Haskell is a standardized purely functional programming language with non-strict semantics, named after the logician Haskell Curry. It is one of the more popular functional languages, and the lazy functional language on which the most research is being performed.
-- Paul Hudak, John Hughes, Simon Peyton Jones, Philip Wadler,
"A History of Haskell: being lazy with class"
If you do not find a package in devel:languages:haskell that was here before it is because it has "bitrotted" and nobody cared to fix it for about a year. In that case I (Peter) move those packages to d:l:h:unmaintained. See there for instructions on how to resurrect a package.