# `constant` `constant` returns the constant value for a given string: <table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre>1 2</pre></div></td><td class="code"><div class="highlight"><pre>{{ some_date|date(constant('DATE_W3C')) }} {{ constant('Namespace\\Classname::CONSTANT_NAME') }} </pre></div></td></tr></table> As of 1.12.1 you can read constants from object instances as well: <table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre>1</pre></div></td><td class="code"><div class="highlight"><pre>{{ constant('RSS', date) }} </pre></div></td></tr></table>