polyEqual

[Matthew Fluet]

> I had thought a bit about this code, and my current feeling is that if
> I were to rewrite it, I would make the DirectExp syntax tree an
> explicit datatype, and move the linearization algorithm all into one
> place.  Using all the higher-order stuff is cute, but I don't think it
> really buys much, and I think it is harder to understand.  It would at
> least make an interesting comparison.

It did take me a couple of looks until I got the whole picture; but it
wasn't so bad once I realized it was just continuation-passing.