Posted by Sean P. DeNigris on Nov 12, 2010; 4:56am
URL: https://forum.world.st/PetitParser-problem-flattening-a-collection-tp3038980p3039052.html

Lukas Renggli wrote

      driveType separatedBy: ', ' asParse

(and see the implementation of #separatedBy: if this is not exactly
what you are looking for)

Thanks Lukas.  I ended up with:
        driveTypeList := (driveType, additionalDriveType star) ==> [ :nodes |
                (Array with: nodes first), nodes second ].