On 14.02.2011, at 03:03 PM, Pavel Perikov [perikov@gmail.com] wrote: Sorely, Haskell can't prove logic with it. No predicates on values, guarantee that proof is not _|_. Haskell makes bug free software affordable, that's true. But it's not a proof assistant. Being equivalent to a class of total recursive functions, the EP (Enterprise-Participant) data model can assist users to enter arbitrary and meaningful expressions only. It is a new addition to programming languages. Check out here: http://www.froglingo.com/FroglingoPL.pdf Kevin