Regular expression not support

Hi Team,

The reg provided by the tech team %\d+$s|${{(\w+)}}|${\w+} to match
%2$s
${1}
${2}
${airportName}
${cityNameName}
${{1}}
${{2}}
${{3}}
Which was not working for Xbench checklist, the error says “Incomplete expression”
What’s the correct expression is to support Xbench checklist?

Thanks
Aaron