wren ng thornton wrote:
One of the nice things about not having a Nil is that it lets you easily be polymorphic over things ending in () ---a normal list---, (Maybe a) ---a fallible list---, (Either a b) ---your progress type---, etc. Whereas the version that has both Nil and End forces us into the (Maybe a) scenario. A side effect of this is that the (Either a b) option isn't available because we can only construct t=Mx.(x*t)+(1+a+b) not t=Mx.(x*t)+(a+b).
Er, I meant t=Mx.(c*x)+(1+a+b) vs t=Mx.(c*x)+(a+b). This is what I get for posting without coffee.
-- Live well, ~wren _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
