title: String concatenation in solidity?
body: <p>How do I concatenate strings in solidity?</p>
  <pre><code>var str = 'asdf'
  var b = str + 'sdf'
  </code></pre>
  <p>seems not to work.</p>
  <p>I looked up <a href="https://github.com/ethereum/wiki/wiki/Solidity-Tutorial#elementary-types-value-types" rel="nofollow noreferrer">the documentation</a> and there is not much mentioned about string concatenation.</p>
  <p>But it is stated that it works with the dot ('.')?</p>
  <pre><code>&quot;[...] a mapping key k is located at sha3(k . p) where . is concatenation.&quot;
  </code></pre>
  <p>Didn't work out for me too. :/</p>