ligo/gitlab-pages/docs/tutorials/get-started/tezos-taco-shop-smart-contract.ligo
2020-02-21 18:13:09 +01:00

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type taco_supply is
record [
current_stock : nat;
max_price : tez
]
type taco_shop_storage is map (nat, taco_supply)
type return is list (operation) * taco_shop_storage
function main (const taco_kind_index : nat ; var taco_shop_storage : taco_shop_storage) : return is
block {
// Retrieve the taco_kind from the contract's storage or fail
const taco_kind : taco_supply =
case taco_shop_storage[taco_kind_index] of
Some (kind) -> kind
| None -> (failwith ("Unknown kind of taco.") : taco_supply)
end;
const current_purchase_price : tez =
taco_kind.max_price / taco_kind.current_stock;
if amount =/= current_purchase_price then
// We won't sell tacos if the amount is not correct
failwith ("Sorry, the taco you are trying to purchase has a different price");
else skip;
// Decrease the stock by 1n, because we have just sold one
taco_kind.current_stock := abs (taco_kind.current_stock - 1n);
// Update the storage with the refreshed taco_kind
taco_shop_storage[taco_kind_index] := taco_kind
} with ((nil : list (operation)), taco_shop_storage)