Update markov chains to be backed by maps instead of lists

This should hopefully speed up lookups and stuff like that.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

test/contrib/markov/chain_test.exs

@@ -5,66 +5,66 @@ defmodule MarkovChainTest do
   test "chain train works correctly" do
     chain = %Chain {order: 2}
             |> Chain.train(~w(foo bar baz))
-    assert chain.chain == [
-      {["bar", "baz"], %{nil => 1}},
-      {["foo", "bar"], %{"baz" => 1}},
-    ]
+    assert chain.chain == %{
+      ["bar", "baz"] => %{nil => 1},
+      ["foo", "bar"] => %{"baz" => 1},
+    }
 
     chain = chain |> Chain.train(~w(foo bar baz))
 
-    assert chain.chain == [
-      {["bar", "baz"], %{nil => 2}},
-      {["foo", "bar"], %{"baz" => 2}},
-    ]
+    assert chain.chain == %{
+      ["bar", "baz"] => %{nil => 2},
+      ["foo", "bar"] => %{"baz" => 2},
+    }
 
     chain = chain |> Chain.train(~w(baz bar foo))
 
-    assert chain.chain == [
-      {["bar", "foo"], %{nil => 1}},
-      {["baz", "bar"], %{"foo" => 1}},
-      {["bar", "baz"], %{nil => 2}},
-      {["foo", "bar"], %{"baz" => 2}},
-    ]
+    assert chain.chain == %{
+      ["bar", "foo"] => %{nil => 1},
+      ["baz", "bar"] => %{"foo" => 1},
+      ["bar", "baz"] => %{nil => 2},
+      ["foo", "bar"] => %{"baz" => 2},
+    }
 
     chain = chain |> Chain.train(~w(a b c))
-    assert chain.chain == [
-      {["b", "c"], %{nil => 1}},
-      {["a", "b"], %{"c" => 1}},
-      {["bar", "foo"], %{nil => 1}},
-      {["baz", "bar"], %{"foo" => 1}},
-      {["bar", "baz"], %{nil => 2}},
-      {["foo", "bar"], %{"baz" => 2}},
-    ]
+    assert chain.chain == %{
+      ["b", "c"] => %{nil => 1},
+      ["a", "b"] => %{"c" => 1},
+      ["bar", "foo"] => %{nil => 1},
+      ["baz", "bar"] => %{"foo" => 1},
+      ["bar", "baz"] => %{nil => 2},
+      ["foo", "bar"] => %{"baz" => 2},
+    }
   end
 
   test "chain add_weight works correctly" do
     chain = %Chain {order: 2}
             |> Chain.add_weight(["foo", "bar"], "baz")
-    assert chain.chain == [
-      {["foo", "bar"], %{"baz" => 1}}
-    ]
+    assert chain.chain == %{
+      ["foo", "bar"] => %{"baz" => 1},
+    }
 
     chain = chain |> Chain.add_weight(["foo", "bar"], "baz", 2)
 
-    assert chain.chain == [
-      {["foo", "bar"], %{"baz" => 3}}
-    ]
+    assert chain.chain == %{
+      ["foo", "bar"] => %{"baz" => 3},
+    }
 
     chain = chain |> Chain.add_weight(["foo", "bar"], "qux")
-    assert chain.chain == [
-      {["foo", "bar"], %{"baz" => 3, "qux" => 1}}
-    ]
+    assert chain.chain == %{
+      ["foo", "bar"] => %{"baz" => 3, "qux" => 1},
+    }
 
     chain = chain |> Chain.add_weight(["bar", "baz"], "qux")
-    assert chain.chain == [
-      {["bar", "baz"], %{"qux" => 1}},
-      {["foo", "bar"], %{"baz" => 3, "qux" => 1}},
-    ]
+    assert chain.chain == %{
+      ["bar", "baz"] => %{"qux" => 1},
+      ["foo", "bar"] => %{"baz" => 3, "qux" => 1},
+    }
 
     chain = chain |> Chain.add_weight(["bar", "baz"], nil)
-    assert chain.chain == [
-      {["bar", "baz"], %{"qux" => 1, nil => 1}},
-      {["foo", "bar"], %{"baz" => 3, "qux" => 1}},
-    ]
+    assert chain.chain == %{
+      ["bar", "baz"] => %{"qux" => 1, nil => 1},
+      ["foo", "bar"] => %{"baz" => 3, "qux" => 1},
+    }
   end
 end