Disallow "." as a local label

Fixes #760

src/asm/lexer.c

@@ -287,7 +287,9 @@ static struct KeywordMapping {
 	{"PUSHO", T_POP_PUSHO},
 	{"POPO", T_POP_POPO},
 
-	{"OPT", T_POP_OPT}
+	{"OPT", T_POP_OPT},
+
+	{".", T_PERIOD},
 };
 
 static bool isWhitespace(int c)
@@ -576,7 +578,7 @@ struct KeywordDictNode {
 	uint16_t children[0x60 - ' '];
 	struct KeywordMapping const *keyword;
 /* Since the keyword structure is invariant, the min number of nodes is known at compile time */
-} keywordDict[350] = {0}; /* Make sure to keep this correct when adding keywords! */
+} keywordDict[351] = {0}; /* Make sure to keep this correct when adding keywords! */
 
 /* Convert a char into its index into the dict */
 static inline uint8_t dictIndex(char c)

src/asm/parser.y

@@ -460,6 +460,7 @@ enum {
 %token	<nConstValue>	T_NUMBER "number"
 %token	<tzString>	T_STRING "string"
 
+%token	T_PERIOD "."
 %token	T_COMMA ","
 %token	T_COLON ":"
 %token	T_LBRACK "[" T_RBRACK "]"

test/asm/period.asm

@@ -0,0 +1,5 @@
+section "period", rom0
+
+global1: db 1
+.local   db 2
+.        db 3

test/asm/period.err

@@ -0,0 +1,3 @@
+ERROR: period.asm(5):
+    syntax error, unexpected .
+error: Assembly aborted (1 errors)!

test/asm/period.simple.err

@@ -0,0 +1,3 @@
+ERROR: period.asm(5):
+    syntax error
+error: Assembly aborted (1 errors)!

test/asm/undefined-dot.asm

@@ -1,3 +0,0 @@
-SECTION "sec", ROM0
-foo:
-	add sp, .

test/asm/undefined-local.asm

@@ -0,0 +1,3 @@
+SECTION "sec", ROM0
+foo:
+	add sp, .bar ; rgblink gives an "Unknown symbol" error here