[Pharo-users] PetitParser problem with plus

There is something about plus that I don’t understand. In the following code if I parse for (x , x) then I get what I expect. If I parse for (x plus) then the image hangs. What am I doing wrong? James | a notA x y | a := $a asParser. notA := $a asParser negate star flatten. x := a / notA. y := x , x. “works fine” y := x plus. “never finishes” ^y end parse: 'ab’.