Yes, these techniques are fairly well known now, and hopefully some of
the more experienced Haskellers are using them (I certainly use the
non-empty list tricks). Any anyone with more than 6 months Haskell knows
to avoid fromJust.

The problem I see is that head/fromJust errors are usually caused by
*beginner* Haskellers, who don't know the techniques for statically
avoiding them.

I'm one of those "beginning" Haskellers (about one month in) and I'd like to know these techniques. Are they written up anywhere?

Justin

p.s. apologies for the double-email Donald - forget to CC the list on the first one.