Robust Lists

First off, SHAME!

Secondly, the eager implementation of this thing does not gel with the laziness of the data structure.  There's so much unnecessary evaluation of the list it makes it almost meaningless as a data structure compared to the built-in one.  We can "fix" that with recursion but then we'd lose both the magic of benign effects and any control over the performance of each of the combinators.

Rock and a hard place, eh?