From 4dda5881ef83c433fb4d3fb2c942054fb205843e Mon Sep 17 00:00:00 2001
From: n loewen <nick@nloewen.com>
Date: Wed, 16 Aug 2023 09:38:18 +0100
Subject: [PATCH] Refactor (assembler): Define label prefix in a constant, for
 easy re-configuration

---
 assembler.js | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/assembler.js b/assembler.js
index f20f4a9..7258f68 100644
--- a/assembler.js
+++ b/assembler.js
@@ -13,8 +13,10 @@ exports.assemble = (str, debug = false) => {
   return decodeInstructions(str);
 }
 
+// Configure pseudo-ops:
 const POINTER_TO_CURRENT_ADDR_PSEUDO_OPERAND = '*addr';
 const CONSTANT_PREFIX = '#';
+const LABEL_PREFIX = '@';
 
 const mnemonicsWithOptionalArgs = ['end', 'nop'];
 const mnemonics2opcodes = {
@@ -60,10 +62,10 @@ function decodeInstructions(line) {
     // HANDLE OPS
 
     // Handle label definitions
-    if (line.startsWith('@')) {
+    if (line.startsWith(LABEL_PREFIX)) {
       // TODO: validate label
       // validateLabel(line);
-      let label = line.substring(1); // strip '@'
+      let label = line.substring(1); // strip label prefix
 
       if (label in labels) {
         labels[label].pointsToByte = IP;
@@ -112,9 +114,9 @@ function decodeInstructions(line) {
     // HANDLE OPERANDS
 
     // Handle references to labels
-    } else if (arg_str.startsWith('@')) {
+    } else if (arg_str.startsWith(LABEL_PREFIX)) {
       // TODO: validate label // validateLabel(line);
-      let label = arg_str.substring(1); // strip '@'
+      let label = arg_str.substring(1); // strip label prefix
       arg_num = 0;
 
       if (label in labels) {
@@ -189,7 +191,7 @@ function decodeInstructions(line) {
 
   // Backfill label references
   for (let k of Object.keys(labels)) {
-    dbgGroup(2, `@${k}`);
+    dbgGroup(2, `${LABEL_PREFIX}${k}`);
     let label = labels[k];
     dbg(2, `pointsToByte: ${label.pointsToByte}`);
     dbg(2, `bytesToReplace: ${label.bytesToReplace}`);