[plt-scheme] polymorphism of primitive types

I was wrong. R5RS says:

> library procedure:  (map proc list1 list2 ...) 
>
> The lists must be lists, and proc must be a procedure taking as many 
> arguments as there are lists and returning a single value. If more 
> than one list is given, then they must all be the same length.

So this means you must redefine map for cyclic lists just as you must 
for streams.

Mea culpa -- Matthias