Refine example dialers file

This commit adds references for the example dialers file and refines it for
correctness, readability, and consistency.

example/sip010.js

@@ -1,57 +1,67 @@
+// This file contains a custom predefined post-dialer that checks the SIP-010
+// transfer function for the print event. For a token to be SIP-010 compliant,
+// its transfer function must emit the print event with the `memo` content.
+//
+// This is just an example of the power of custom dialers. In sBTC, the
+// transfer function did not emit the print event, resulting in sBTC not being
+// SIP-010 compliant. This custom dialer allows for the detection of such
+// issues for any fungible token contract in the future.
+//
+// References:
+// https://github.com/stacksgov/sips/blob/2c3b36c172c0b71369bc26cffa080e8bdd2b3b84/sips/sip-010/sip-010-fungible-token-standard.md?plain=1#L69
+// https://github.com/stacks-network/sbtc/commit/74daed379e9aad73dd09bebb83231f2c48ef4d81
+
 const { cvToHex } = require("@stacks/transactions");
 
 async function postTransferSip010PrintEvent(context) {
   const selectedFunction = context.selectedFunction;
+
   // A fungible token complies with the SIP-010 standard if the transfer event
   // always emits the print event with the `memo` content.
   if (selectedFunction.name !== "transfer") {
     return;
   }
 
-  const functionCall = context.functionCall;
-  const functionCallEvents = functionCall.events;
+  const functionCallEvents = context.functionCall.events;
 
-  if (functionCallEvents.length === 0) {
-    throw new Error(
-      "No transfer events. The transfer function must emit the SIP-010 print event!"
-    );
-  }
-
-  // The `memo` parameter is the fourth parameter of the `transfer` function.
+  // The `memo` parameter is the fourth parameter of the `rendezvous-token`'s
+  // `transfer` function.
   const memoParameterIndex = 3;
 
-  const memoArg = context.clarityValueArguments[memoParameterIndex];
+  const memoGeneratedArgumentCV =
+    context.clarityValueArguments[memoParameterIndex];
 
   // The `memo` argument is optional. If `none`, nothing has to be printed.
-  if (memoArg.type === 9) {
+  if (memoGeneratedArgumentCV.type === 9) {
     return;
   }
 
-  // The `memo` argument must be `some`. Otherwise, the generated clarity
-  // argument is invalid.
-  if (memoArg.type !== 10) {
-    return;
+  // If not `none`, the `memo` argument must be `some`. Otherwise, the
+  // generated clarity argument is not an option type, so it does not comply
+  // with the SIP-010 fungible token trait.
+  if (memoGeneratedArgumentCV.type !== 10) {
+    throw new Error("The memo argument has to be an option type!");
   }
 
   // Turn the inner value of the `some` type into a hex to compare it with the
   // print event data.
-  const hexMemoArgValue = cvToHex(memoArg.value);
+  const hexMemoArgumentValue = cvToHex(memoGeneratedArgumentCV.value);
 
   const sip010PrintEvent = functionCallEvents.find(
     (ev) => ev.event === "print_event"
   );
 
   if (!sip010PrintEvent) {
     throw new Error(
-      "No print event found. The transfer function must emit the SIP-010 print event!"
+      "No print event found. The transfer function must emit the SIP-010 print event containing the memo!"
     );
   }
 
   const sip010PrintEventValue = sip010PrintEvent.data.raw_value;
 
-  if (sip010PrintEventValue !== hexMemoArgValue) {
+  if (sip010PrintEventValue !== hexMemoArgumentValue) {
     throw new Error(
-      `The print event memo value is not equal to the memo parameter value: ${hexMemoArgValue} !== ${sip010PrintEventValue}`
+      `The print event memo value is not equal to the memo parameter value: ${hexMemoArgumentValue} !== ${sip010PrintEventValue}`
     );
   }