Fri May 4 12:39:26 CEST 2007

problem with tasks

i don't have task-local variables or proper dynamic wind.  a problem
seems to be to print in daemon mode: print should not spawn an output
task there!

the real solution is:

* proper dynamic-wind: any exit from a protected block should restore
  the dynamic state of a task.

in this case, it is ok for a console task to block: it just needs to
know where to send its input.

so, how to do this?

starting a task is:
- saving all variables in a temp location
- storing it's variables

stopping is the same, but reversed, so i need an operation that swaps
a list of variables, and store the saved list in a global variable.

a note about swapping tasks: why not just concentrating the swapping
on the return stack only, since i have other things to swap.. ?