Items: take and drop

A unit is a portable storage slot: one kind of item, a few places and a compulsory delay between trips

mediumYou need: Arrival: within, Items and an empty answer

steptick 0

Unit Bind0

type

Unit Control1

typeitem takefromitemamount

Sensor2

=

 in

Sensor3

=

 in

Sensor4

=

 in

@counter0number

cargonullnull

whatnullnull

inStorenullnull

ucontrol itemTake container1 @copper 10 0 0

The poly takes copper out of the store: cargo grows, inStore shrinks. Once the unit is full — and a poly has thirty places — taking stops changing anything.

Field	itemTake	itemDrop
second	where from: a building	where to: a building
third	which item	how many to hand over
fourth	how many to take	—

The difference in fields is no accident: only one kind of item can be taken, and which one has to be said; what a unit hands over is whatever it has — there is nothing to choose from.

Three rules of transfer

Only up close. Transfer works within about six tiles of the building — roughly as far as a player can drag things by hand. The unit is brought in with move first, and only then given the transfer order.

No more often than once every one and a half seconds. Ninety ticks pass between one unit’s two transfers. An order given sooner simply does nothing: no error, no half transfer.

Only your own. Another team’s store will not give to a unit and will not accept from it — the order silently does nothing.

Silent failure

A transfer does not report a refusal. The unit is too far, the store is full, the delay has not passed, the item has run out — in every case itemTake behaves identically: it says nothing.

Check by the facts: sensor cargo @unit @totalItems before and after. If the cargo did not change, the transfer did not happen, and it is worth finding out why rather than assuming it worked.

A unit carries one kind of item

Unlike a store, a unit has one cargo slot: it carries copper or graphite, but not both at once. Take copper and then try to take graphite, and there will be no graphite.

Property	What it gives
@totalItems	how much it carries in total
@firstItem	what exactly it carries: @copper, @graphite or emptiness
@itemCapacity	how much fits: 30 on a poly, 20 on a mono, 60 on a mega

A full trip

steptick 0

Unit Bind0

type

Sensor1

=

 in

Jump -> 62

if >=

Unit Control3

typemovexy

Unit Control4

typeitem takefromitemamount

End5

Unit Control6

typemovexy

Unit Control7

typeitem droptoamount

Sensor8

=

 in

@counter0number

cargonullnull

deliverednullnull

Here is a whole ferry program. It looks at its cargo and decides where to fly: empty — to the store for copper, full — to the recipient.

ubind @poly
sensor cargo @unit @totalItems
jump 6 greaterThanEq cargo 30
ucontrol move 5 4 0 0 0
ucontrol itemTake container1 @copper 30 0 0
end
ucontrol move 15 4 0 0 0
ucontrol itemDrop container2 30 0 0 0

Three trips and ninety copper have moved into the second store. Note that there is no within and no waiting here at all: the transfer order is issued every iteration and fires by itself as soon as the unit arrives and the delay has passed. Such a ferry is shorter and more reliable than a program that honestly waits for arrival.

Note

Dumping cargo on the ground is ucontrol itemDrop @air 0 0 0 0. The items vanish, and there is no delay on it. It is rarely needed: freeing a unit of unwanted ore before sending it after something else, for instance.

Remember

• itemTake store item count takes, itemDrop store count gives.
• Transfer works only right next to a building and no more than once every one and a half seconds.
• Nobody reports a refusal — check with @totalItems.
• A unit carries one kind of item; which one is in @firstItem.
• itemDrop @air dumps the cargo on the ground.

Task

In the first example change @copper to @lead: the cargo stops growing — there is no lead in the store, and itemTake silently does nothing.

In the second example change the target in the fourth line to 15 4 — the same place the cargo is delivered to. The unit stops flying for copper, hangs by the second store, and the ferrying stops at whatever has already been delivered.