rec-def (hackage): This library provides safe APIs that allow you to define and calculate values recursively, and still get a result out:  will not loop, but rather produces the set fromList [23,42]  See Data.Recursive.Examples for more examples, or just browse the modules  Data.Recursive.Bool  Data.Recursive.Set  Data.Recursive.Map  Data.Recursive.DualBool  More APIs (e.g. for maps or Natural) can be added over time, as need and good use-cases arise.  For the (unsafe) building blocks to build such APIs, see  Data.Propagator.Purify for the wrapper that turns an IO-implemented propagator into a pure data structure  Data.Propagator.Naive for a naive propagator implementation  Data.Propagator.P2 for a smarter propagator implementation for the two-point lattice, i.e. Bool  The library is not (yet) focussed on performance, and uses a rather naive propagator implementation. Expect this to be slow if you have large graphs. This may be improved in the future (e.g. by propagating only deltas, and accumulating deltas before applying a function), but for now the focus is on foremost providing this capability in the first place and getting the user-facing API right.
Keywords: bsd2|data|library