The FinnAPL Idiom list is absolutely invaluable as an exposition of how APL can be used to implement new abstractions. A little blue book published by the Finni

The FinnAPL Idiom list is absolutely invaluable as an exposition of how APL can be used to implement new abstractions. A little blue book published by the Finnish APL Association, it contains about 600 hand polished APL idioms. http://www.finnapl.fi/idilib.htm http://www.finnapl.fi/idilib.htm APL is heady stuff for the right kind of mind. I remember Larry Breed demonstrating how the APL language notation often automatically extends two dimensional processing to three or more dimensions.