title: Error when embedding regular expression (phone numb validate) on xml schema (xsd)
body: <p>I don't understand why this regular expression for validation international phone number gives an error when embedded on xml-schema:</p>
  
  <pre><code>&lt;xs:simpleType name="phoneType"&gt;
    &lt;xs:restriction base="xs:string"&gt;
        &lt;xs:pattern value="^\+(?:[0-9] ?){6,14}[0-9]$" /&gt;
    &lt;/xs:restriction&gt;
  &lt;/xs:simpleType&gt;
  </code></pre>
  
  <p>What's wrong with it? Does support group matching? Why is not supported by <a href="http://www.w3.org/2001/XMLSchema" rel="nofollow noreferrer">Xml Schema</a> ?</p>
  
  <p>Thank you very much.</p>
  
  <p>Indrit</p>