@hackage gulcii0.2.0.3

GULCII is an untyped lambda calculus interpreter supporting interactive modification of a running program with graphical display of graph reduction.

There are three variants of lambda abstraction: lazy, strict, and copy:

> x . f x x -- x is evaluated lazily with sharing > x ! f x x -- x is evaluated strictly and shared > x ? f x x -- x is copied before any evaluation

There is additional syntax sugar for natural numbers and lists, using http://en.wikipedia.org/wiki/Mogensen%E2%80%93Scott_encoding#Scott_encoding:

> [0,1,2,3]

There is a small standard library based loosely around the Haskell Prelude, with additions geared towards MIDI generation for live-coding music, implemented using a mechanism similar to Debug.Trace.trace:

> x y . { print : x } y

Quick start:

gulcii
:load mars
main
:quit

If you have Pure-data and Timidity, try:

timidity -iA -Oj &
pd -alsamidi ~/.cabal/share/gulcii-0.2.0.3/extra/fudi2midi.pd &
gulcii | pdsend 8765

See also: live-sequencer which has many more features (but no sharing during evaluation).