 result to stdout. Use only if the output format is stable and useful enough that it may conceivably get piped to another program, ie, almost never (use <code>progress</code> instead otherwise).</p></div></div><div class="odoc-spec"><div class="spec value" id="val-user_error" class="anchored"><a href="#val-user_error" class="anchor"></a><code><span><span class="keyword">val</span> user_error : <span><span><span>( <span class="type-var">'a</span>, <span class="xref-unresolved">F</span>.formatter, unit )</spa