switch to Mark's "weird way to compose traits without giving up control"

core/config/noCustomization.js

@@ -6,27 +6,28 @@ import harden from '@agoric/harden';
 
 // These methods must be paired with a mintKeeper and Assay to be a
 // full configuration that can be passed into `makeMint`.
+
+function* makePaymentTrait(_superPayment) {
+  yield harden({});
+}
+
+function* makePurseTrait(_superPurse) {
+  yield harden({});
+}
+
+function* makeMintTrait(_superMint) {
+  yield harden({});
+}
+
+function* makeIssuerTrait(_superIssuer) {
+  yield harden({});
+}
+
 const noCustomization = harden({
-  makeCustomPayment(superPayment) {
-    return harden({
-      ...superPayment,
-    });
-  },
-  makeCustomPurse(superPurse) {
-    return harden({
-      ...superPurse,
-    });
-  },
-  makeCustomMint(superMint) {
-    return harden({
-      ...superMint,
-    });
-  },
-  makeCustomIssuer(superIssuer) {
-    return harden({
-      ...superIssuer,
-    });
-  },
+  makePaymentTrait,
+  makePurseTrait,
+  makeMintTrait,
+  makeIssuerTrait,
 });
 
 export { noCustomization };

core/config/seatConfig.js

@@ -17,33 +17,35 @@ import { seatStrategy } from './strategies/seatStrategy';
  */
 function makeSeatConfigMaker(makeUseObjForPayment, makeUseObjForPurse) {
   function makeSeatConfig() {
+    function* makePaymentTrait(_superPayment, issuer) {
+      const payment = yield harden({
+        // This creates a new use object which destroys the payment
+        unwrap: () => makeUseObjForPayment(issuer, payment),
+      });
+      return payment;
+    }
+
+    function* makePurseTrait(_superPurse, issuer) {
+      const purse = yield harden({
+        // This creates a new use object which empties the purse
+        unwrap: () => makeUseObjForPurse(issuer, purse),
+      });
+      return purse;
+    }
+
+    function* makeMintTrait(_superMint) {
+      return yield harden({});
+    }
+
+    function* makeIssuerTrait(_superIssuer) {
+      return yield harden({});
+    }
+
     return harden({
-      makeCustomPayment(superPayment, issuer) {
-        const payment = harden({
-          ...superPayment,
-          // This creates a new use object which destroys the payment
-          unwrap: () => makeUseObjForPayment(issuer, payment),
-        });
-        return payment;
-      },
-      makeCustomPurse(superPurse, issuer) {
-        const purse = harden({
-          ...superPurse,
-          // This creates a new use object which empties the purse
-          unwrap: () => makeUseObjForPurse(issuer, purse),
-        });
-        return purse;
-      },
-      makeCustomMint(superMint) {
-        return harden({
-          ...superMint,
-        });
-      },
-      makeCustomIssuer(superIssuer) {
-        return harden({
-          ...superIssuer,
-        });
-      },
+      makePaymentTrait,
+      makePurseTrait,
+      makeMintTrait,
+      makeIssuerTrait,
       makeMintKeeper: makeCoreMintKeeper,
       strategy: seatStrategy,
     });

core/issuers.js

@@ -25,10 +25,10 @@ Description must be truthy: ${description}`;
   // Each of these methods is used below and must be defined (even in
   // a trivial way) in any configuration
   const {
-    makeCustomIssuer,
-    makeCustomPayment,
-    makeCustomPurse,
-    makeCustomMint,
+    makeIssuerTrait,
+    makePaymentTrait,
+    makePurseTrait,
+    makeMintTrait,
     makeMintKeeper,
     strategy,
   } = makeConfig();
@@ -65,10 +65,15 @@ Description must be truthy: ${description}`;
       },
     });
 
-    // makeCustomPayment is defined in the passed-in configuration and
-    // can add additional methods to (or even override, though this is
-    // firmly discouraged) the corePayment methods
-    const payment = makeCustomPayment(corePayment, issuer);
+    // makePaymentTrait is defined in the passed-in configuration and adds
+    // additional methods to corePayment
+    const makePaymentTraitIter = makePaymentTrait(corePayment, issuer);
+    const paymentTrait = makePaymentTraitIter.next().value;
+    const payment = harden({
+      ...paymentTrait,
+      ...corePayment,
+    });
+    makePaymentTraitIter.next(payment);
 
     // ///////////////// commit point //////////////////
     // All queries above passed with no side effects.
@@ -96,10 +101,15 @@ Description must be truthy: ${description}`;
         return name;
       },
     });
-    // makeCustomPayment is defined in the passed-in configuration and
-    // can add additional methods to (or even override, though this is
-    // firmly discouraged) the corePayment methods
-    const payment = makeCustomPayment(corePayment, issuer);
+    // makePaymentTrait is defined in the passed-in configuration and adds
+    // additional methods to corePayment
+    const makePaymentTraitIter = makePaymentTrait(corePayment, issuer);
+    const paymentTrait = makePaymentTraitIter.next().value;
+    const payment = harden({
+      ...paymentTrait,
+      ...corePayment,
+    });
+    makePaymentTraitIter.next(payment);
 
     // ///////////////// commit point //////////////////
     // All queries above passed with no side effects.
@@ -219,10 +229,15 @@ Description must be truthy: ${description}`;
     },
   });
 
-  // makeCustomIssuer is defined in the passed-in configuration and
-  // can add additional methods to (or even override, though this is
-  // firmly discouraged) the coreIssuer methods
-  const issuer = makeCustomIssuer(coreIssuer);
+  // makeIssuerTrait is defined in the passed-in configuration and adds
+  // additional methods to coreIssuer.
+  const makeIssuerTraitIter = makeIssuerTrait(coreIssuer);
+  const issuerTrait = makeIssuerTraitIter.next().value;
+  const issuer = harden({
+    ...issuerTrait,
+    ...coreIssuer,
+  });
+  makeIssuerTraitIter.next(issuer);
 
   const label = harden({ issuer, description });
 
@@ -289,20 +304,30 @@ Description must be truthy: ${description}`;
         },
       });
 
-      // makeCustomPurse is defined in the passed-in configuration and
-      // can add additional methods to (or even override, though this is
-      // firmly discouraged) the corePurse methods
-      const purse = makeCustomPurse(corePurse, issuer);
+      // makePurseTrait is defined in the passed-in configuration and
+      // adds additional methods to corePurse
+      const makePurseTraitIter = makePurseTrait(corePurse, issuer);
+      const purseTrait = makePurseTraitIter.next().value;
+      const purse = harden({
+        ...purseTrait,
+        ...corePurse,
+      });
+      makePurseTraitIter.next(purse);
 
       purseKeeper.recordNew(purse, initialBalance);
       return purse;
     },
   });
 
-  // makeCustomMint is defined in the passed-in configuration and
-  // can add additional methods to (or even override, though this is
-  // firmly discouraged) the coreMint methods
-  const mint = makeCustomMint(coreMint, issuer, assay, mintKeeper);
+  // makeMintTrait is defined in the passed-in configuration and
+  // adds additional methods to coreMint
+  const makeMintTraitIter = makeMintTrait(coreMint, issuer, assay, mintKeeper);
+  const mintTrait = makeMintTraitIter.next().value;
+  const mint = harden({
+    ...mintTrait,
+    ...coreMint,
+  });
+  makeMintTraitIter.next(mint);
 
   return mint;
 }