11 Teaching Languages
The teaching language are implemented via the tools interface and thus not part of DrRacket proper, but one helper library is documented here.
These strings are used as the prefix in a file saved while using the teaching languages. Each string is on a separate line in the saved file.
(htdp-file-prefix? ip) → boolean?
ip : input-port?
Determines if the contents of ip is one of the possible prefixes that DrRacket saves at the beginning of a teaching language file.
In the case that this function returns #t, it consumes the entire prefix from ip (and discards it). In the case that this function returns #f, it does not consume anything from ip.