title: TradingView's ‘undeclared identifier’ error in pine editor
body: <p>Have a problem with custom identifier in pine on tradingview:</p>
  
  <pre><code>smma(src, length) =&gt;
     smma = na(smma[1]) ? sma(src, length) : (smma[1] * (length - 1) + src) / length
     smma
  </code></pre>
  
  <p>Got error in line 2: Undeclared identifier<code>smma</code> Anybody know how to fix it ? Will be appreciate for any suggestions </p>