[Haskell] ANNOUNCE: multirec-0.1
andres at cs.uu.nl
Fri Oct 31 10:48:48 EDT 2008
multirec: Generic programming with systems of recursive datatypes
Many generic programs require information about the recursive positions
of a datatype. Examples include the generic fold, generic rewriting or
the Zipper data structure. Several generic programming systems allow to
write such functions by viewing datatypes as fixed points of a pattern
functor. Traditionally, this view has been limited to so-called regular
datatypes such as lists and binary trees. In particular, systems of
mutually recursive datatypes have been excluded.
With the multirec library, we provide a mechanism to talk about fixed
points of systems of datatypes that may be mutually recursive. On top
of this representations, generic functions such as the fold or the Zipper
can then be defined.
We expect that the library will be especially interesting for compiler
writers, because ASTs are typically systems of mutually recursive datatypes,
and with multirec it becomes easy to write generic functions on ASTs.
The library is based on ideas described in the paper:
Alexey Rodriguez, Stefan Holdermans, Andres Löh, Johan Jeuring
Generic programming with fixed points for mutually recursive datatypes
Technical Report, Universiteit Utrecht
* Generalizes the fixed point view from single, regular datatypes to systems
of recursive datatypes.
* Includes detailed examples: generic fold and generic compos, the latter
in the style of
Björn Bringert, Arne Ranta
A pattern for almost compositional functions
The Zipper and generic rewriting for systems of datatypes
will be released soon as separate libraries that build on multirec.
* The generic compos functions do not require the user to modify
their existing systems of datatypes.
* In its current form, this library does not support nested datatypes.
* GHC 6.8.3 or later
* Cabal 1.2.1 or later
cabal install multirec
Get the package:
Get the source:
svn checkout https://svn.cs.uu.nl:12443/repos/dgp-haskell/multirec/trunk
Bugs & Support
Report issues, request features, or just discuss the library with the
authors, maintainers, and other interested persons at:
Andres Loeh, Universiteit Utrecht
mailto:andres at cs.uu.nl mailto:mail at andres-loeh.de
More information about the Haskell