From 50c43acc3de8117a9993f53f71b8fb59418b6f45 Mon Sep 17 00:00:00 2001
From: Kate Sills <kate@agoric.com>
Date: Thu, 15 Aug 2019 15:19:02 -0700
Subject: [PATCH] make the `makeMint` config more trait-like (#98)

---
 core/config/noCustomization.js | 16 +++++------
 core/issuers.js                | 49 ++++++++++++++++++++--------------
 more/pixels/pixelConfig.js     | 12 +++------
 3 files changed, 41 insertions(+), 36 deletions(-)

diff --git a/core/config/noCustomization.js b/core/config/noCustomization.js
index 55a008a61c4..1f7983a08c1 100644
--- a/core/config/noCustomization.js
+++ b/core/config/noCustomization.js
@@ -7,17 +7,17 @@ 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`.
 const noCustomization = harden({
-  makeCustomPayment(superPayment) {
-    return superPayment;
+  makePaymentTrait(_superPayment) {
+    return harden({});
   },
-  makeCustomPurse(superPurse) {
-    return superPurse;
+  makePurseTrait(_superPurse) {
+    return harden({});
   },
-  makeCustomMint(superMint) {
-    return superMint;
+  makeMintTrait(_superMint) {
+    return harden({});
   },
-  makeCustomIssuer(superIssuer) {
-    return superIssuer;
+  makeIssuerTrait(_superIssuer) {
+    return harden({});
   },
 });
 
diff --git a/core/issuers.js b/core/issuers.js
index 680df0a1970..7e370d07daa 100644
--- a/core/issuers.js
+++ b/core/issuers.js
@@ -24,10 +24,10 @@ 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,
     makeAssay,
   } = makeConfig();
@@ -52,10 +52,12 @@ Description must be truthy: ${description}`;
       },
     });
 
-    // makeCustomPayment is defined in the passed-in configuration and
-    // allows for the customization of the payment, including adding
-    // additional methods
-    const payment = makeCustomPayment(corePayment, issuer);
+    // makePaymentTrait is defined in the passed-in configuration and adds
+    // additional methods to corePayment
+    const payment = harden({
+      ...makePaymentTrait(corePayment, issuer),
+      ...corePayment,
+    });
 
     // ///////////////// commit point //////////////////
     // All queries above passed with no side effects.
@@ -115,10 +117,12 @@ Description must be truthy: ${description}`;
     },
   });
 
-  // makeCustomIssuer is defined in the passed-in configuration and
-  // allows for the customization of the issuer, including adding
-  // additional methods
-  const issuer = makeCustomIssuer(coreIssuer);
+  // makeIssuerTrait is defined in the passed-in configuration and adds
+  // additional methods to coreIssuer.
+  const issuer = harden({
+    ...makeIssuerTrait(coreIssuer),
+    ...coreIssuer,
+  });
 
   const label = harden({ issuer, description });
 
@@ -189,19 +193,24 @@ Description must be truthy: ${description}`;
         },
       });
 
-      // makeCustomPurse is defined in the passed-in configuration and
-      // allows for the customization of the purse, including adding
-      // additional methods
-      const purse = makeCustomPurse(corePurse, issuer);
+      // makePurseTrait is defined in the passed-in configuration and
+      // adds additional methods to corePurse
+      const purse = harden({
+        ...makePurseTrait(corePurse, issuer),
+        ...corePurse,
+      });
+
       purseKeeper.recordNew(purse, initialBalance);
       return purse;
     },
   });
 
-  // makeCustomMint is defined in the passed-in configuration and
-  // allows for the customization of the mint, including adding
-  // additional methods
-  const mint = makeCustomMint(coreMint, issuer, assay, mintKeeper);
+  // makeMintTrait is defined in the passed-in configuration and
+  // adds additional methods to coreMint
+  const mint = harden({
+    ...makeMintTrait(coreMint, issuer, assay, mintKeeper),
+    ...coreMint,
+  });
 
   return mint;
 }
diff --git a/more/pixels/pixelConfig.js b/more/pixels/pixelConfig.js
index 32a4dabed2b..45639f07e04 100644
--- a/more/pixels/pixelConfig.js
+++ b/more/pixels/pixelConfig.js
@@ -61,9 +61,8 @@ function makePixelConfigMaker(
     }
 
     return harden({
-      makeCustomPayment(superPayment, issuer) {
+      makePaymentTrait(superPayment, issuer) {
         return harden({
-          ...superPayment,
           // This creates a new use object on every call. Please see
           // the gallery for the definition of the use object that is
           // created here by calling `makeUseObj`
@@ -88,9 +87,8 @@ function makePixelConfigMaker(
           },
         });
       },
-      makeCustomPurse(superPurse, issuer) {
+      makePurseTrait(superPurse, issuer) {
         return harden({
-          ...superPurse,
           // This creates a new use object on every call. Please see
           // the gallery for the definition of the use object that is
           // created here by calling `makeUseObj`
@@ -111,9 +109,8 @@ function makePixelConfigMaker(
           },
         });
       },
-      makeCustomMint(superMint, issuer, assay, mintKeeper) {
+      makeMintTrait(_superMint, issuer, assay, mintKeeper) {
         return harden({
-          ...superMint,
           // revoke destroys the amount from this mint and calls
           // revoke on the childMint with an amount of the same
           // quantity. Destroying the amount depends on the fact that
@@ -131,9 +128,8 @@ function makePixelConfigMaker(
           },
         });
       },
-      makeCustomIssuer(superIssuer) {
+      makeIssuerTrait(superIssuer) {
         return harden({
-          ...superIssuer,
           // The parent issuer is one level up in the chain of
           // issuers.
           getParentIssuer() {