Allow trailing commas in bare lists

This applies to macro arguments, DB, DW, DL, DS,
PRINT, PRINTLN, EXPORT, PURGE, and OPT.

It also removes support for empty entries in DB/DW/DL.
(Deprecating it would require keeping parser support,
which is ambiguous with trailing commas.)

Fixes #753

include/asm/lexer.h

@@ -67,7 +67,6 @@ enum LexerMode {
 };
 
 void lexer_SetMode(enum LexerMode mode);
-bool lexer_IsRawMode(void);
 void lexer_ToggleStringExpansion(bool enable);
 
 uint32_t lexer_GetIFDepth(void);

include/asm/macro.h

@@ -21,7 +21,7 @@ struct MacroArgs;
 
 struct MacroArgs *macro_GetCurrentArgs(void);
 struct MacroArgs *macro_NewArgs(void);
-void macro_AppendArg(struct MacroArgs **args, char *s, bool isLastArg);
+void macro_AppendArg(struct MacroArgs **args, char *s);
 void macro_UseNewArgs(struct MacroArgs *args);
 void macro_FreeArgs(struct MacroArgs *args);
 char const *macro_GetArg(uint32_t i);

include/asm/warning.h

@@ -19,7 +19,6 @@ enum WarningID {
 	WARNING_CHARMAP_REDEF,        /* Charmap entry re-definition */
 	WARNING_DIV,		      /* Division undefined behavior */
 	WARNING_EMPTY_DATA_DIRECTIVE, /* `db`, `dw` or `dl` directive without data in ROM */
-	WARNING_EMPTY_ENTRY,	      /* Empty entry in `db`, `dw` or `dl` */
 	WARNING_EMPTY_MACRO_ARG,      /* Empty macro argument */
 	WARNING_EMPTY_STRRPL,	      /* Empty second argument in `STRRPL` */
 	WARNING_LARGE_CONSTANT,	      /* Constants too large */

src/asm/lexer.c

@@ -360,7 +360,6 @@ struct LexerState {
 	bool disableMacroArgs;
 	bool disableInterpolation;
 	size_t macroArgScanDistance; /* Max distance already scanned for macro args */
-	bool injectNewline; /* Whether to inject a newline at EOF */
 	bool expandStrings;
 	struct Expansion *expansions;
 	size_t expansionOfs; /* Offset into the current top-level expansion (negative = before) */
@@ -382,7 +381,6 @@ static void initState(struct LexerState *state)
 	state->disableMacroArgs = false;
 	state->disableInterpolation = false;
 	state->macroArgScanDistance = 0;
-	state->injectNewline = false;
 	state->expandStrings = true;
 	state->expansions = NULL;
 	state->expansionOfs = 0;
@@ -640,11 +638,6 @@ void lexer_SetMode(enum LexerMode mode)
 	lexerState->mode = mode;
 }
 
-bool lexer_IsRawMode(void)
-{
-	return lexerState->mode == LEXER_RAW;
-}
-
 void lexer_ToggleStringExpansion(bool enable)
 {
 	lexerState->expandStrings = enable;
@@ -2054,10 +2047,6 @@ static int yylex_NORMAL(void)
 			return T_NEWLINE;
 
 		case EOF:
-			if (lexerState->injectNewline) {
-				lexerState->injectNewline = false;
-				return T_NEWLINE;
-			}
 			return T_EOF;
 
 		/* Handle escapes */
@@ -2129,13 +2118,14 @@ static int yylex_RAW(void)
 
 	/* This is essentially a modified `appendStringLiteral` */
 	size_t i = 0;
+	int c;
 
 	/* Trim left whitespace (stops at a block comment or line continuation) */
 	while (isWhitespace(peek(0)))
 		shiftChars(1);
 
 	for (;;) {
-		int c = peek(0);
+		c = peek(0);
 
 		switch (c) {
 		case '"': /* String literals inside macro args */
@@ -2151,29 +2141,7 @@ static int yylex_RAW(void)
 		case '\r':
 		case '\n':
 		case EOF:
-			// Returning T_COMMAs to the parser would mean that two consecutive commas
-			// (i.e. an empty argument) need to return two different tokens (T_STRING
-			// then T_COMMA) without advancing the read. To avoid this, commas in raw
-			// mode end the current macro argument but are not tokenized themselves.
-			if (c == ',')
-				shiftChars(1);
-			else
-				lexer_SetMode(LEXER_NORMAL);
-			// If a macro is invoked on the last line of a file, with no blank
-			// line afterwards, returning EOF afterwards will cause Bison to
-			// stop parsing, despite the lexer being ready to output more.
-			if (c == EOF)
-				lexerState->injectNewline = true;
-			/* Trim right whitespace */
-			while (i && isWhitespace(yylval.tzString[i - 1]))
-				i--;
-			if (i == sizeof(yylval.tzString)) {
-				i--;
-				warning(WARNING_LONG_STR, "Macro argument too long\n");
-			}
-			yylval.tzString[i] = '\0';
-			dbgPrint("Read raw string \"%s\"\n", yylval.tzString);
-			return T_STRING;
+			goto finish;
 
 		case '/': /* Block comments inside macro args */
 			shiftChars(1); /* Shift the slash */
@@ -2235,6 +2203,49 @@ static int yylex_RAW(void)
 			break;
 		}
 	}
+
+finish:
+	if (i == sizeof(yylval.tzString)) {
+		i--;
+		warning(WARNING_LONG_STR, "Macro argument too long\n");
+	}
+	/* Trim right whitespace */
+	while (i && isWhitespace(yylval.tzString[i - 1]))
+		i--;
+	yylval.tzString[i] = '\0';
+
+	dbgPrint("Read raw string \"%s\"\n", yylval.tzString);
+
+	// Returning T_COMMAs to the parser would mean that two consecutive commas
+	// (i.e. an empty argument) need to return two different tokens (T_STRING
+	// then T_COMMA) without advancing the read. To avoid this, commas in raw
+	// mode end the current macro argument but are not tokenized themselves.
+	if (c == ',') {
+		shiftChars(1);
+		return T_STRING;
+	}
+
+	// The last argument may end in a trailing comma, newline, or EOF.
+	// To allow trailing commas, raw mode will continue after the last
+	// argument, immediately lexing the newline or EOF again (i.e. with
+	// an empty raw string before it). This will not be treated as a
+	// macro argument. To pass an empty last argument, use a second
+	// trailing comma.
+	if (i > 0)
+		return T_STRING;
+	lexer_SetMode(LEXER_NORMAL);
+
+	// If a macro is invoked on the last line of a file, with no blank
+	// line afterwards, returning EOF afterwards will cause Bison to
+	// stop parsing, despite the lexer being ready to output more.
+	// To avoid this, return T_NEWLINE for EOF as well.
+	if (c == '\r' || c == '\n') {
+		shiftChars(1);
+		/* Handle CRLF */
+		if (c == '\r' && peek(0) == '\n')
+			shiftChars(1);
+	}
+	return T_NEWLINE;
 }
 
 #undef append_yylval_tzString

src/asm/macro.c

@@ -59,15 +59,11 @@ struct MacroArgs *macro_NewArgs(void)
 	return args;
 }
 
-void macro_AppendArg(struct MacroArgs **argPtr, char *s, bool isLastArg)
+void macro_AppendArg(struct MacroArgs **argPtr, char *s)
 {
 #define macArgs (*argPtr)
-	if (s[0] == '\0') {
-		/* Zero arguments are parsed as a spurious empty argument; do not append it */
-		if (isLastArg && !macArgs->nbArgs)
-			return;
+	if (s[0] == '\0')
 		warning(WARNING_EMPTY_MACRO_ARG, "Empty macro argument\n");
-	}
 	if (macArgs->nbArgs == MAXMACROARGS)
 		error("A maximum of " EXPAND_AND_STR(MAXMACROARGS) " arguments is allowed\n");
 	if (macArgs->nbArgs >= macArgs->capacity) {
@@ -113,27 +109,26 @@ char *macro_GetAllArgs(void)
 	if (macroArgs->shift >= macroArgs->nbArgs)
 		return "";
 
-	size_t len = strlen(macroArgs->args[macroArgs->shift]);
+	size_t len = 0;
 
-	for (uint32_t i = macroArgs->shift + 1; i < macroArgs->nbArgs; i++)
-		len += 1 + strlen(macroArgs->args[i]);
+	for (uint32_t i = macroArgs->shift; i < macroArgs->nbArgs; i++)
+		len += strlen(macroArgs->args[i]) + 1; /* 1 for comma */
 
-	char *str = malloc(len + 1);
+	char *str = malloc(len + 1); /* 1 for '\0' */
+	char *ptr = str;
 
 	if (!str)
 		fatalerror("Failed to allocate memory for expanding '\\#': %s\n", strerror(errno));
 
-	char *ptr = str;
+	for (uint32_t i = macroArgs->shift; i < macroArgs->nbArgs; i++) {
+		size_t n = strlen(macroArgs->args[i]);
 
-	size_t n = strlen(macroArgs->args[macroArgs->shift]);
-
-	memcpy(ptr, macroArgs->args[macroArgs->shift], n);
-	ptr += n;
-	for (uint32_t i = macroArgs->shift + 1; i < macroArgs->nbArgs; i++) {
-		*ptr++ = ','; /* no space after comma */
-		n = strlen(macroArgs->args[i]);
 		memcpy(ptr, macroArgs->args[i], n);
 		ptr += n;
+
+		/* Commas go between args and after a last empty arg */
+		if (i < macroArgs->nbArgs - 1 || n == 0)
+			*ptr++ = ','; /* no space after comma */
 	}
 	*ptr = '\0';
 

src/asm/parser.y

@@ -430,7 +430,6 @@ enum {
 		int32_t step;
 	} forArgs;
 	struct StrFmtArgList strfmtArgs;
-	bool hasEmpty; // Whether `db`, `dw`, `dl` argument lists contain any empty entries
 }
 
 %type	<sVal>		relocexpr
@@ -445,9 +444,6 @@ enum {
 %type	<sVal>		reloc_16bit
 %type	<sVal>		reloc_16bit_no_str
 %type	<nConstValue>	sectiontype
-%type	<hasEmpty>	constlist_8bit  constlist_8bit_entry
-%type	<hasEmpty>	constlist_16bit constlist_16bit_entry
-%type	<hasEmpty>	constlist_32bit constlist_32bit_entry
 
 %type	<tzString>	string
 %type	<tzString>	strcat_args
@@ -728,6 +724,7 @@ label		: %empty
 ;
 
 macro		: T_ID {
+			// Parsing 'macroargs' will restore the lexer's normal mode
 			lexer_SetMode(LEXER_RAW);
 		} macroargs {
 			fstk_RunMacro($1, $3);
@@ -738,7 +735,7 @@ macroargs	: %empty {
 			$$ = macro_NewArgs();
 		}
 		| macroargs T_STRING {
-			macro_AppendArg(&($$), strdup($2), !lexer_IsRawMode());
+			macro_AppendArg(&($$), strdup($2));
 		}
 ;
 
@@ -791,6 +788,9 @@ directive	: include
 		| align
 ;
 
+trailing_comma	: %empty | T_COMMA
+;
+
 align		: T_OP_ALIGN uconst {
 			if ($2 > 16)
 				error("Alignment must be between 0 and 16, not %u\n", $2);
@@ -809,14 +809,13 @@ align		: T_OP_ALIGN uconst {
 ;
 
 opt		: T_POP_OPT {
+			// Parsing 'opt_list' will restore the lexer's normal mode
 			lexer_SetMode(LEXER_RAW);
-		} opt_list {
-			lexer_SetMode(LEXER_NORMAL);
-		}
+		} opt_list
 ;
 
 opt_list	: opt_list_entry
-		| opt_list T_COMMA opt_list_entry
+		| opt_list opt_list_entry
 ;
 
 opt_list_entry	: T_STRING		{ opt_Parse($1); }
@@ -984,7 +983,7 @@ endu		: T_POP_ENDU	{ sect_EndUnion(); }
 ;
 
 ds		: T_POP_DS uconst	{ out_Skip($2, true); }
-		| T_POP_DS uconst T_COMMA ds_args {
+		| T_POP_DS uconst T_COMMA ds_args trailing_comma {
 			out_RelBytes($2, $4.args, $4.nbArgs);
 			freeDsArgList(&$4);
 		}
@@ -1004,34 +1003,21 @@ ds_args		: reloc_8bit {
 		}
 ;
 
-/* Authorize empty entries if there is only one */
-db		: T_POP_DB constlist_8bit_entry T_COMMA constlist_8bit {
-			if ($2 || $4)
-				warning(WARNING_EMPTY_ENTRY,
-					"Empty entry in list of 8-bit elements (treated as padding).\n");
-		}
-		| T_POP_DB constlist_8bit_entry
+db		: T_POP_DB	{ out_Skip(1, false); }
+		| T_POP_DB constlist_8bit trailing_comma
 ;
 
-dw		: T_POP_DW constlist_16bit_entry T_COMMA constlist_16bit {
-			if ($2 || $4)
-				warning(WARNING_EMPTY_ENTRY,
-					"Empty entry in list of 16-bit elements (treated as padding).\n");
-		}
-		| T_POP_DW constlist_16bit_entry
+dw		: T_POP_DW	{ out_Skip(2, false); }
+		| T_POP_DW constlist_16bit trailing_comma
 ;
 
-dl		: T_POP_DL constlist_32bit_entry T_COMMA constlist_32bit {
-			if ($2 || $4)
-				warning(WARNING_EMPTY_ENTRY,
-					"Empty entry in list of 32-bit elements (treated as padding).\n");
-		}
-		| T_POP_DL constlist_32bit_entry
+dl		: T_POP_DL	{ out_Skip(4, false); }
+		| T_POP_DL constlist_32bit trailing_comma
 ;
 
 purge		: T_POP_PURGE {
 			lexer_ToggleStringExpansion(false);
-		} purge_list {
+		} purge_list trailing_comma {
 			lexer_ToggleStringExpansion(true);
 		}
 ;
@@ -1052,7 +1038,7 @@ purge_list	: purge_list_entry
 purge_list_entry : scoped_id	{ sym_Purge($1); }
 ;
 
-export		: T_POP_EXPORT export_list
+export		: T_POP_EXPORT export_list trailing_comma
 ;
 
 export_list	: export_list_entry
@@ -1113,11 +1099,11 @@ pushc		: T_POP_PUSHC	{ charmap_Push(); }
 popc		: T_POP_POPC	{ charmap_Pop(); }
 ;
 
-print		: T_POP_PRINT print_exprs
+print		: T_POP_PRINT print_exprs trailing_comma
 ;
 
 println		: T_POP_PRINTLN { putchar('\n'); }
-		| T_POP_PRINTLN print_exprs { putchar('\n'); }
+		| T_POP_PRINTLN print_exprs trailing_comma { putchar('\n'); }
 ;
 
 print_exprs	: print_expr
@@ -1165,18 +1151,11 @@ const_3bit	: const {
 ;
 
 constlist_8bit	: constlist_8bit_entry
-		| constlist_8bit T_COMMA constlist_8bit_entry {
-			$$ = $1 || $3;
-		}
+		| constlist_8bit T_COMMA constlist_8bit_entry
 ;
 
-constlist_8bit_entry : %empty {
-			out_Skip(1, false);
-			$$ = true;
-		}
-		| reloc_8bit_no_str	{
+constlist_8bit_entry : reloc_8bit_no_str	{
 			out_RelByte(&$1, 0);
-			$$ = false;
 		}
 		| string {
 			uint8_t *output = malloc(strlen($1)); /* Cannot be larger than that */
@@ -1184,23 +1163,15 @@ constlist_8bit_entry : %empty {
 
 			out_AbsByteGroup(output, length);
 			free(output);
-			$$ = false;
 		}
 ;
 
 constlist_16bit : constlist_16bit_entry
-		| constlist_16bit T_COMMA constlist_16bit_entry {
-			$$ = $1 || $3;
-		}
+		| constlist_16bit T_COMMA constlist_16bit_entry
 ;
 
-constlist_16bit_entry : %empty {
-			out_Skip(2, false);
-			$$ = true;
-		}
-		| reloc_16bit_no_str	{
+constlist_16bit_entry : reloc_16bit_no_str	{
 			out_RelWord(&$1, 0);
-			$$ = false;
 		}
 		| string {
 			uint8_t *output = malloc(strlen($1)); /* Cannot be larger than that */
@@ -1208,23 +1179,15 @@ constlist_16bit_entry : %empty {
 
 			out_AbsWordGroup(output, length);
 			free(output);
-			$$ = false;
 		}
 ;
 
 constlist_32bit : constlist_32bit_entry
-		| constlist_32bit T_COMMA constlist_32bit_entry {
-			$$ = $1 || $3;
-		}
+		| constlist_32bit T_COMMA constlist_32bit_entry
 ;
 
-constlist_32bit_entry : %empty {
-			out_Skip(4, false);
-			$$ = true;
-		}
-		| relocexpr_no_str	{
+constlist_32bit_entry :relocexpr_no_str	{
 			out_RelLong(&$1, 0);
-			$$ = false;
 		}
 		| string {
 			uint8_t *output = malloc(strlen($1)); /* Cannot be larger than that */
@@ -1232,7 +1195,6 @@ constlist_32bit_entry : %empty {
 
 			out_AbsLongGroup(output, length);
 			free(output);
-			$$ = false;
 		}
 ;
 

src/asm/rgbasm.1

@@ -179,9 +179,9 @@ Enables literally every warning.
 .Pp
 The following warnings are actual warning flags; with each description, the corresponding warning flag is included.
 Note that each of these flag also has a negation (for example,
-.Fl Wempty-entry
+.Fl Wcharmap-redef
 enables the warning that
-.Fl Wno-empty-entry
+.Fl Wno-charmap-redef
 disables).
 Only the non-default flag is listed here.
 Ignoring the
@@ -209,12 +209,6 @@ This warning is enabled by
 .Fl Wall .
 .It Fl Wdiv
 Warn when dividing the smallest negative integer by -1, which yields itself due to integer overflow.
-.It Fl Wempty-entry
-Warn when an empty entry is encountered in a
-.Ic db , dw , dl
-list.
-This warning is enabled by
-.Fl Wextra .
 .It Fl Wempty-macro-arg
 Warn when a macro argument is empty.
 This warning is enabled by

src/asm/rgbasm.5

@@ -1282,7 +1282,7 @@ You can also use
 .Ic DB , DW
 and
 .Ic DL
-without arguments, or leaving empty elements at any point in the list.
+without arguments.
 This works exactly like
 .Ic DS 1 , DS 2
 and

src/asm/warning.c

@@ -34,7 +34,6 @@ static enum WarningState const defaultWarnings[NB_WARNINGS] = {
 	[WARNING_CHARMAP_REDEF]		= WARNING_DISABLED,
 	[WARNING_DIV]			= WARNING_DISABLED,
 	[WARNING_EMPTY_DATA_DIRECTIVE]	= WARNING_DISABLED,
-	[WARNING_EMPTY_ENTRY]		= WARNING_DISABLED,
 	[WARNING_EMPTY_MACRO_ARG]	= WARNING_DISABLED,
 	[WARNING_EMPTY_STRRPL]		= WARNING_DISABLED,
 	[WARNING_LARGE_CONSTANT]	= WARNING_DISABLED,
@@ -77,7 +76,6 @@ static char const *warningFlags[NB_WARNINGS_ALL] = {
 	"charmap-redef",
 	"div",
 	"empty-data-directive",
-	"empty-entry",
 	"empty-macro-arg",
 	"empty-strrpl",
 	"large-constant",
@@ -113,7 +111,6 @@ static uint8_t const _wallCommands[] = {
 
 /* Warnings that are less likely to indicate an error */
 static uint8_t const _wextraCommands[] = {
-	WARNING_EMPTY_ENTRY,
 	WARNING_EMPTY_MACRO_ARG,
 	WARNING_MACRO_SHIFT,
 	WARNING_NESTED_COMMENT,
@@ -125,7 +122,6 @@ static uint8_t const _weverythingCommands[] = {
 	WARNING_BUILTIN_ARG,
 	WARNING_DIV,
 	WARNING_EMPTY_DATA_DIRECTIVE,
-	WARNING_EMPTY_ENTRY,
 	WARNING_EMPTY_MACRO_ARG,
 	WARNING_EMPTY_STRRPL,
 	WARNING_LARGE_CONSTANT,

test/asm/macro-arguments.asm

@@ -9,15 +9,20 @@ ENDM
 
 	mac /* block
 		...comment */ ; comment
-	mac /*a*/ 1 , 2 /*b*/
+	mac /*a*/ 1 , 2 /*b*/ , ; trailing comma
 	mac \
 	c, d
 	mac 1, 2 + /* another ;
 		; comment */ 2, 3
 
+	mac           a                                                                                                                                                                                                                                                               b           ; truncated
+
 	mac
+	mac ,
+	mac a,
 	mac a,,
 	mac ,,z
 	mac a,,z
 	mac ,a,b,c,
-	mac ,,x,,
+	mac ,,x,,,
+	mac E,O,F ; no newline

test/asm/macro-arguments.err

@@ -1,22 +1,22 @@
-warning: macro-arguments.asm(19): [-Wempty-macro-arg]
-    Empty macro argument
-warning: macro-arguments.asm(19): [-Wempty-macro-arg]
-    Empty macro argument
-warning: macro-arguments.asm(20): [-Wempty-macro-arg]
-    Empty macro argument
-warning: macro-arguments.asm(20): [-Wempty-macro-arg]
-    Empty macro argument
+warning: macro-arguments.asm(18): [-Wlong-string]
+    Macro argument too long
 warning: macro-arguments.asm(21): [-Wempty-macro-arg]
     Empty macro argument
-warning: macro-arguments.asm(22): [-Wempty-macro-arg]
-    Empty macro argument
-warning: macro-arguments.asm(22): [-Wempty-macro-arg]
-    Empty macro argument
 warning: macro-arguments.asm(23): [-Wempty-macro-arg]
     Empty macro argument
-warning: macro-arguments.asm(23): [-Wempty-macro-arg]
+warning: macro-arguments.asm(24): [-Wempty-macro-arg]
     Empty macro argument
-warning: macro-arguments.asm(23): [-Wempty-macro-arg]
+warning: macro-arguments.asm(24): [-Wempty-macro-arg]
     Empty macro argument
-warning: macro-arguments.asm(23): [-Wempty-macro-arg]
+warning: macro-arguments.asm(25): [-Wempty-macro-arg]
+    Empty macro argument
+warning: macro-arguments.asm(26): [-Wempty-macro-arg]
+    Empty macro argument
+warning: macro-arguments.asm(27): [-Wempty-macro-arg]
+    Empty macro argument
+warning: macro-arguments.asm(27): [-Wempty-macro-arg]
+    Empty macro argument
+warning: macro-arguments.asm(27): [-Wempty-macro-arg]
+    Empty macro argument
+warning: macro-arguments.asm(27): [-Wempty-macro-arg]
     Empty macro argument

test/asm/macro-arguments.out

@@ -13,12 +13,20 @@
 \2: <2 +  2>
 \3: <3>
 
+'mac a':
+\1: <a>
+
 'mac ':
 
+'mac ,':
+\1: <>
+
+'mac a':
+\1: <a>
+
 'mac a,,':
 \1: <a>
 \2: <>
-\3: <>
 
 'mac ,,z':
 \1: <>
@@ -30,17 +38,21 @@
 \2: <>
 \3: <z>
 
-'mac ,a,b,c,':
+'mac ,a,b,c':
 \1: <>
 \2: <a>
 \3: <b>
 \4: <c>
-\5: <>
 
-'mac ,,x,,':
+'mac ,,x,,,':
 \1: <>
 \2: <>
 \3: <x>
 \4: <>
 \5: <>
 
+'mac E,O,F':
+\1: <E>
+\2: <O>
+\3: <F>
+

test/asm/trailing-commas.asm

@@ -0,0 +1,25 @@
+SECTION "test", ROM0
+
+mac: MACRO
+	println "\#"
+ENDM
+
+	mac 1,2, 3 , ,5,
+
+	db 1,2,3,
+	dw 4,5,6,
+	dl 7,8,9,
+	ds 10, $a, $b, $c,
+
+	print "Hello", " ",
+	println "world", "!",
+
+spam:
+eggs:
+lobsterThermidor:
+
+	export spam, eggs,
+	purge lobsterThermidor,
+
+	opt boO, g.xX#,
+	dw %ooOOOOoo, `XX##..xx,

test/asm/trailing-commas.err

@@ -0,0 +1,2 @@
+warning: trailing-commas.asm(7): [-Wempty-macro-arg]
+    Empty macro argument

test/asm/trailing-commas.out

@@ -0,0 +1,2 @@
+1,2,3,,5
+Hello world!