diff --git a/src/evalvars.c b/src/evalvars.c
index f59dde9..bff6086 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -3293,6 +3293,24 @@
 }
 
 /*
+ * Set option "varname" to the value of "varp" for the current buffer/window.
+ */
+    static void
+set_option_from_tv(char_u *varname, typval_T *varp)
+{
+    long	numval = 0;
+    char_u	*strval;
+    char_u	nbuf[NUMBUFLEN];
+    int		error = FALSE;
+
+    if (!in_vim9script() || varp->v_type != VAR_STRING)
+	numval = (long)tv_get_number_chk(varp, &error);
+    strval = tv_get_string_buf_chk(varp, nbuf);
+    if (!error && strval != NULL)
+	set_option_value(varname, numval, strval, OPT_LOCAL);
+}
+
+/*
  * "setwinvar()" and "settabwinvar()" functions
  */
     static void
@@ -3304,7 +3322,6 @@
     int		need_switch_win;
     char_u	*varname, *winvarname;
     typval_T	*varp;
-    char_u	nbuf[NUMBUFLEN];
     tabpage_T	*tp = NULL;
 
     if (check_secure())
@@ -3325,17 +3342,7 @@
 	       || switch_win(&save_curwin, &save_curtab, win, tp, TRUE) == OK)
 	{
 	    if (*varname == '&')
-	    {
-		long	numval;
-		char_u	*strval;
-		int		error = FALSE;
-
-		++varname;
-		numval = (long)tv_get_number_chk(varp, &error);
-		strval = tv_get_string_buf_chk(varp, nbuf);
-		if (!error && strval != NULL)
-		    set_option_value(varname, numval, strval, OPT_LOCAL);
-	    }
+		set_option_from_tv(varname + 1, varp);
 	    else
 	    {
 		winvarname = alloc(STRLEN(varname) + 3);
@@ -3759,7 +3766,6 @@
     buf_T	*buf;
     char_u	*varname, *bufvarname;
     typval_T	*varp;
-    char_u	nbuf[NUMBUFLEN];
 
     if (check_secure())
 	return;
@@ -3772,19 +3778,12 @@
     {
 	if (*varname == '&')
 	{
-	    long	numval;
-	    char_u	*strval;
-	    int		error = FALSE;
 	    aco_save_T	aco;
 
 	    // set curbuf to be our buf, temporarily
 	    aucmd_prepbuf(&aco, buf);
 
-	    ++varname;
-	    numval = (long)tv_get_number_chk(varp, &error);
-	    strval = tv_get_string_buf_chk(varp, nbuf);
-	    if (!error && strval != NULL)
-		set_option_value(varname, numval, strval, OPT_LOCAL);
+	    set_option_from_tv(varname + 1, varp);
 
 	    // reset notion of buffer
 	    aucmd_restbuf(&aco);