Wed Aug 19 08:43:40 CEST 2009

GC and read -> need C suspensions

Because ports are stateful entities, the read operation might interact
badly with GC restarts.

It might be necessary to construct an intermediate representation.
The real solution however is to make the reader communicate externally
at everything which is now a CONS, so it never sees scheme values.

I guess this can be made to work, so I'm going to stick to the current
version, since that change would be transparent once context switching
is implemented.