;&gt;</span> <span class="type-var">'final</span>)</span> <span>&#45;&gt;</span> <span><span>(<span class="type-var">'a</span> <span>&#45;&gt;</span> <span class="type-var">'final</span>, <span><span class="type-var">'e</span> <a href="index.html#type-errors">errors</a></span>)</span> Stdlib.result</span></code></dt><dd><p>Start the build pipeline for a validator</p><pre><code class="ml">let validator input =
  let open Validator in
  build build_valid
  |&gt; validate input.age (int_min 13 &quot;Must be 1