Add support of unnamed labels with @ (.localchar) prefix.

src/ca65/main.c

@@ -707,6 +707,24 @@ static void OneLine (void)
         NextTok ();
     }
 
+    /* Handle @-style unnamed labels */
+    if (CurTok.Tok == TOK_ULABEL) {
+        if (CurTok.IVal != 0) {
+            Error ("Invalid unnamed label definition");
+        }
+        ULabDef ();
+        NextTok ();
+
+        /* Skip the colon. If NoColonLabels is enabled, allow labels without
+        ** a colon if there is no whitespace before the identifier.
+        */
+        if (CurTok.Tok == TOK_COLON) {
+            NextTok ();
+        } else if (CurTok.WS || !NoColonLabels) {
+            Error ("':' expected");
+        }
+    }
+
     /* If the first token on the line is an identifier, check for a macro or
     ** an instruction.
     */

src/ca65/scanner.c

@@ -1124,17 +1124,33 @@ Again:
     /* Local symbol? */
     if (C == LocalStart) {
 
-        /* Read the identifier. */
+        NextChar ();
-        ReadIdent ();
 
-        /* Start character alone is not enough */
+        if (IsIdChar (C)) {
-        if (SB_GetLen (&CurTok.SVal) == 1) {
+            /* Read a local identifier */
-            Error ("Invalid cheap local symbol");
+            CurTok.Tok = TOK_LOCAL_IDENT;
-            goto Again;
+            SB_AppendChar (&CurTok.SVal, LocalStart);
+            ReadIdent ();
+        } else {
+            /* Read an unnamed label */
+            CurTok.IVal = 0;
+            CurTok.Tok = TOK_ULABEL;
+
+            if (C == '-' || C == '<') {
+                int PrevC = C;
+                do {
+                    --CurTok.IVal;
+                    NextChar ();
+                } while (C == PrevC);
+            } else if (C == '+' || C == '>') {
+                int PrevC = C;
+                do {
+                    ++CurTok.IVal;
+                    NextChar ();
+                } while (C == PrevC);
+            }
         }
 
-        /* A local identifier */
-        CurTok.Tok = TOK_LOCAL_IDENT;
         return;
     }
 
@@ -1314,22 +1330,30 @@ CharAgain:
                     break;
 
                 case '-':
+                case '<':
+                {
+                    int PrevC = C;
                     CurTok.IVal = 0;
                     do {
                         --CurTok.IVal;
                         NextChar ();
-                    } while (C == '-');
+                    } while (C == PrevC);
                     CurTok.Tok = TOK_ULABEL;
                     break;
+                }
 
                 case '+':
+                case '>':
+                {
+                    int PrevC = C;
                     CurTok.IVal = 0;
                     do {
                         ++CurTok.IVal;
                         NextChar ();
-                    } while (C == '+');
+                    } while (C == PrevC);
                     CurTok.Tok = TOK_ULABEL;
                     break;
+                }
 
                 case '=':
                     NextChar ();

src/ca65/token.h

@@ -71,7 +71,7 @@ typedef enum token_t {
     TOK_REG,            /* Sweet16 R.. register (in sweet16 mode) */
 
     TOK_ASSIGN,         /* := */
-    TOK_ULABEL,         /* :++ or :-- */
+    TOK_ULABEL,         /* An unnamed label */
 
     TOK_EQ,             /* = */
     TOK_NE,             /* <> */

src/ca65/ulabel.c

@@ -107,8 +107,12 @@ ExprNode* ULabRef (int Which)
     int     Index;
     ULabel* L;
 
-    /* Which can never be 0 */
+    /* Which should not be 0 */
-    PRECONDITION (Which != 0);
+    if (Which == 0) {
+        Error ("Invalid unnamed label reference");
+        /* We must return something valid */
+        return GenCurrentPC();
+    }
 
     /* Get the index of the referenced label */
     if (Which > 0) {