Add intro.exs

Author: antonmi

intro.exs

@@ -0,0 +1,61 @@
+# Stateless Transformer
+plus_one = Transformer.new(:numbers, &(&1 + 1))
+plus_one = Transformer.start(plus_one)
+flow = %{numbers: [1, 2, 3, 4]}
+new_flow = Transformer.call(flow, plus_one)
+new_flow[:numbers] |> Enum.to_list()
+
+# Stateful Transformer
+sum_pairs = Transformer.new(
+  :numbers,
+  fn event, acc ->
+    case acc do
+      nil ->
+        {[], event}
+      number ->
+        {[number + event], nil}
+    end
+  end
+) |> Transformer.start()
+
+new_flow = flow |> Transformer.call(plus_one) |> Transformer.call(sum_pairs)
+new_flow[:numbers] |> Enum.to_list()
+
+# Mixer
+flow = %{num1: [1, 2, 3], num2: [4, 5, 6]}
+mixer = Mixer.new([:num1, :num2], :numbers) |> Mixer.start()
+new_flow = flow |> Mixer.call(mixer) |> Transformer.call(plus_one)
+new_flow[:numbers] |> Enum.to_list()
+
+# Composite
+plus_one = Transformer.new(:numbers, &(&1 + 1))
+mixer = Mixer.new([:num1, :num2], :numbers)
+composite = Composite.new([mixer, plus_one]) |> Composite.start()
+flow = %{num1: [1, 2, 3], num2: [4, 5, 6]}
+new_flow = flow |> Composite.call(composite)
+new_flow[:numbers] |> Enum.to_list()
+
+# Complex composite
+plus_one = Transformer.new(:numbers, &(&1 + 1))
+mixer = Mixer.new([:num1, :num2], :numbers)
+composite1 = Composite.new([mixer, plus_one])
+
+sum_pairs = Transformer.new(
+  :numbers,
+  fn event, acc ->
+    case acc do
+      nil ->
+        {[], event}
+      number ->
+        {[number + event], nil}
+    end
+  end
+)
+
+composite2 = Composite.new([sum_pairs])
+
+composite = Composite.new([composite1, composite2]) |> Composite.start()
+
+flow = %{num1: [1, 2, 3], num2: [4, 5, 6]}
+new_flow = flow |> Composite.call(composite)
+new_flow[:numbers] |> Enum.to_list()