E.g:

MP_PPD = function(x, Data, reps=1, nyrs, outfile= NA){

lastyr = match(Data@LHYear, Data@Year)
pyr = length(Data@Year) - lastyr

if(pyr > nyrs){

 if(is.na(outfile)) outfile= paste0(getwd(), "/PPD.rda")
 saveRDS(Data, outfile)
 print(paste0("PPD written to ", outfile))
 stop()

} # end of save PPD

FMSYref(x, Data, reps) # default advice

}

class(MP_PPD) = 'MP'

where the user can just adjust outfile and nyrs as they like

formals(MP_PPD)$nyrs = 10
formals(MP_PPD)$outfile = "C:/temp/MSEstuff/myPPD.rda"