Pattern match handle empty array error

README.md

@@ -21,5 +21,20 @@ git clone https://github.com/MichaelDimmitt/transcript-fromElixirWorkshop.git;
 cd transcript-fromElixirWorkshop;
 iex -S mix;
 ```
+#Usage Below
 
+## bash
+`iex -S mix`
+
+## iex syntax:
+```elixir
+stack = Conversation.new
+Conversation.pop(stack)
+Conversation.pop(stack)
+Conversation.pop(stack)
+Conversation.pop(stack)
+Conversation.pop(stack)
+
+Conversation.iCanDoStuffAllTheStuffButYouNoSee
+```
 

lib/conversation.ex

@@ -4,15 +4,61 @@ defmodule Conversation do
   """
 
   @doc """
-  Hello world.
+  Do the stuff but dont tell me.
 
   ## Examples
+      iex> Conversation.iCanDoStuffAllTheStuffButYouNoSee
+      :ok
 
-      iex> Conversation.hello
-      :world
+  Tell me the stuff you are doing.
 
+  ## Examples
+      iex> stack = Conversation.new
+      iex> Conversation.pop(stack)
+      iex> Conversation.pop(stack)
+      iex> Conversation.pop(stack)
+      iex> Conversation.pop(stack)
+      iex> Conversation.pop(stack)
+      :ok
   """
-  def hello do
-    :world
+
+  def iCanDoStuffAllTheStuffButYouNoSee do
+    stack = Conversation.new
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+    Conversation.pop(stack)
+  end
+
+  def new do
+    person1 = Conversation.audience_member
+    Conversation.transcript(person1)
+    Conversation.transcript(person1)
+    Conversation.transcript(person1)
+    person1
+  end
+
+  def audience_member do
+    Stack.new
+  end
+
+  def show(pid) do
+    Stack.show(pid)
+  end
+
+  def peek(pid) do
+    Stack.peek(pid)
+  end
+
+  def transcript (stack) do
+    Stack.push(stack, :foo)
+    Stack.push(stack, :bar)
+  end
+
+  def pop(stack) do
+    Stack.pop(stack)
   end
 end

lib/stack.ex

@@ -3,30 +3,71 @@ defmodule Stack do
     spawn(fn -> loop([]) end)
   end
 
+  def peek(pid) do
+    send(pid, {:peek, self()})
+    receive do
+      {:peek, val} -> val
+    after
+       0 -> :ok
+    end
+  end
+
+  def show(pid) do
+    send(pid, {:show, self()})
+    receive do
+      {:pop, val} -> val
+    after
+       0 -> :ok
+    end
+  end
+
   def push(pid, val) do
     send(pid, {:push, val})
   end
 
   def pop(pid) do
     send(pid, {:pop, self()})
-    val = send(pid, {:pop, self()})
-
     receive do
-      {:pop, val} -> val
+      val ->
+        IO.puts "Resulting variable:  #{ inspect val } ."
+        val
+    after
+      0 -> :ok
     end
-
   end
 
   def loop(state) do
     new_state =
       receive do
-        {:push, val} -> [val | state]
+
+        {:peek, caller} ->
+          [head | _] = state
+          send(caller, {:peek, head})
+          state
+
+        {:show, caller} ->
+          send(caller, {:pop, state})
+          state
+
+        {:push, val} ->
+          [val | state]
 
         {:pop, caller} ->
-          [head | new_state] = state
-        send(caller, {:pop, head})
-        new_state
+          check(state, caller)
+
       end
     loop(new_state)
   end
+
+  def check([], caller) do
+    send(caller, [])
+    []
+  end
+
+  def check(state, caller) do
+    IO.puts "current state:  #{ inspect state }"
+    [head | new_state] = state
+    send(caller, head)
+    new_state
+  end
 end