> scheme48
Welcome to Scheme 48 1.8 (made by root on Wed Sep 24 22:37:08 UTC 2008)
Copyright (c) 1993-2008 by Richard Kelsey and Jonathan Rees.
Please report bugs to scheme-48-bugs@s48.org.
Get more information at http://www.s48.org/.
Type ,? (comma question-mark) for help.
> (define (f string-1 string-2 separator)
    (string-append string-1 separator separator string-2))
; no values returned
> (f "Rosetta" "Code" ":")
"Rosetta::Code"
> ^D
Exit Scheme 48 (y/n)? ^D
I'll only ask another 100 times.
Exit Scheme 48 (y/n)? ^D
I'll only ask another 99 times.
Exit Scheme 48 (y/n)? y
>