Hi there,
I'm new here, so sorry if I'm stating the obvious.
On Nov 1, 2007 2:46 PM, apfelmus
Stefan Holdermans wrote:
Exposing uniqueness types is, in that sense, just an alternative to monadic encapsulation of side effects.
While *World -> (a, *World) seems to work in practice, I wonder what its (denotational) semantics are. I mean, the two programs
loop, loop' :: *World -> ((),*World)
loop w = loop w loop' w = let (_,w') = print "x" w in loop' w'
both have denotation _|_ but are clearly different in terms of side effects. (The example is from SPJs awkward-squad tutorial.) Any pointers?
For side-effecting program one has to consider bisimilarity. It's common that semantically equivalent (under operational or denotational semantics) behave differently with regard to side-effects (i/o) - i.e. they are not bisimilar. http://en.wikipedia.org/wiki/Bisimulation Arnar