[plt-scheme] On PLaneT packages and compatible upgrades

Richard Cobbe writes:
 > However, it does proceed from the assumption that adding functionality
 > should be a compatible upgrade.  I'm wondering if we should continue to
 > hold to that assumption.

Again, invoking Java as precedent:

http://java.sun.com/docs/books/jls/third_edition/html/binaryComp.html

The language specification spells out in great detail which changes to
a package, class, or interface preserve "binary compatibility" and which
do not.  In particular, adding a new class and adding a new method to
an existing class do not.

--dougorleans at gmail.com