],
       {:multiple, ["Meow", "Woof", "Eh?"]},
       {:multiple, ["Mickey", "Donald", "I need a name!"]},
       "dog",
       "Max",
+      "Max",
     ]
 
     test_all(PatternMatching, answers)