#type-validator_builder">validator_builder</a></span></code></dt><dd><p>Validate if a string parses to an Int. Returns the Int if so</p><pre><code class="ml">let validator input =
  let open Validator in
  build build_valid
  |&gt; validate input.age (string_is_int &quot;Must be a number&quot;)</code></pre></dd></dl><dl><dt class="spec value" id="val-string_has_min_length"><a href="#val-string_has_min_length" class="anchor"></a><code><span class="keyword">val</span> string_has_min_length : int <span>&#45;&g