func main { mega | with args ;
    "Welcome to the SPL REPL!" println
    "Enter any code after the cursor to execute it.\n" println

    "REPL" =program-name
    while { 1 } {
        catch {
            "  > " print readln dyn-read exec2 "\n" print
        } 
        with { with err ;
            err:message dup null eq if {
                pop
                "Uncaught error."
            } err:trace

            with msg trace ;
            program-name dup if {
                program-name print " panicked at:" println
            } not if {
                "Program panicked at:" println
            }
            &println trace:foreach 
            "\nPanic message:" println
            "    " print msg println
            "\nRecovering." println
        }
    }
}