title: Regular Expressions in OCaml
body: <p>I want to use <em>regexps</em> in OCaml and it seems that <code>Str</code> module provides these functionalities.</p>
  
  <p>So I tried with a simple program:</p>
  
  <pre><code>open Str
  let regx = regexp "."
  </code></pre>
  
  <p>but it gives me the following error</p>
  
  <blockquote>
    <p>File "lol.ml", line 1, characters 0-1:
    Error: Error while linking lol.cmo:
    Reference to undefined global `Str'</p>
  </blockquote>
  
  <p>As if module is not present but if I remove <code>open Str</code> it says that <code>regexp</code> is an unbound value.</p>
  
  <p>I don't get what kind of issue it is, <code>Str</code> should be a standard module (according to <a href="http://caml.inria.fr/pub/docs/old-311/libref/Str.html" rel="noreferrer">http://caml.inria.fr/pub/docs/old-311/libref/Str.html</a>) so I'm clueless.. the only think I thought is that signature (<code>mli</code>) is present but implementation (<code>ml</code>) is not.</p>
  
  <p>I'm running <code>Objective Caml version 3.11.0</code> according to <code>ocaml</code> tool.</p>
  
  <p>Can anyone help me figuring this out?
  Thanks in advance</p>