The new Knights of the Lambda Calculus are posed for a major crusade on the bastions of imperative programming, in particular the Object Barbarians whose side effects, cavalier approach to types have dominated the commercial software landscape for almost three decades. The Objects used a GUI Trojan horse and massive propaganda on Reuse and Software Process to infiltrate and capture enterprise castles and enslave application developers.
The Knights are lead by seasoned experts and accompanied by younger fighters armed with new weapons based on decades of research. Jousting at CUFP, GOTO/YOW and Lambda Jam gatherings has strengthened the Knights and increased diversity from the clans of Lisp, Scheme, Racket, Closure; ML, Haskell, OCaml, Scala, LINQ; Actors/Erlang/Rx and APL/J/k and converts subverting popular OO languages with FP features.
This talk is addressed to our 21st knights and their followers in preparation for the challenges ahead. We share technical and commercial successes and failures from past language crusades in the hopes and expectation that FP will indeed finally achieve its due place in the practice of commercial software development. Success in the large requires more than might, strategy and tactics. Sustainability requires diplomacy; accommodation of less empowered and acknowledging that side effects will linger for the rest of time.