From da5d2d85155eb46930b0f5ea1c28439469af72ce Mon Sep 17 00:00:00 2001
From: Greg Burri <greg.burri@gmail.com>
Date: Sat, 25 Apr 2020 16:13:53 +0200
Subject: [PATCH] Add some code samples.

---
 sandbox.exs | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 76 insertions(+), 1 deletion(-)

diff --git a/sandbox.exs b/sandbox.exs
index 58ff0da..baa66cd 100644
--- a/sandbox.exs
+++ b/sandbox.exs
@@ -18,6 +18,7 @@ IO.inspect b, label: "b"
 {x, x} = {10, 10} # 'x' must be bind to the same value.
 IO.inspect x, label: "x"
 
+IO.puts "=== Binary ==="
 str = "hëllö" <> <<0>> # Append a zero to the string (binary).
 IO.inspect str, binaries: :as_binaries
 
@@ -31,15 +32,18 @@ IO.inspect(is_bitstring <<0xFF, 0xF::4>>) # true.
 IO.inspect(x === ?ü) # true.
 
 # 'charlist': the string in Erlang.
+IO.puts "=== charlist ==="
 IO.inspect('hëllò', charlists: :as_lists)
 IO.inspect(to_string('hëllò') == "hëllò") # true.
 IO.inspect('hëllò' == to_charlist("hëllò")) # true.
 
 # keyword list.
+IO.puts "=== keyword list ==="
 IO.inspect([{:a, 1}, {:b, 2}] === [a: 1, b: 2]) # true.
 IO.inspect(a: 1, b: 2, c: 3) # Brackets omitted.
 
 # Maps.
+IO.puts "=== Map ==="
 map = %{:a => 1, 2 => :b}
 IO.inspect map[:a] # Print 1.
 IO.inspect map.a # Special syntax with atom key, print 1.
@@ -50,10 +54,81 @@ IO.inspect a # Print 1.
 IO.inspect %{map | 2 => "two"} # Updating 'map'.
 
 # Module.
+IO.puts "=== Module ==="
 defmodule Math do
     def sum(a, b) do
         a + b
     end
+
+    def zero?(0), do: true
+    def zero?(x) when is_integer(x), do: false
+end
+
+IO.inspect Math.sum(1, 2)
+IO.inspect Math.zero?(1)
+
+fun = &Math.zero?/1 # '&' to capture a function as a lambda (and use with high level functions).
+IO.inspect fun.(0) # Calling it with same syntaxe as lambdas.
+
+fun2 = &(&1 + 1) # Shortcut syntax: '&1' is the first parameter.
+fun3 = &"Good #{&1}"
+IO.inspect fun2.(3) # Print 4.
+
+# Enum.
+IO.puts "=== Enum ==="
+IO.inspect Enum.map([1, 2, 3], &(2 * &1))
+IO.inspect Enum.map(%{1 => 2, 3 => 4}, fn {k, v} -> k * v end)
+IO.inspect Enum.map(1..10, &(3 * &1))
+IO.inspect Enum.reduce(1..3, 0, &+/2) # 1 + 2 + 3.
+
+odd? = &(rem(&1, 2) != 0)
+IO.inspect 1..100_000 |> Enum.map(&(3 * &1)) |> Enum.filter(odd?) |> Enum.sum
+
+# Process.
+IO.puts "=== Process ==="
+pid =
+    spawn fn ->
+        receive do
+            {:hello, sender, msg} ->
+                IO.puts "Message received: '#{msg}'"
+                send sender, :ok
+        end
+    end
+
+
+send pid, {:hello, self(), "Salut"}
+receive do
+    :ok -> IO.puts "Message delivered!"
+after
+    1_000 -> IO.puts "Message not delivered :("
+end
+
+IO.puts "=== State ==="
+defmodule KV do # Key-Value.
+    def stark_link do
+        Task.start_link(fn -> loop %{} end)
+    end
+
+    defp loop(map) do
+        receive do
+            {:get, key, caller} ->
+                send caller, Map.get(map, key)
+                loop map
+            {:put, key, value} ->
+                loop Map.put(map, key, value)
+        end
+    end
+end
+
+{:ok, kv} = KV.stark_link
+send kv, {:put, :a, 42}
+send kv, {:put, :b, 420}
+send kv, {:get, :b, self()}
+receive do
+    value -> IO.puts "Value received: #{value}"
 end
 
-IO.inspect Math.sum(1, 2)
\ No newline at end of file
+IO.puts "=== Agent ==="
+{:ok, pid} = Agent.start_link(fn -> %{} end)
+Agent.update(pid, fn map -> Map.put(map, :hello, :world) end)
+IO.inspect Agent.get(pid, fn map -> Map.get(map, :hello) end)
\ No newline at end of file
-- 
2.43.0