! Refactor (assembler): Chance constant prefix from '=' to '#'

'=' could be confusing when referencing a constant, since it looks like assignment

'#' is hopefully clearer (by analog to #hashtags)

Breaking change!

assembler.js

@@ -14,6 +14,7 @@ exports.assemble = (str, debug = false) => {
 }
 
 const POINTER_TO_CURRENT_ADDR_PSEUDO_OPERAND = '*addr';
+const CONSTANT_PREFIX = '#';
 
 const mnemonicsWithOptionalArgs = ['end', 'nop'];
 const mnemonics2opcodes = {
@@ -86,8 +87,7 @@ function decodeInstructions(line) {
     let addressingMode = 'direct'; // Must be "direct" or "indirect"
 
     // Handle constant definitions
-    if (opName.startsWith('=')) {
+    if (opName.startsWith(CONSTANT_PREFIX)) {
-      // TODO: validate constant
       // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
       let constantName = opName.substring(1).toLowerCase(); // strip '>'
       let constantValue = arg_str;
@@ -136,7 +136,7 @@ function decodeInstructions(line) {
       dbg(2, `arg_num: ${num2hex(arg_num)}`);
 
     // Handle references to constants
-    } else if (arg_str.startsWith('=')) {
+    } else if (arg_str.startsWith(CONSTANT_PREFIX)) {
       // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
       arg_str = arg_str.substring(1).toLowerCase(); // strip '>'
       dbg(2, `operand references '${arg_str}'`);
@@ -144,9 +144,9 @@ function decodeInstructions(line) {
       dbg(2, `arg_str from '${arg_str}'`);
     
     // Handle references to constants in indirect mode
-    } else if (arg_str.startsWith("(=")) {
+    } else if (arg_str.startsWith(`(${CONSTANT_PREFIX}`)) {
       addressingMode = "indirect";
-      arg_str = arg_str.replace("(=", "");
+      arg_str = arg_str.replace(`(${CONSTANT_PREFIX}`, "");
       arg_str = arg_str.replace(")", "");
       // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
       arg_str = arg_str.toLowerCase();

readme.md

@@ -88,10 +88,10 @@ With verbose debugging output:
                     ; the label will be replaced with
                     ; the address of the label
 
-    =foo $FF        ; define a constant
+    #foo $FF        ; define a constant
                     ; (must be defined before it is referenced)
     
-    ADD =foo        ; use a constant as an operand
+    ADD #foo        ; use a constant as an operand
 
     LDA *ADDR       ; `*ADDR` is a magic value referencing the memory address
                     ; that the current line will store at after assembly

test-programs/constants.asm

@@ -1,6 +1,6 @@
 ;; Test constants
-=foo $01
+#foo $01
-=bar $02
+#bar $02
-ADD =foo
+ADD #foo
-STO =bar
+STO #bar
-STO (=bar)
+STO (#bar)

test-programs/referencing-addr-during-assembly.asm

@@ -1,13 +1,13 @@
 ;; Test referencing address of line being assembled
 
 NOP ; Push the const below to a later address
-=initAddr *ADDR
+#initAddr *ADDR
 
 LDA *ADDR
 STO $25
 FHP 0   ; hop if carry set
  JMP @setCarry
-LDA =initAddr
+LDA #initAddr
 END
 
 @setCarry