#outer tryCatch, see 1.
tryCatch({
  #user code block
  #2a. user specific tryCatch, object "vec" not defined
  tryCatch(print(vec),error=function(e) {print("Non-fatal error. Script execution continued.");print(e);})

  #2b. user specific tryCatch
  tryCatch(vec*2)

  #2c. user specific tryCatch
  tryCatch(vec*parameter1, error=function(e) {print("Additional fatal error information. Script execution aborted.");stop(e);})
  #end of user code block
},
     #outer tryCatch error handler in order to handle fatal errors
     error=function(e) {print("Fatal error");print(e);}
    )

ourError <-
    function(original, message, class="ourError")
{
    msg <- paste(message, conditionMessage(original), sep="n  ")
    structure(list(message = msg, call = conditionCall(original)),
              class = c(class, class(original)))
}

tryCatch(vec*parameter1, error=function(e) {
    err <- ourError(e, "addition fatal info; script aborted")
    stop(err)
})

tryCatch({
    tryCatch(stop("oops"), error=function(e) {
        err <- ourError(e, "addition fatal info; script aborted",
                      c("fatal", "ourError"))
        stop(err)
    })
}, ourError=function(err) {
    message("We caught but didn't handle this:n", err)
}, error =function(err) {
    message("This one got away: ", err)
})