Feature: alpha version

.gitignore

@@ -6,3 +6,5 @@ _agstate/yarn-links/
 .parcel-cache/
 ui/.cache/
 ui/dist/
+
+.DS_Store

contract/src/simple-exchange-nondurable.js

@@ -0,0 +1,114 @@
+import { AmountShape } from '@agoric/ertp';
+import { makeNotifierKit } from '@agoric/notifier';
+import { M } from '@agoric/store';
+import '@agoric/zoe/exported.js';
+import { assertIssuerKeywords, swap } from '@agoric/zoe/src/contractSupport';
+
+// Test script
+// 1: Alice creates a simpleExchange instance and spreads the publicFacet far
+// and wide with instructions on how to call makeInvitation().
+
+// 2: Alice escrows with zoe to create a sell order. She wants to
+// sell 3 moola and wants to receive at least 4 simoleans in
+// return.
+
+// 4: Alice adds her sell order to the exchange
+
+// 5: Bob decides to join.
+
+// Bob creates a buy order, saying that he wants exactly 3 moola,
+// and is willing to pay up to 7 simoleans.
+
+// 6: Bob escrows with zoe
+// 8: Bob submits the buy order to the exchange
+
+// Alice gets paid at least what she wanted
+
+// 6: Alice deposits her payout to ensure she can
+// Alice had 0 moola and 4 simoleans.
+
+// 7: Bob deposits his original payments to ensure he can
+// Bob had 3 moola and 3 simoleans.
+
+/**
+ * @type {ContractStartFn}
+ * @param {ZCF} zcf
+ */
+const start = zcf => {
+    const { notifier, updater } = makeNotifierKit();
+
+    const sellSeats = [];
+    const buySeats = [];
+
+    const getBookOrders = () => {
+        return {
+            buys: buySeats.map(seat => seat.getProposal()),
+            sells: sellSeats.map(seat => seat.getProposal()),
+        }
+    }
+
+    const bookOrdersChanged = () => {
+        updater.updateState(getBookOrders());
+    }
+
+    const exchangeOfferHandler = seat => {
+        const { give, want } = seat.getProposal();
+        const { Asset: asset, Price: price } = give;
+        const { Asset: assetWanted, Price: priceWanted } = want;
+
+        // Check that the keywords are correct
+        assertIssuerKeywords(zcf, harden(['Asset', 'Price']));
+
+        // Check that the proposal shape is correct
+
+        //
+        // TODO: Use atomicRearrange to check that the proposal shape is correct
+        //
+        // Is this correct?
+        zcf.atomicRearrange(
+            harden([price, asset]),
+            harden([priceWanted, assetWanted]),
+        )
+
+        // // Check that the offer is satisfiable
+        // swap(zcf, { seat, gains: { Asset: assetWanted }, losses: { Price: priceWanted } });
+
+        // // Check that the offer is satisfiable
+        // swap(zcf, { seat, gains: { Price: price }, losses: { Asset: asset } });
+
+        // Add the seat to the appropriate list
+        if (assetWanted === 'Asset') {
+            sellSeats.push(seat);
+        } else {
+            buySeats.push(seat);
+        }
+
+        // Tell the notifier that there has been a change to the book orders
+        bookOrdersChanged();
+
+        // Make the seat available to the other side
+        return seat;
+    }
+
+    const makeExchangeInvitation = () =>
+        zcf.makeInvitation(exchangeOfferHandler, 'exchange', undefined, M.splitRecord(
+            {
+                give: { Asset: AmountShape },
+                want: { Price: AmountShape }
+            }
+        ));
+
+    const creatorFacet = Far('creatorFacet', {
+
+    });
+
+    const publicFacet = Far('publicFacet', {
+        makeInvitation: makeExchangeInvitation,
+        getNotifier: () => notifier,
+    });
+
+    return harden({ creatorFacet, publicFacet });
+}
+
+harden(start)
+export { start };