'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.
History: Version 0.1 used unsafe pointer compares. Version 0.2 of 'data-reify'
used 'StableName's, and was 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. Version 0.4 used 'Int' as
a synonym for 'Unique' rather than 'Data.Unique' for node ids, by popular
demand. Version 0.5 merged the mono-typed and dynamic version again, by using
'DynStableName', an unphantomized version of StableName.
© 2009 Andy Gill; BSD3 license.