ubtractor : int -&gt; int list -&gt; int = &lt;fun&gt;

# [1; 2; 3] |&gt; adder 0 = (0 + 1 + 2 + 3);;
- : bool = true

# [1; 2; 3] |&gt; subtractor 10 = (10 - 1 - 2 - 3);;
- : bool = true</code></pre><p>This example provides a generic functor that works on any magma. Some concrete instances are constructed for <a href="Bastet/Int/Additive/Magma/index.html"><code>Bastet.Int.Additive.Magma</code></a> and <a href="Bastet/Int/Subtractive/Magma/index.html"><code>Bastet.Int.Subtractive.Magma</code></a>.</p><p>As 