data-treify

This package is a (probably temporary) fork of Andy gill's data-reify package. I've tweaked it for typed syntax representations for use with GADTs. data-reify provided the ability to turn recursive structures into explicit graphs. Many (implicitly or explicitly) recursive data structure can be given this ability, via a type class instance. This gives an alternative to using Ref for observable sharing. Observable sharing in general is unsafe, so we use the IO monad to bound this effect, but can be used safely even with unsafePerformIO if some simple conditions are met. Typically this package will be used to tie the knot with DSL's that depend of observable sharing, like Lava. Providing an instance for MuRef is the mechanism for allowing a structure to be reified into a graph, and several examples of this are provided. Version 0.2 of data-reify uses StableNames, and is much faster. Version 0.3 provided two versions of MuRef, the mono-typed version, for trees of a single type, and the dynamic-typed version, for trees of different types. © 2009-2014 Andy Gill & Conal Elliott; BSD3 license.