aka roll0 + roll1 + roll2

I mentioned it because it's the sort of thing someone might mindlessly
reorder, knowing that addition is commutive. (They might reorder the
statement sequence, but they'd be acting against the ordinary
expectation that statement sequence matters.)

We have that in common. Of course, what we write may be read by others
less-adept.

The thing that I was curious about is that the obvious concern you have
for expressing the domain detail (frameFirstBall etc) seemed to
lose-out against the side-effects of the "peek" metaphor.

The usual solution for the trivial version of the bowling game, in a
language which support pattern-matching on lists:

Start = score [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,10,5,3] 0 0

score rolls total 10 = total
score [x,y] total frame = total+x+y
score [x,y,z:rest] total frame
| x == 10    = score [y,z:rest] (total+x+y+z) frameCount
| x+y == 10  = score [z:rest]   (total+x+y+z) frameCount
| otherwise  = score [z:rest]   (total+x+y)   frameCount
where frameCount = frame+1

http://groups-beta.google.com/group/comp.object/msg/45ed159928b69648

Better to get Paul Sinnett to write about his refactoring
http://groups-beta.google.com/group/comp.object/msg/0212c8de1848cd11