PLT Scheme v4.2.3

[Eli Barzilay]

PLT Scheme version 4.2.3 is now available from

http://plt-scheme.org/

* 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.

[Note that mirror sites can take a while to catch up with the new
downloads.]

[Apologies if this appears twice, the news gateway I used seems
unresponsive.]

Feedback Welcome,
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!

[Eli Barzilay]

PLT Scheme version 4.2.3 is now available from

http://plt-scheme.org/

* 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.

[Note that mirror sites can take a while to catch up with the new
downloads.]

Feedback Welcome,