Comment by soygul

Quoting from the source code:

   [[ $# -gt 0 ]] && while [ "${1:0:2}" == '--' ]; do OPTION=${1:2}; [[ $OPTION =~ = ]] && declare "BOCKER_${OPTION/=*/}=${OPTION/*=/}" || declare "BOCKER_${OPTION}=x"; shift; done

If the ambition is to write lines like this, you can make it into ~1 line of code.