- The unit test framework for the teaching languages provides check-member-of and check-range for checking "random functions", i.e., "functions" that may produce several different results for one and the same argument.
- Added a new image library, 2htdp/image. Significant changes from htdp/image:
- copying and pasting does not introduce jaggies
- equal? comparisons are more efficient
- added rotation & scaling
- got rid of pinholes (new overlay, beside, above functions based on bounding boxes)
- The scheme/vector library provides common vector operations (also reprovided by scheme).
- The scheme/promise library provides several new kinds of promises with alternatives execution strategies.
- New port-reading utilities: in-port, port->list, file->list.
- A new require-macro, path-up, for requiring a file that is higher in the directory tree.
Posted by Eli Barzilay at 06:03
PLT Scheme version 4.2.3 is now available from