Pure functions in D

[Walter Bright]

downs wrote:
> Just build a new executable, halt all your running tasks, dump the
> system state to a file (*including socket handles*), use the exec
> system call to replace the process with the new executable, and read
> the system state back, replacing handles as you go.
> 
> No dropped connections.

I've done that with C/C++ code before. The trouble is finding *all* of 
the state that matters in order to save/restore it. It can be done, but 
it is tedious and very error prone.

But with pure functions, it's a no-brainer.