e">(a+b)</span></code>.  Each <code class="docutils literal notranslate"><span class="pre">\\</span></code> is parsed in a quoted argument
as just <code class="docutils literal notranslate"><span class="pre">\</span></code>, so the regex itself is actually <code class="docutils literal notranslate"><span class="pre">\(\a\+\b\)</span></code>.  This
can alternatively be specified in a <a class="reference internal" href="../manual/cmake-language.7.html#bracket-argument"><span class="std std-ref">Bracket Argume