Visual model

Parse an address

Follow one array address from left to right

Each bracket narrows the location until the engine reaches one value.

Step 1 of 1

Existing inventory record Store 01 already has 20 apples

store_01→apple→quantity20

This operation reads the stored value; it does not write 20.

currentInventory—

currentItem—

currentQuantity—

Rootglobal.invMain data tree

CollectioninventoriesOwners

Inventory IDstore_01Selected owner

CollectionitemsOwned records

Item IDappleSelected item

Fieldquantity20

The final cell is copied into currentQuantity. —

Top-level script → inv_transfer

Source inventory

🏪 Store 01

store_01

🍎 Apples20

🍎 × 3

Destination inventory

🎒 Player bag

player_bag

🍎 Apples4

Amount is greater than 0

Source has enough stock

Stock rows use central_warehouse while “You own” rows use player_bag

Shop A view

Market stall

stock ID: central_warehouse

Stock available—

You own—

Shop B view

Harbor stall

stock ID: central_warehouse

Stock available—

You own—

Authoritative inventory

🏭 Central warehouse

central_warehouse

🍎 Apple quantity50

Destination

🎒 Player bag

player_bag

🍎 Apples4

🍎 × 1

Inventory record

🎒 Player bag

items → potion

🧪 Quantity1

⚙

use_item

Checks ownership, fetches a definition, consumes one item, and applies the effect.

🧪 potion

Catalog definition

🧪 Potion

catalog → potion

Healing25

Weight2

Base price12

Gameplay system

Player health

Current health60 / 100

Bad: duplicate persistent valuesCan drift

Inventory array4

→

HUD stored globalpersistent duplicate4

Inventory-menu stored globalpersistent duplicate4

The copies are separate facts after initialization.

Good: readers ask one authorityOne truth

Inventory array4

→

HUD render resultwhen the HUD refreshes—

Inventory-menu resultwhen the item list refreshes—

Readers fetch the current value when they need it.

Interactive model

One item moves between two authoritative records

Source

Store 01

store_01

🍎 Apples20

Destination

Player bag

player_bag

🍎 Apples4

EFPSE script

Transfer procedure and request

The request supplies two owner IDs, one item ID, and an amount. The procedure reads the source and updates both inventories.

Transfer procedurereads, validates, and writes both inventory records

procedure inv_transfer
invTransferSuccess=0
sourceQuantity=$global.inv["inventories"][$invTransferFrom]["items"][$invTransferItem]["quantity"]
if $invTransferAmount > 0 {
    if $sourceQuantity >= $invTransferAmount {
        global.inv["inventories"][$invTransferFrom]["items"][$invTransferItem]["quantity"]-=$invTransferAmount
        global.inv["inventories"][$invTransferTo]["items"][$invTransferItem]["quantity"]+=$invTransferAmount
        invTransferSuccess=1
    }
}
end

Transfer requestsupplies the four values used by this transfer

invTransferFrom="store_01"
invTransferTo="player_bag"
invTransferItem="apple"
invTransferAmount=3
call inv_transfer

Live values

Interactive model

Each display row reads the inventory that owns its value

Shop A view

Market stall

central_warehouse

Stock available50

You own4

Shop B view

Harbor stall

central_warehouse

Stock available50

You own4

Warehouse authority

🏭 Central warehouse

central_warehouse

🍎 Apples50

Independent stock

🏬 Store 02

store_02

🍎 Apples7

Destination

🎒 Player bag

player_bag

🍎 Apples4

EFPSE script

Stock-owner reads + player-owner reads + purchase contexts

Stock rows read the shop’s configured stock inventory. “You own” rows read player_bag.

View configurationstock IDs used by the two shop views

shopAStockId="central_warehouse"
shopBStockId="central_warehouse"

Refresh the shop viewsstock and ownership come from different owner IDs

activeShopStockId=$shopAStockId
shopAStockQuantity=$global.inv["inventories"][$activeShopStockId]["items"]["apple"]["quantity"]
shopAOwnedQuantity=$global.inv["inventories"]["player_bag"]["items"]["apple"]["quantity"]

activeShopStockId=$shopBStockId
shopBStockQuantity=$global.inv["inventories"][$activeShopStockId]["items"]["apple"]["quantity"]
shopBOwnedQuantity=$global.inv["inventories"]["player_bag"]["items"]["apple"]["quantity"]

Purchase proceduremoves one apple from active stock to player_bag

procedure shop_buy_apple
invTransferFrom=$activeShopStockId
invTransferTo="player_bag"
invTransferItem="apple"
invTransferAmount=1
call inv_transfer
end

Shop A purchaseuses Shop A’s configured stock ID

activeShopStockId=$shopAStockId
call shop_buy_apple

Shop B purchaseuses Shop B’s configured stock ID

activeShopStockId=$shopBStockId
call shop_buy_apple

Live values