Ideas about autopickup 

1) fourba implemented: in the drop menu, press '\' to drop and turn off
autopickup. I think this is basically a good idea and there is no reason
not to include it, but there may be easier ways to let the player drop and
control autopickup.

2) I thought fourba implemented: in the autopickup menu, turning something
off also drops it. I think this is a good idea but would want to
be optional because it's bound to mess up someone's gameplay. In
particular right now interacting with \ consumes no turns and it could
provide some unpleasant surprises if this was implemented (you wouldn't
drop with monsters in view, but you might with them in pursuit...)

3) I suggested: an option that pressing D, drop last item, also turns off
autopickup of that item. I think this is a good idea (but I would).

4) Yermak suggests: essentially the inventory embodies autopickup, and
dropping an item always turns off autopickup. I don't like this; I drop
items at the entrance to portal branches to make space, the most obvious
way it would catch me out. That's not to say it's a bad idea, but I
wouldn't use it so would be upset if it were not optional.

All of these ideas are problematic around those autopickup categories
that cover multiple items (mostly ammo, since one practically never wants
not to autopickup books). In practice I personally find I almost never
turn these on.

#1 is harmless - don't press the special key, and you won't turn off the
category.

#2 could be annoying. I somehow turned on autopickup tomahawks. I go to
turn it off because I don't want to clutter my inventory with exploding
tomahawks. It drops my stack of ordinary tomahawks that I did want.

#3 is kind of theoretically possibly annoying; I have some poisoned
needles but have seen no curare. I D the poisoned needles, and now won't
autopickup curare. I'm kind of inclined to say that's my own lookout for
turning on the option that makes D do this, but that's partly because it
wouldn't bite me personally anyway.

I'm not sure I understand how #4 is meant to handle edge cases well enough
to comment on this edge case.


In summary I think fourba has implemented #1, yay!, this is a good change
that we want; #2 might be nice but is arguably a bit redundant and has
potentially unwanted consequences; #3 would also be nice; I wouldn't use #4.


But! Yermak observes (correctly) that autopickup is a tristate.

This is an interaction between the "autopickup" option, which sets whether
items with a given symbol are picked up by default (eg if unknown), and the
autopickup_exceptions options and selections made in the \ menu.  The three
states are "always pickup", "never pickup", and "use the per-symbol
selection". There are then some additional rules like not picking up
useless objects or picking up matching objects which trump the per-symbol
setting but not autopickup_exceptions.

This poses a bit of a problem. Suppose '(', Missiles, is off. I have a
poisoned needle, and drop it using options #1 or #3. I also have a stack
of needles of curare. It suffices to set the tristate to "use per-symbol
selection" - with this setting, I will still pick up curare needles
because "use per-symbol selection" doesn't suppress autopickup of matching
stacks.

So far, so good. But what if '(', Missiles, was on? Then if I set the
tristate for needles to "use per-symbol selection", that does nothing at
all; I still autopickup poisoned needles. If I set it to "never", I don't
pick up curare.

Hence I think it's necessary to arrange that the game will always, no
matter what options are set, autopickup items that stack with existing
inventory.  With the removal of encumbrance, there is no reason not to
autopickup such an item. (This behaviour itself has to be optional, or
some crazy turncount speedrunner will complain, so; add an
"always_pickup_matching" option, default true, that causes matching items
to be picked up if autopickup is on at all, regardless of
autopickup_exceptions).

Now the tristate can be set to "never pickup" (regardless of the
per-symbol selection), leaving poisoned needles behind but still
picking up curare because it stacks with existing inventory.

If you turn "always_pickup_matching" off then use this
drop-and-turn-off-pickup facility, you probably still get what you wanted
because you didn't want to automatically gather extra curare needles.

(How does this interact with "pickup_thrown"? I think it would be valuable
but tedious to construct a flowchart of all autopickup behaviour.)