On Mon, 2008-01-07 at 17:24 +0100, Peter Verswyvelen wrote:
Derek Elkins wrote:
Implicit parameters add an extra argument to a function conceptually. What you need is to "add an argument" to "SF" which implicit parameters don't know how to do since SF is just some data structure. One way to deal with this is the way you deal with the same problem in Haskell without implicit parameters. (I never use implicit parameters). In that case you would use the Reader monad (transformer). Similarly, you can use an equivalent Reader/Environment arrow transformer.
Nice, I did not know that monad yet, thanks!
But can it be combined together with the arrows do/proc syntax? How would that look like?
Claude Heiland-Allen gave an example, I just want to clarify. The only reason I referred to monads is for analogy. You don't use the Reader monad or Reader monad transformer, you use an idea analogous to a monad transformer called an arrow transformer, which is what Claude does.