- <h3><a href="../index.html">Table Of Contents</a></h3>
- <ul>
-<li><a class="reference internal" href="#">Type Checking</a><ul>
-<li><a class="reference internal" href="#an-example">An Example</a></li>
-<li><a class="reference internal" href="#unification-works-in-reverse">Unification Works “in Reverse”</a></li>
-<li><a class="reference internal" href="#failing-a-check">Failing a Check</a></li>
+<h1 class="logo"><a href="../index.html">Thun</a></h1>
+
+
+
+
+
+
+
+
+<h3>Navigation</h3>
+<ul class="current">
+<li class="toctree-l1"><a class="reference internal" href="Intro.html">Thun: Joy in Python</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../joy.html">Joy Interpreter</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../stack.html">Stack or Quote or Sequence or List…</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../parser.html">Parsing Text into Joy Expressions</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../pretty.html">Tracing Joy Execution</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../library.html">Function Reference</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../lib.html">Functions Grouped by, er, Function with Examples</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../types.html">Type Inference of Joy Expressions</a></li>
+<li class="toctree-l1 current"><a class="reference internal" href="index.html">Essays about Programming in Joy</a><ul class="current">
+<li class="toctree-l2"><a class="reference internal" href="Developing.html">Developing a Program in Joy</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Quadratic.html">Quadratic formula</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Replacing.html">Replacing Functions in the Dictionary</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Recursion_Combinators.html">Recursion Combinators</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Ordered_Binary_Trees.html">Treating Trees I: Ordered Binary Trees</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Treestep.html">Treating Trees II: <code class="docutils literal notranslate"><span class="pre">treestep</span></code></a></li>
+<li class="toctree-l2"><a class="reference internal" href="Generator_Programs.html">Using <code class="docutils literal notranslate"><span class="pre">x</span></code> to Generate Values</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Newton-Raphson.html">Newton’s method</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Square_Spiral.html">Square Spiral Example Joy Code</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Zipper.html">Traversing Datastructures with Zippers</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Types.html">The Blissful Elegance of Typing Joy</a></li>
+<li class="toctree-l2 current"><a class="current reference internal" href="#">Type Checking</a></li>
+<li class="toctree-l2"><a class="reference internal" href="NoUpdates.html">No Updates</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Categorical.html">Categorical Programming</a></li>
+<li class="toctree-l2"><a class="reference internal" href="The_Four_Operations.html">The Four Fundamental Operations of Definite Action</a></li>
+<li class="toctree-l2"><a class="reference internal" href="Derivatives_of_Regular_Expressions.html">∂RE</a></li>