$ perl -MO=Concise,-exec -we's/(?<=\d)-(?=[A-Z])//ig' 1 <0> enter 2 <;> nextstate(main 1 -e:1) v 3 <$> const[PV ""] s 4 subst(/"(?<=\\d)-(?=[A-Z])"/) vK 5 <@> leave[1 ref] vKP/REFC -e syntax OK $ perl -MO=Concise,-exec -we's/(\d)-([A-Z])/$1$2/ig' 1 <0> enter 2 <;> nextstate(main 1 -e:1) v 3 subst(/"(\\d)-([A-Z])"/ replstart->4) v 4 <#> gvsv[*1] s 5 <#> gvsv[*2] s 6 <2> concat[t3] sK/2 7 <|> substcont(other->3) sK/1 8 <@> leave[1 ref] vKP/REFC -e syntax OK