diff --git a/qse/cmd/sed/sed.c b/qse/cmd/sed/sed.c
index 975f6695..20ac8983 100644
--- a/qse/cmd/sed/sed.c
+++ b/qse/cmd/sed/sed.c
@@ -139,6 +139,7 @@ static void print_usage (QSE_FILE* out, int argc, qse_char_t* argv[])
 	qse_fprintf (out, QSE_T(" -n        disable auto-print\n"));
 	qse_fprintf (out, QSE_T(" -f file   specify a script file\n"));
 	qse_fprintf (out, QSE_T(" -r        use the extended regular expression\n"));
+	qse_fprintf (out, QSE_T(" -R        enable non-standard extensions to the regular expression\n"));
 	qse_fprintf (out, QSE_T(" -a        perform strict address check\n"));
 	qse_fprintf (out, QSE_T(" -w        allow address format of start~step\n"));
 	qse_fprintf (out, QSE_T(" -x        allow text on the same line as c, a, i\n"));
@@ -150,7 +151,7 @@ static int handle_args (int argc, qse_char_t* argv[])
 {
 	static qse_opt_t opt = 
 	{
-		QSE_T("hnf:rawxym:"),
+		QSE_T("hnf:rRawxym:"),
 		QSE_NULL
 	};
 	qse_cint_t c;
@@ -195,6 +196,10 @@ static int handle_args (int argc, qse_char_t* argv[])
 				g_option |= QSE_SED_EXTENDEDREX;
 				break;
 
+			case QSE_T('R'):
+				g_option |= QSE_SED_NONSTDEXTREX;
+				break;
+
 			case QSE_T('a'):
 				g_option |= QSE_SED_STRICT;
 				break;
diff --git a/qse/include/qse/cmn/tre.h b/qse/include/qse/cmn/tre.h
index b03101ea..914bef45 100644
--- a/qse/include/qse/cmn/tre.h
+++ b/qse/include/qse/cmn/tre.h
@@ -72,7 +72,14 @@ enum qse_tre_cflag_t
 	QSE_TRE_NOSUBREG    = (1 << 3),
 	QSE_TRE_LITERAL     = (1 << 4),
 	QSE_TRE_RIGHTASSOC  = (1 << 5),
-	QSE_TRE_UNGREEDY    = (1 << 6)
+	QSE_TRE_UNGREEDY    = (1 << 6),
+
+	/* Enable non-standard extensions:
+	 *  - Enable (?:text) for no submatch backreference.
+	 *  - Enable perl-like (?...) extensions like (?i) 
+	 *    if QSE_TRE_EXTENDED is also set.
+	 */
+	QSE_TRE_NONSTDEXT   = (1 << 7) 
 };
 
 enum qse_tre_eflag_t
diff --git a/qse/include/qse/sed/sed.h b/qse/include/qse/sed/sed.h
index 5af6a2d5..75d67e47 100644
--- a/qse/include/qse/sed/sed.h
+++ b/qse/include/qse/sed/sed.h
@@ -1,5 +1,5 @@
 /*
- * $Id: sed.h 562 2011-09-07 15:36:08Z hyunghwan.chung $
+ * $Id: sed.h 563 2011-09-08 07:49:53Z hyunghwan.chung $
  *
     Copyright 2006-2011 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -133,14 +133,15 @@ typedef const qse_char_t* (*qse_sed_errstr_t) (
  */
 enum qse_sed_option_t
 {
-	QSE_SED_STRIPLS     = (1 << 0), /**< strip leading spaces from text */
-	QSE_SED_KEEPTBS     = (1 << 1), /**< keep an trailing backslash */
-	QSE_SED_ENSURENL    = (1 << 2), /**< ensure NL at the text end */
-	QSE_SED_QUIET       = (1 << 3), /**< do not print pattern space */
-	QSE_SED_STRICT      = (1 << 4), /**< do strict address check */
-	QSE_SED_STARTSTEP   = (1 << 5), /**< allow start~step */
-	QSE_SED_EXTENDEDREX = (1 << 6), /**< allow {n,m} in regular expression */
-	QSE_SED_SAMELINE    = (1 << 7), /**< allow text on the same line as c, a, i */
+	QSE_SED_STRIPLS      = (1 << 0), /**< strip leading spaces from text */
+	QSE_SED_KEEPTBS      = (1 << 1), /**< keep an trailing backslash */
+	QSE_SED_ENSURENL     = (1 << 2), /**< ensure NL at the text end */
+	QSE_SED_QUIET        = (1 << 3), /**< do not print pattern space */
+	QSE_SED_STRICT       = (1 << 4), /**< do strict address check */
+	QSE_SED_STARTSTEP    = (1 << 5), /**< allow start~step */
+	QSE_SED_EXTENDEDREX  = (1 << 6), /**< use extended regex */
+	QSE_SED_NONSTDEXTREX = (1 << 7), /**< enable non-standard extensions to regex */
+	QSE_SED_SAMELINE     = (1 << 8), /**< allow text on the same line as c, a, i */
 };
 typedef enum qse_sed_option_t qse_sed_option_t;
 
diff --git a/qse/lib/cmn/tre-parse.c b/qse/lib/cmn/tre-parse.c
index 1893f73a..dcfd0148 100644
--- a/qse/lib/cmn/tre-parse.c
+++ b/qse/lib/cmn/tre-parse.c
@@ -1084,6 +1084,9 @@ tre_parse(tre_parse_ctx_t *ctx)
 				break;
 			/*FALLTHROUGH*/
 		case CHAR_STAR:
+/* QSE - added this label */
+parse_star:
+/* END QSE */
 		{
 			tre_ast_node_t *tmp_node;
 			int minimal = (ctx->cflags & REG_UNGREEDY) ? 1 : 0;
@@ -1093,9 +1096,9 @@ tre_parse(tre_parse_ctx_t *ctx)
 			const tre_char_t *tmp_re;
 #endif
 
-			if (*ctx->re == CHAR_PLUS)
+			if (*ctx->re == CHAR_PLUS) /* QSE: case CHAR_PLUS fell through down here */
 				rep_min = 1;
-			if (*ctx->re == CHAR_QUESTIONMARK)
+			if (*ctx->re == CHAR_QUESTIONMARK) /* QSE: case CHAR_QUESTIONMARK fell though down here */
 				rep_max = 1;
 #ifdef TRE_DEBUG
 			tmp_re = ctx->re;
@@ -1103,7 +1106,7 @@ tre_parse(tre_parse_ctx_t *ctx)
 
 			if (ctx->re + 1 < ctx->re_end)
 			{
-				if (*(ctx->re + 1) == CHAR_QUESTIONMARK)
+				if (*(ctx->re + 1) == CHAR_QUESTIONMARK) /* QSE: +?, ??, *? */
 				{
 					minimal = !(ctx->cflags & REG_UNGREEDY);
 					ctx->re++;
@@ -1136,6 +1139,8 @@ tre_parse(tre_parse_ctx_t *ctx)
 
 		case CHAR_BACKSLASH:
 			/* "\{" is special without REG_EXTENDED */
+			/* QSE  - also handle \+ and \? */
+			/*
 			if (!(ctx->cflags & REG_EXTENDED)
 			        && ctx->re + 1 < ctx->re_end
 			        && *(ctx->re + 1) == CHAR_LBRACE)
@@ -1145,6 +1150,24 @@ tre_parse(tre_parse_ctx_t *ctx)
 			}
 			else
 				break;
+			*/
+			if (!(ctx->cflags & REG_EXTENDED) && ctx->re + 1 < ctx->re_end)
+			{
+				if (*(ctx->re + 1) == CHAR_LBRACE) 
+				{
+					ctx->re++;
+					goto parse_brace;
+				}
+				else if (*(ctx->re + 1) == CHAR_PLUS || 
+				         *(ctx->re + 1) == CHAR_QUESTIONMARK) 
+				{
+					ctx->re++;
+					goto parse_star;
+				}
+			}
+			else break;
+			/* END QSE */
+
 
 		case CHAR_LBRACE:
 			/* "{" is literal without REG_EXTENDED */
@@ -1184,8 +1207,10 @@ parse_brace:
 
 			/* Handle "(?...)" extensions.  They work in a way similar
 			 to Perls corresponding extensions. */
-			if (ctx->cflags & REG_EXTENDED
-			        && *(ctx->re + 1) == CHAR_QUESTIONMARK)
+			/* QSE: added ctx->cflags & REG_NONSTDEXT */
+			if ((ctx->cflags & REG_NONSTDEXT) &&
+			    (ctx->cflags & REG_EXTENDED) && 
+			    *(ctx->re + 1) == CHAR_QUESTIONMARK)
 			{
 				int new_cflags = ctx->cflags;
 				int bit = 1;
@@ -1293,10 +1318,13 @@ parse_brace:
 			            && *(ctx->re - 1) == CHAR_BACKSLASH))
 			{
 				depth++;
-				if (ctx->re + 2 < ctx->re_end
-				        && *(ctx->re + 1) == CHAR_QUESTIONMARK
-				        && *(ctx->re + 2) == CHAR_COLON)
+				/* QSE: added ctx->cflags & REG_NONSTDEXT */
+				if ((ctx->cflags & REG_NONSTDEXT) &&
+				     ctx->re + 2 < ctx->re_end && 
+				     *(ctx->re + 1) == CHAR_QUESTIONMARK &&
+				     *(ctx->re + 2) == CHAR_COLON)
 				{
+					/* QSE: \(?: or (?: depending on REG_EXTENDED */
 					DPRINT(("tre_parse: group begin: '%.*" STRF
 					        "', no submatch\n", REST(ctx->re)));
 					/* Don't mark for submatching. */
diff --git a/qse/lib/cmn/tre.h b/qse/lib/cmn/tre.h
index 52b93823..332ff6b2 100644
--- a/qse/lib/cmn/tre.h
+++ b/qse/lib/cmn/tre.h
@@ -133,6 +133,7 @@ typedef qse_cint_t tre_cint_t;
 #define REG_LITERAL     QSE_TRE_LITERAL 
 #define REG_RIGHT_ASSOC QSE_TRE_RIGHTASSOC
 #define REG_UNGREEDY    QSE_TRE_UNGREEDY 
+#define REG_NONSTDEXT   QSE_TRE_NONSTDEXT
 
 /* POSIX tre_regexec() flags. */
 #define REG_NOTBOL QSE_TRE_NOTBOL
diff --git a/qse/lib/sed/sed.c b/qse/lib/sed/sed.c
index 46e9aae8..a93e84e1 100644
--- a/qse/lib/sed/sed.c
+++ b/qse/lib/sed/sed.c
@@ -1,5 +1,5 @@
 /*
- * $Id: sed.c 562 2011-09-07 15:36:08Z hyunghwan.chung $
+ * $Id: sed.c 563 2011-09-08 07:49:53Z hyunghwan.chung $
  *
     Copyright 2006-2011 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -198,6 +198,7 @@ static void* build_rex (
 	/* ignorecase is a compile option for TRE */
 	if (ignorecase) opt |= QSE_TRE_IGNORECASE; 
 	if (sed->option & QSE_SED_EXTENDEDREX) opt |= QSE_TRE_EXTENDED;
+	if (sed->option & QSE_SED_NONSTDEXTREX) opt |= QSE_TRE_NONSTDEXT;
 
 	if (qse_tre_compx (tre, str->ptr, str->len, QSE_NULL, opt) <= -1)
 	{
@@ -230,7 +231,7 @@ static int matchtre (
 	qse_cstr_t submat[9], const qse_sed_loc_t* loc)
 {
 	int n;
-	qse_tre_match_t match[10];
+	qse_tre_match_t match[10] = { { 0, 0 }, };
 
 	n = qse_tre_execx (tre, str->ptr, str->len, match, 10, opt);
 	if (n <= -1)
@@ -258,7 +259,7 @@ static int matchtre (
 
 		/* you must intialize submat before you pass into this 
 		 * function because it can abort filling */
-		for (i = 1; i <= 10; i++)
+		for (i = 1; i < QSE_COUNTOF(match); i++)
 		{
 			if (match[i].rm_so == -1) break;
 			submat[i-1].ptr = &str->ptr[match[i].rm_so];
@@ -569,6 +570,8 @@ static QSE_INLINE void* compile_rex_address (qse_sed_t* sed, qse_char_t rxend)
 {
 	if (pickup_rex (sed, rxend, 1, QSE_NULL, &sed->tmp.rex) <= -1) return QSE_NULL;
 /* TODO: support ignore case option for address */
+
+	if (QSE_STR_LEN(&sed->tmp.rex) <= 0) return EMPTY_REX;
 	return build_rex (sed, QSE_STR_CSTR(&sed->tmp.rex), 0, &sed->src.loc);
 }
 
@@ -592,11 +595,6 @@ static qse_sed_adr_t* get_address (qse_sed_t* sed, qse_sed_adr_t* a)
 		}
 		while ((c = CURSC(sed)) >= QSE_T('0') && c <= QSE_T('9'));
 
-#if 0
-		/* line number 0 is illegal */
-		if (lno == 0) return QSE_NULL;
-#endif
-
 		a->type = QSE_SED_ADR_LINE;
 		a->u.lno = lno;
 	}
@@ -985,8 +983,8 @@ static int get_subst (qse_sed_t* sed, qse_sed_cmd_t* cmd)
 
 	if (pickup_rex (sed, delim, 1, cmd, t[0]) <= -1) goto oops;
 	if (pickup_rex (sed, delim, 0, cmd, t[1]) <= -1) goto oops;
-
 #if 0
+/* calling pickup_rex twice above instead of commenting out this part */
 	for (i = 0; i < 2; i++)
 	{
 		c = NXTSC (sed);
@@ -2517,17 +2515,13 @@ static qse_sed_cmd_t* exec_cmd (qse_sed_t* sed, qse_sed_cmd_t* cmd)
 			break;
 			
 		case QSE_SED_CMD_QUIT:
-			if (!(sed->option && QSE_SED_QUIET))
-			{
-				n = write_str (sed, 
-					QSE_STR_PTR(&sed->e.in.line),
-					QSE_STR_LEN(&sed->e.in.line));
-				if (n <= -1) return QSE_NULL;
-			}
-		case QSE_SED_CMD_QUIT_QUIET:
 			jumpto = &sed->cmd.quit;
 			break;
 
+		case QSE_SED_CMD_QUIT_QUIET:
+			jumpto = &sed->cmd.quit_quiet;
+			break;
+
 		case QSE_SED_CMD_APPEND:
 			if (qse_lda_insert (
 				&sed->e.txt.appended,
@@ -3052,6 +3046,7 @@ int qse_sed_exec (qse_sed_t* sed, qse_sed_io_fun_t inf, qse_sed_io_fun_t outf)
 	while (1)
 	{
 		qse_size_t i;
+		int quit = 0;
 
 		n = read_line (sed, 0);
 		if (n <= -1) { ret = -1; goto done; }
@@ -3081,7 +3076,8 @@ int qse_sed_exec (qse_sed_t* sed, qse_sed_io_fun_t inf, qse_sed_io_fun_t outf)
 
 				j = exec_cmd (sed, c);
 				if (j == QSE_NULL) { ret = -1; goto done; }
-				if (j == &sed->cmd.quit) goto done;
+				if (j == &sed->cmd.quit_quiet) goto done;
+				if (j == &sed->cmd.quit) { quit = 1; break; }
 				if (j == &sed->cmd.again) goto again;
 
 				/* go to the next command */
@@ -3118,6 +3114,8 @@ int qse_sed_exec (qse_sed_t* sed, qse_sed_io_fun_t inf, qse_sed_io_fun_t outf)
 		 * in write functions */
 		n = flush (sed);
 		if (n <= -1) { ret = -1; goto done; }
+
+		if (quit) break;
 	}
 
 done:
diff --git a/qse/lib/sed/sed.h b/qse/lib/sed/sed.h
index 354abe30..814edfd9 100644
--- a/qse/lib/sed/sed.h
+++ b/qse/lib/sed/sed.h
@@ -1,5 +1,5 @@
 /*
- * $Id: sed.h 560 2011-09-06 14:18:36Z hyunghwan.chung $
+ * $Id: sed.h 563 2011-09-08 07:49:53Z hyunghwan.chung $
  *
     Copyright 2006-2011 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -215,6 +215,7 @@ struct qse_sed_t
 		qse_sed_cmd_blk_t* lb; /**< points to the last block */
 
 		qse_sed_cmd_t      quit; 
+		qse_sed_cmd_t      quit_quiet; 
 		qse_sed_cmd_t      again;
 		qse_sed_cmd_t      over;
 	} cmd;