10547: (#s) and (#e) pattern assertions

2 files changed, 701 insertions, 242 deletions

diff --git a/Src/pattern.c b/Src/pattern.c
index d70c5c1d9..1c90f72a1 100644
--- a/Src/pattern.c
+++ b/Src/pattern.c
@@ -83,6 +83,8 @@ typedef union upat *Upat;
 #define	P_ONEHASH 0x06	/* node	Match this (simple) thing 0 or more times. */
 #define	P_TWOHASH 0x07	/* node	Match this (simple) thing 1 or more times. */
 #define P_GFLAGS  0x08	/* long Match nothing and set globbing flags */
+#define P_ISSTART 0x09  /* no   Match start of string. */
+#define P_ISEND   0x0a  /* no   Match end of string. */
 /* numbered so we can test bit 5 for a branch */
 #define	P_BRANCH  0x20	/* node	Match this alternative, or the next... */
 #define	P_WBRANCH 0x21	/* uc* node P_BRANCH, but match at least 1 char */
@@ -645,34 +647,44 @@ patcompbranch(int *flagp)
 	    /* Globbing flags. */
 	    char *pp1 = patparse;
 	    int oldglobflags = patglobflags;
+	    long assert;
 	    patparse += (*patparse == '@') ? 3 : 2;
-	    if (!patgetglobflags(&patparse))
-		return 0;	    
-	    if (pp1 == patstart) {
-		/* Right at start of pattern, the simplest case.
-		 * Put them into the flags and don't emit anything.
-		 */
-		((Patprog)patout)->globflags = patglobflags;
-		continue;
-	    } else if (!*patparse) {
-		/* Right at the end, so just leave the flags for
-		 * the next Patprog in the chain to pick up.
+	    if (!patgetglobflags(&patparse, &assert))
+		return 0;
+	    if (assert) {
+		/*
+		 * Start/end assertion looking like flags, but
+		 * actually handled as a normal node
 		 */
-		break;
-	    }
-	    /*
-	     * Otherwise, we have to stick them in as a pattern
-	     * matching nothing.
-	     */
-	    if (oldglobflags != patglobflags) {
-		/* Flags changed */
-		union upat up;
-		latest = patnode(P_GFLAGS);
-		up.l = patglobflags;
-		patadd((char *)&up, 0, sizeof(union upat), 0);
+		latest = patnode(assert);
+		flags = 0;
 	    } else {
-		/* No effect. */
-		continue;
+		if (pp1 == patstart) {
+		    /* Right at start of pattern, the simplest case.
+		     * Put them into the flags and don't emit anything.
+		     */
+		    ((Patprog)patout)->globflags = patglobflags;
+		    continue;
+		} else if (!*patparse) {
+		    /* Right at the end, so just leave the flags for
+		     * the next Patprog in the chain to pick up.
+		     */
+		    break;
+		}
+		/*
+		 * Otherwise, we have to stick them in as a pattern
+		 * matching nothing.
+		 */
+		if (oldglobflags != patglobflags) {
+		    /* Flags changed */
+		    union upat up;
+		    latest = patnode(P_GFLAGS);
+		    up.l = patglobflags;
+		    patadd((char *)&up, 0, sizeof(union upat), 0);
+		} else {
+		    /* No effect. */
+		    continue;
+		}
 	    }
 	} else if (isset(EXTENDEDGLOB) && *patparse == Hat) {
 	    /*
@@ -707,10 +719,12 @@ patcompbranch(int *flagp)
 
 /**/
 int
-patgetglobflags(char **strp)
+patgetglobflags(char **strp, long *assertp)
 {
     char *nptr, *ptr = *strp;
     zlong ret;
+
+    *assertp = 0;
     /* (#X): assumes we are still positioned on the first X */
     for (; *ptr && *ptr != Outpar; ptr++) {
 	switch (*ptr) {
@@ -763,12 +777,23 @@ patgetglobflags(char **strp)
 	    patglobflags &= ~GF_MATCHREF;
 	    break;
 
+	case 's':
+	    *assertp = P_ISSTART;
+	    break;
+
+	case 'e':
+	    *assertp = P_ISEND;
+	    break;
+
 	default:
 	    return 0;
 	}
     }
     if (*ptr != Outpar)
 	return 0;
+    /* Start/end assertions must appear on their own. */
+    if (*assertp && (*strp)[1] != Outpar)
+	return 0;
     *strp = ptr + 1;
     return 1;
 }
@@ -1989,6 +2014,14 @@ patmatch(Upat prog)
 	     * anything here.
 	     */
 	    return 0;
+	case P_ISSTART:
+	    if (patinput != patinstart)
+		fail = 1;
+	    break;
+	case P_ISEND:
+	    if (*patinput)
+		fail = 1;
+	    break;
 	case P_END:
 	    if (!(fail = (*patinput && !(patflags & PAT_NOANCH))))
 		return 1;
@@ -2387,6 +2420,12 @@ patprop(Upat op)
     case P_GFLAGS:
 	p = "GFLAGS";
 	break;
+    case P_ISSTART:
+	p = "ISSTART";
+	break;
+    case P_ISEND:
+	p = "ISEND";
+	break;
     case P_NOTHING:
 	p = "NOTHING";
 	break;
diff --git a/Src/subst.c b/Src/subst.c
index 8f840d266..668d5eda3 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -42,27 +42,22 @@ char nulstring[] = {Nularg, '\0'};
  *  - Brace expansion
  *  - Tilde and equals substitution
  *
- * Bits 0 and 1 of flags are used in filesub.
- * bit 0 is set when we are doing MAGIC_EQUALSUBST or normal
- *	 assignment but not a typeset.
- * bit 1 is set on a real assignment (both typeset and normal).
- * bit 2 is a flag to paramsubst (single word sub)
+ * PF_* flags are defined in zsh.h
  */
 
 /**/
-void
+mod_export void
 prefork(LinkList list, int flags)
 {
     LinkNode node;
 
-    MUSTUSEHEAP("prefork");
     for (node = firstnode(list); node; incnode(node)) {
-	char *str, *str3;
+	char *str, c;
 
-	str = str3 = (char *)getdata(node);
-	if ((*str == Inang || *str == Outang || *str == Equals) &&
+	str = (char *)getdata(node);
+	if (((c = *str) == Inang || c == Outang || c == Equals) &&
 	    str[1] == Inpar) {
-	    if (*str == Inang || *str == Outang)
+	    if (c == Inang || c == Outang)
 		setdata(node, (void *) getproc(str));	/* <(...) or >(...) */
 	    else
 		setdata(node, (void *) getoutputfile(str));	/* =(...) */
@@ -70,20 +65,22 @@ prefork(LinkList list, int flags)
 		return;
 	} else {
 	    if (isset(SHFILEEXPANSION))
-		filesub((char **)getaddrdata(node), flags & 3);
-	    if (!(node = stringsubst(list, node, flags & 4)))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	    if (!(node = stringsubst(list, node, flags & PF_SINGLE)))
 		return;
 	}
     }
     for (node = firstnode(list); node; incnode(node)) {
 	if (*(char *)getdata(node)) {
 	    remnulargs(getdata(node));
-	    if (unset(IGNOREBRACES) && !(flags & 4))
+	    if (unset(IGNOREBRACES) && !(flags & PF_SINGLE))
 		while (hasbraces(getdata(node)))
 		    xpandbraces(list, &node);
 	    if (unset(SHFILEEXPANSION))
-		filesub((char **)getaddrdata(node), flags & 3);
-	} else if (!(flags & 4))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	} else if (!(flags & PF_SINGLE))
 	    uremnode(list, node);
 	if (errflag)
 	    return;
@@ -96,14 +93,16 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 {
     int qt;
     char *str3 = (char *)getdata(node);
-    char *str  = str3;
+    char *str  = str3, c;
 
-    while (!errflag && *str) {
-	if ((qt = *str == Qstring) || *str == String)
-	    if (str[1] == Inpar) {
+    while (!errflag && (c = *str)) {
+	if ((qt = c == Qstring) || c == String) {
+	    if ((c = str[1]) == Inpar) {
+		if (!qt)
+		    mult_isarr = 1;
 		str++;
 		goto comsub;
-	    } else if (str[1] == Inbrack) {
+	    } else if (c == Inbrack) {
 		/* $[...] */
 		char *str2 = str;
 		str2++;
@@ -115,7 +114,7 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 		str = arithsubst(str + 2, &str3, str2);
 		setdata(node, (void *) str3);
 		continue;
-	    } else if (str[1] == Snull) {
+	    } else if (c == Snull) {
 		str = getkeystring(str, NULL, 4, NULL);
 		continue;
 	    } else {
@@ -125,21 +124,25 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 		str3 = (char *)getdata(node);
 		continue;
 	    }
-	else if ((qt = *str == Qtick) || *str == Tick)
+	} else if ((qt = c == Qtick) || c == Tick)
 	  comsub: {
 	    LinkList pl;
 	    char *s, *str2 = str;
 	    char endchar;
 	    int l1, l2;
 
-	    if (*str == Inpar) {
+	    if (c == Inpar) {
 		endchar = Outpar;
 		str[-1] = '\0';
+#ifdef DEBUG
 		if (skipparens(Inpar, Outpar, &str))
-		    DPUTS(1, "BUG: parse error in command substitution");
+		    dputs("BUG: parse error in command substitution");
+#else
+		skipparens(Inpar, Outpar, &str);
+#endif
 		str--;
 	    } else {
-		endchar = *str;
+		endchar = c;
 		*str = '\0';
 
 		while (*++str != endchar)
@@ -148,7 +151,8 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 	    *str++ = '\0';
 	    if (endchar == Outpar && str2[1] == '(' && str[-2] == ')') {
 		/* Math substitution of the form $((...)) */
-		str = arithsubst(str2 + 1, &str3, str);
+		str[-2] = '\0';
+		str = arithsubst(str2 + 2, &str3, str);
 		setdata(node, (void *) str3);
 		continue;
 	    }
@@ -159,12 +163,12 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 	     * be left unchanged.  Note that the lexer doesn't tokenize   *
 	     * the body of a command substitution so if there are some    *
 	     * tokens here they are from a ${(e)~...} substitution.       */
-	    for (str = str2; *++str; )
-		if (itok(*str) && *str != Nularg &&
-		    !(endchar != Outpar && *str == Bnull &&
+	    for (str = str2; (c = *++str); )
+		if (itok(c) && c != Nularg &&
+		    !(endchar != Outpar && c == Bnull &&
 		      (str[1] == '$' || str[1] == '\\' || str[1] == '`' ||
 		       (qt && str[1] == '"'))))
-		    *str = ztokens[*str - Pound];
+		    *str = ztokens[c - Pound];
 	    str++;
 	    if (!(pl = getoutput(str2 + 1, qt || ssub))) {
 		zerr("parse error in command substitution", NULL, 0);
@@ -182,7 +186,7 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 	    l2 = strlen(s);
 	    if (nonempty(pl)) {
 		LinkNode n = lastnode(pl);
-		str2 = (char *) ncalloc(l1 + l2 + 1);
+		str2 = (char *) hcalloc(l1 + l2 + 1);
 		strcpy(str2, str3);
 		strcpy(str2 + l1, s);
 		setdata(node, str2);
@@ -191,7 +195,7 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 		l1 = 0;
 		l2 = strlen(s);
 	    }
-	    str2 = (char *) ncalloc(l1 + l2 + strlen(str) + 1);
+	    str2 = (char *) hcalloc(l1 + l2 + strlen(str) + 1);
 	    if (l1)
 		strcpy(str2, str3);
 	    strcpy(str2 + l1, s);
@@ -206,15 +210,15 @@ stringsubst(LinkList list, LinkNode node, int ssub)
 }
 
 /**/
-void
-globlist(LinkList list)
+mod_export void
+globlist(LinkList list, int nountok)
 {
     LinkNode node, next;
 
     badcshglob = 0;
     for (node = firstnode(list); !errflag && node; node = next) {
 	next = nextnode(node);
-	glob(list, node);
+	glob(list, node, nountok);
     }
     if (badcshglob == 1)
 	zerr("no match", NULL, 0);
@@ -223,71 +227,84 @@ globlist(LinkList list)
 /* perform substitution on a single word */
 
 /**/
-void
+mod_export void
 singsub(char **s)
 {
-    LinkList foo;
+    local_list1(foo);
 
-    foo = newlinklist();
-    addlinknode(foo, *s);
-    prefork(foo, 4);
+    init_list1(foo, *s);
+
+    prefork(&foo, PF_SINGLE);
     if (errflag)
 	return;
-    *s = (char *) ugetnode(foo);
-    DPUTS(nonempty(foo), "BUG: singsub() produced more than one word!");
+    *s = (char *) ugetnode(&foo);
+    DPUTS(nonempty(&foo), "BUG: singsub() produced more than one word!");
 }
 
 /* Perform substitution on a single word. Unlike with singsub, the      *
- * result can have more than one words. A single word result is sroted  *
+ * result can have more than one word. A single word result is stored   *
  * in *s and *isarr is set to zero; otherwise *isarr is set to 1 and    *
  * the result is stored in *a. If `a' is zero a multiple word result is *
  * joined using sep or the IFS parameter if sep is zero and the result  *
  * is returned in *s.  The return value is true iff the expansion       *
- * resulted in an empty list                                            */
+ * resulted in an empty list.                                           *
+ * The mult_isarr variable is used by paramsubst() to tell if it yields *
+ * an array.                                                            */
+
+/**/
+static int mult_isarr;
 
 /**/
 static int
 multsub(char **s, char ***a, int *isarr, char *sep)
 {
-    LinkList foo;
-    int l;
+    int l, omi = mult_isarr;
     char **r, **p;
+    local_list1(foo);
 
-    foo = newlinklist();
-    addlinknode(foo, *s);
-    prefork(foo, 0);
+    mult_isarr = 0;
+    init_list1(foo, *s);
+    prefork(&foo, 0);
     if (errflag) {
 	if (isarr)
 	    *isarr = 0;
+	mult_isarr = omi;
 	return 0;
     }
-    if ((l = countlinknodes(foo)) > 1) {
-	p = r = ncalloc((l + 1) * sizeof(char*));
-	while (nonempty(foo))
-	    *p++ = (char *)ugetnode(foo);
+    if ((l = countlinknodes(&foo))) {
+	p = r = hcalloc((l + 1) * sizeof(char*));
+	while (nonempty(&foo))
+	    *p++ = (char *)ugetnode(&foo);
 	*p = NULL;
-	if (a) {
+	if (a && mult_isarr) {
 	    *a = r;
-	    *isarr = 1;
+	    *isarr = SCANPM_MATCHMANY;
+	    mult_isarr = omi;
 	    return 0;
 	}
-	*s = sepjoin(r, NULL);
+	*s = sepjoin(r, NULL, 1);
+	mult_isarr = omi;
+	if (isarr)
+	    *isarr = 0;
 	return 0;
     }
     if (l)
-	*s = (char *) ugetnode(foo);
+	*s = (char *) ugetnode(&foo);
     else
 	*s = dupstring("");
     if (isarr)
 	*isarr = 0;
+    mult_isarr = omi;
     return !l;
 }
 
-/* ~, = subs: assign = 2 => typeset; assign = 1 => something that looks
-	like an assignment but may not be; assign = 3 => normal assignment */
+/*
+ * ~, = subs: assign & PF_TYPESET => typeset or magic equals
+ *            assign & PF_ASSIGN => normal assignment
+ */
 
 /**/
-void
+mod_export void
 filesub(char **namptr, int assign)
 {
     char *sub = NULL, *str, *ptr;
@@ -298,12 +315,8 @@ filesub(char **namptr, int assign)
     if (!assign)
 	return;
 
-    if (assign < 3)
+    if (assign & PF_TYPESET) {
 	if ((*namptr)[1] && (sub = strchr(*namptr + 1, Equals))) {
-	    if (assign == 1)
-		for (ptr = *namptr; ptr != sub; ptr++)
-		    if (!iident(*ptr) && !INULL(*ptr))
-			return;
 	    str = sub + 1;
 	    if ((sub[1] == Tilde || sub[1] == Equals) && filesubstr(&str, assign)) {
 		sub[1] = '\0';
@@ -311,6 +324,7 @@ filesub(char **namptr, int assign)
 	    }
 	} else
 	    return;
+    }
 
     ptr = *namptr;
     while ((sub = strchr(ptr, ':'))) {
@@ -325,7 +339,7 @@ filesub(char **namptr, int assign)
 }
 
 /**/
-int
+mod_export int
 filesubstr(char **namptr, int assign)
 {
 #define isend(c) ( !(c) || (c)=='/' || (c)==Inpar || (assign && (c)==':') )
@@ -382,11 +396,11 @@ filesubstr(char **namptr, int assign)
 	for (pp = str + 1; !isend2(*pp); pp++);
 	sav = *pp;
 	*pp = 0;
-	if (!(cnam = findcmd(str + 1))) {
+	if (!(cnam = findcmd(str + 1, 1))) {
 	    Alias a = (Alias) aliastab->getnode(aliastab, str + 1);
 	    
 	    if (a)
-		cnam = ztrdup(a->text);
+		cnam = a->text;
 	    else {
 		if (isset(NOMATCH))
 		    zerr("%s not found", str + 1, 0);
@@ -394,7 +408,6 @@ filesubstr(char **namptr, int assign)
 	    }
 	}
 	*namptr = dupstring(cnam);
-	zsfree(cnam);
 	if (sav) {
 	    *pp = sav;
 	    *namptr = dyncat(*namptr, pp);
@@ -408,20 +421,27 @@ filesubstr(char **namptr, int assign)
 
 /**/
 static char *
-strcatsub(char **d, char *pb, char *pe, char *src, int l, char *s, int glbsub)
+strcatsub(char **d, char *pb, char *pe, char *src, int l, char *s, int glbsub,
+	  int copied)
 {
+    char *dest;
     int pl = pe - pb;
-    char *dest = ncalloc(pl + l + (s ? strlen(s) : 0) + 1);
-
-    *d = dest;
-    strncpy(dest, pb, pl);
-    dest += pl;
-    strcpy(dest, src);
-    if (glbsub)
-	tokenize(dest);
-    dest += l;
-    if (s)
-	strcpy(dest, s);
+
+    if (!pl && (!s || !*s)) {
+	*d = dest = (copied ? src : dupstring(src));
+	if (glbsub)
+	    tokenize(dest);
+    } else {
+	*d = dest = hcalloc(pl + l + (s ? strlen(s) : 0) + 1);
+	strncpy(dest, pb, pl);
+	dest += pl;
+	strcpy(dest, src);
+	if (glbsub)
+	    tokenize(dest);
+	dest += l;
+	if (s)
+	    strcpy(dest, s);
+    }
     return dest;
 }
 
@@ -529,7 +549,7 @@ dopadding(char *str, int prenum, int postnum, char *preone, char *postone, char
     if (lr == ls)
 	return str;
 
-    r = ret = (char *)halloc(lr + 1);
+    r = ret = (char *)zhalloc(lr + 1);
 
     if (prenum) {
 	if (postnum) {
@@ -657,7 +677,7 @@ get_intarg(char **s)
 {
     char *t = get_strarg(*s + 1);
     char *p, sav;
-    long ret;
+    zlong ret;
 
     if (!*t)
 	return -1;
@@ -671,7 +691,7 @@ get_intarg(char **s)
     singsub(&p);
     if (errflag)
 	return -1;
-    ret = matheval(p);
+    ret = mathevali(p);
     if (errflag)
 	return -1;
     if (ret < 0)
@@ -679,6 +699,26 @@ get_intarg(char **s)
     return ret < 0 ? -ret : ret;
 }
 
+/* Parsing for the (e) flag. */
+
+static int
+subst_parse_str(char **sp, int single)
+{
+    char *s;
+
+    *sp = s = dupstring(*sp);
+
+    if (!parsestr(s)) {
+	if (!single) {
+	    for (; *s; s++)
+		if (*s == Qstring)
+		    *s = String;
+	}
+	return 0;
+    }
+    return 1;
+}
+
 /* parameter substitution */
 
 #define	isstring(c) ((c) == '$' || (char)(c) == String || (char)(c) == Qstring)
@@ -688,10 +728,9 @@ get_intarg(char **s)
 LinkNode
 paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 {
-    char *aptr = *str;
+    char *aptr = *str, c, cc;
     char *s = aptr, *fstr, *idbeg, *idend, *ostr = (char *) getdata(n);
     int colf;			/* != 0 means we found a colon after the name */
-    int doub = 0;		/* != 0 means we have %%, not %, or ##, not # */
     int isarr = 0;
     int plan9 = isset(RCEXPANDPARAM);
     int globsubst = isset(GLOBSUBST);
@@ -699,45 +738,58 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
     int whichlen = 0;
     int chkset = 0;
     int vunset = 0;
+    int wantt = 0;
     int spbreak = isset(SHWORDSPLIT) && !ssub && !qt;
     char *val = NULL, **aval = NULL;
     unsigned int fwidth = 0;
-    Value v;
+    struct value vbuf;
+    Value v = NULL;
     int flags = 0;
     int flnum = 0;
-    int substr = 0;
     int sortit = 0, casind = 0;
     int casmod = 0;
+    int quotemod = 0, quotetype = 0, quoteerr = 0;
+    int visiblemod = 0;
     char *sep = NULL, *spsep = NULL;
     char *premul = NULL, *postmul = NULL, *preone = NULL, *postone = NULL;
-    long prenum = 0, postnum = 0;
+    char *replstr = NULL;	/* replacement string for /orig/repl */
+    zlong prenum = 0, postnum = 0;
     int copied = 0;
     int arrasg = 0;
     int eval = 0;
+    int aspar = 0;
+    int presc = 0;
     int nojoin = 0;
     char inbrace = 0;		/* != 0 means ${...}, otherwise $... */
+    char hkeys = 0;
+    char hvals = 0;
+    int subexp;
 
     *s++ = '\0';
-    if (!ialnum(*s) && *s != '#' && *s != Pound && *s != '-' &&
-	*s != '!' && *s != '$' && *s != String && *s != Qstring &&
-	*s != '?' && *s != Quest && *s != '_' &&
-	*s != '*' && *s != Star && *s != '@' && *s != '{' &&
-	*s != Inbrace && *s != '=' && *s != Equals && *s != Hat &&
-	*s != '^' && *s != '~' && *s != Tilde && *s != '+') {
+    if (!ialnum(c = *s) && c != '#' && c != Pound && c != '-' &&
+	c != '!' && c != '$' && c != String && c != Qstring &&
+	c != '?' && c != Quest && c != '_' &&
+	c != '*' && c != Star && c != '@' && c != '{' &&
+	c != Inbrace && c != '=' && c != Equals && c != Hat &&
+	c != '^' && c != '~' && c != Tilde && c != '+') {
 	s[-1] = '$';
 	*str = s;
 	return n;
     }
-    DPUTS(*s == '{', "BUG: inbrace == '{' in paramsubst()");
-    if (*s == Inbrace) {
+    DPUTS(c == '{', "BUG: inbrace == '{' in paramsubst()");
+    if (c == Inbrace) {
 	inbrace = 1;
 	s++;
-	if (*s == '(' || *s == Inpar) {
+	if ((c = *s) == '!' && s[1] != Outbrace && emulation == EMULATE_KSH) {
+	    hkeys = SCANPM_WANTKEYS;
+	    s++;
+	} else if (c == '(' || c == Inpar) {
 	    char *t, sav;
 	    int tt = 0;
-	    long num;
+	    zlong num;
 	    int escapes = 0;
 	    int klen;
+#define UNTOK(C)  (itok(C) ? ztokens[(C) - Pound] : (C))
 #define UNTOK_AND_ESCAPE(X) {\
 		untokenize(X = dupstring(s + 1));\
 		if (escapes) {\
@@ -746,34 +798,34 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		}\
 	    }
 
-	    for (s++; *s != ')' && *s != Outpar; s++, tt = 0) {
-		switch (*s) {
+	    for (s++; (c = *s) != ')' && c != Outpar; s++, tt = 0) {
+		switch (c) {
 		case ')':
 		case Outpar:
 		    break;
 		case 'A':
-		    arrasg = 1;
+		    ++arrasg;
 		    break;
 		case '@':
 		    nojoin = 1;
 		    break;
 		case 'M':
-		    flags |= 8;
+		    flags |= SUB_MATCH;
 		    break;
 		case 'R':
-		    flags |= 16;
+		    flags |= SUB_REST;
 		    break;
 		case 'B':
-		    flags |= 32;
+		    flags |= SUB_BIND;
 		    break;
 		case 'E':
-		    flags |= 64;
+		    flags |= SUB_EIND;
 		    break;
 		case 'N':
-		    flags |= 128;
+		    flags |= SUB_LEN;
 		    break;
 		case 'S':
-		    substr = 1;
+		    flags |= SUB_SUBSTR;
 		    break;
 		case 'I':
 		    flnum = get_intarg(&s);
@@ -800,9 +852,27 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		case 'i':
 		    casind = 1;
 		    break;
+
+		case 'V':
+		    visiblemod++;
+		    break;
+
+		case 'q':
+		    quotemod++, quotetype++;
+		    break;
+		case 'Q':
+		    quotemod--;
+		    break;
+		case 'X':
+		    quoteerr = 1;
+		    break;
+
 		case 'e':
 		    eval = 1;
 		    break;
+		case 'P':
+		    aspar = 1;
+		    break;
 
 		case 'c':
 		    whichlen = 1;
@@ -851,7 +921,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 			prenum = num;
 		    else
 			postnum = num;
-		    if (s[1] != sav)
+		    if (UNTOK(s[1]) != UNTOK(sav))
 			break;
 		    t = get_strarg(++s);
 		    if (!*t)
@@ -865,7 +935,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    *t = sav;
 		    sav = *s;
 		    s = t + 1;
-		    if (*s != sav) {
+		    if (UNTOK(*s) != UNTOK(sav)) {
 			s--;
 			break;
 		    }
@@ -886,6 +956,21 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    escapes = 1;
 		    break;
 
+		case 'k':
+		    hkeys = SCANPM_WANTKEYS;
+		    break;
+		case 'v':
+		    hvals = SCANPM_WANTVALS;
+		    break;
+
+		case 't':
+		    wantt = 1;
+		    break;
+
+		case '%':
+		    presc++;
+		    break;
+
 		default:
 		  flagerr:
 		    zerr("error in flags", NULL, 0);
@@ -904,31 +989,33 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	postmul = " ";
 
     for (;;) {
-	if (*s == '^' || *s == Hat) {
-	    if (*++s == '^' || *s == Hat) {
+	if ((c = *s) == '^' || c == Hat) {
+	    if ((c = *++s) == '^' || c == Hat) {
 		plan9 = 0;
 		s++;
 	    } else
 		plan9 = 1;
-	} else if (*s == '=' || *s == Equals) {
-	    if (*++s == '=' || *s == Equals) {
+	} else if ((c = *s) == '=' || c == Equals) {
+	    if ((c = *++s) == '=' || c == Equals) {
 		spbreak = 0;
 		s++;
 	    } else
 		spbreak = 1;
-	} else if ((*s == '#' || *s == Pound) &&
-		   (iident(s[1])
-		    || s[1] == '*' || s[1] == Star || s[1] == '@'
-		    || (isstring(s[1]) && (s[2] == Inbrace || s[2] == Inpar))))
+	} else if ((c == '#' || c == Pound) &&
+		   (iident(cc = s[1])
+		    || cc == '*' || cc == Star || cc == '@'
+		    || cc == '-' || (cc == ':' && s[2] == '-')
+		    || (isstring(cc) && (s[2] == Inbrace || s[2] == Inpar))))
 	    getlen = 1 + whichlen, s++;
-	else if (*s == '~' || *s == Tilde) {
-	    if (*++s == '~' || *s == Tilde) {
+	else if (c == '~' || c == Tilde) {
+	    if ((c = *++s) == '~' || c == Tilde) {
 		globsubst = 0;
 		s++;
 	    } else
 		globsubst = 1;
-	} else if (*s == '+')
-	    if (iident(s[1]))
+	} else if (c == '+') {
+	    if (iident(s[1]) || (aspar && isstring(s[1]) &&
+				 (s[2] == Inbrace || s[2] == Inpar)))
 		chkset = 1, s++;
 	    else if (!inbrace) {
 		*aptr = '$';
@@ -938,13 +1025,16 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		zerr("bad substitution", NULL, 0);
 		return NULL;
 	    }
+	} else if (inbrace && INULL(*s))
+	    s++;
 	else
 	    break;
     }
     globsubst = globsubst && !qt;
 
     idbeg = s;
-    if (s[-1] && isstring(*s) && (s[1] == Inbrace || s[1] == Inpar)) {
+    if ((subexp = (inbrace && s[-1] && isstring(*s) &&
+		   (s[1] == Inbrace || s[1] == Inpar)))) {
 	int sav;
 	int quoted = *s == Qstring;
 
@@ -952,17 +1042,78 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	skipparens(*s, *s == Inpar ? Outpar : Outbrace, &s);
 	sav = *s;
 	*s = 0;
-	if (multsub(&val, &aval, &isarr, NULL) && quoted) {
-	    isarr = -1;
-	    aval = alloc(sizeof(char *));
-	}
-	if (isarr)
+	if (multsub(&val, (aspar ? NULL : &aval), &isarr, NULL) && quoted) {
 	    isarr = -1;
-	copied = 1;
+	    aval = (char **) hcalloc(sizeof(char *));
+	    aspar = 0;
+	} else if (aspar)
+	    idbeg = val;
 	*s = sav;
+	while (INULL(*s))
+	    s++;
 	v = (Value) NULL;
-    } else if (!(v = getvalue(&s, (unset(KSHARRAYS) || inbrace) ? 1 : -1)))
-	vunset = 1;
+    } else if (aspar) {
+	if ((v = getvalue(&vbuf, &s, 1))) {
+	    val = idbeg = getstrvalue(v);
+	    subexp = 1;
+	} else
+	    vunset = 1;
+    }
+    if (!subexp || aspar) {
+	char *ov = val;
+
+	if (!(v = fetchvalue(&vbuf, (subexp ? &ov : &s),
+			     (wantt ? -1 :
+			      ((unset(KSHARRAYS) || inbrace) ? 1 : -1)),
+			     hkeys|hvals|(arrasg ? SCANPM_ASSIGNING : 0))) ||
+	    (v->pm && (v->pm->flags & PM_UNSET)))
+	    vunset = 1;
+
+	if (wantt) {
+	    if (v && v->pm && !(v->pm->flags & PM_UNSET)) {
+		int f = v->pm->flags;
+
+		switch (PM_TYPE(f)) {
+		case PM_SCALAR:  val = "scalar"; break;
+		case PM_ARRAY:   val = "array"; break;
+		case PM_INTEGER: val = "integer"; break;
+		case PM_EFLOAT:
+		case PM_FFLOAT:  val = "float"; break;
+		case PM_HASHED:  val = "association"; break;
+		}
+		val = dupstring(val);
+		if (v->pm->level)
+		    val = dyncat(val, "-local");
+		if (f & PM_LEFT)
+		    val = dyncat(val, "-left");
+		if (f & PM_RIGHT_B)
+		    val = dyncat(val, "-right_blanks");
+		if (f & PM_RIGHT_Z)
+		    val = dyncat(val, "-right_zeros");
+		if (f & PM_LOWER)
+		    val = dyncat(val, "-lower");
+		if (f & PM_UPPER)
+		    val = dyncat(val, "-upper");
+		if (f & PM_READONLY)
+		    val = dyncat(val, "-readonly");
+		if (f & PM_TAGGED)
+		    val = dyncat(val, "-tag");
+		if (f & PM_EXPORTED)
+		    val = dyncat(val, "-export");
+		if (f & PM_UNIQUE)
+		    val = dyncat(val, "-unique");
+		if (f & PM_HIDE)
+		    val = dyncat(val, "-hide");
+		if (f & PM_SPECIAL)
+		    val = dyncat(val, "-special");
+		vunset = 0;
+	    } else
+		val = dupstring("");
+
+	    v = NULL;
+	    isarr = 0;
+	}
+    }
     while (v || ((inbrace || (unset(KSHARRAYS) && vunset)) && isbrack(*s))) {
 	if (!v) {
 	    Param pm;
@@ -986,9 +1137,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    if (getindex(&s, v) || s == os)
 		break;
 	}
-	if ((isarr = v->isarr))
-	    aval = getarrvalue(v);
-	else {
+	if ((isarr = v->isarr)) {
+	    /* No way to get here with v->inv != 0, so getvaluearr() *
+	     * is called by getarrvalue(); needn't test PM_HASHED.   */
+	    if (v->isarr == SCANPM_WANTINDEX) {
+		isarr = v->isarr = 0;
+		val = dupstring(v->pm->nam);
+	    } else
+		aval = getarrvalue(v);
+	} else {
 	    if (v->pm->flags & PM_ARRAY) {
 		int tmplen = arrlen(v->pm->gets.afn(v->pm));
 
@@ -1013,7 +1170,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    else
 			while (iblank(*t))
 			    t++;
-		    val = (char *)ncalloc(fwidth + 1);
+		    val = (char *) hcalloc(fwidth + 1);
 		    val[fwidth] = '\0';
 		    if ((t0 = strlen(t)) > fwidth)
 			t0 = fwidth;
@@ -1023,18 +1180,28 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		case PM_RIGHT_B:
 		case PM_RIGHT_Z:
 		case PM_RIGHT_Z | PM_RIGHT_B:
-		    if (strlen(val) < fwidth) {
-			t = (char *)ncalloc(fwidth + 1);
-			memset(t, (v->pm->flags & PM_RIGHT_B) ? ' ' : '0', fwidth);
-			if ((t0 = strlen(val)) > fwidth)
-			    t0 = fwidth;
-			strcpy(t + (fwidth - t0), val);
-			val = t;
-		    } else {
-			t = (char *)ncalloc(fwidth + 1);
-			t[fwidth] = '\0';
-			strncpy(t, val + strlen(val) - fwidth, fwidth);
-			val = t;
+		    {
+			int zero = 1;
+
+			if (strlen(val) < fwidth) {
+			    if (v->pm->flags & PM_RIGHT_Z) {
+				for (t = val; iblank(*t); t++);
+				if (!*t || !idigit(*t))
+				    zero = 0;
+			    }
+			    t = (char *) hcalloc(fwidth + 1);
+			    memset(t, (((v->pm->flags & PM_RIGHT_B) || !zero) ?
+				       ' ' : '0'), fwidth);
+			    if ((t0 = strlen(val)) > fwidth)
+				t0 = fwidth;
+			    strcpy(t + (fwidth - t0), val);
+			    val = t;
+			} else {
+			    t = (char *) hcalloc(fwidth + 1);
+			    t[fwidth] = '\0';
+			    strncpy(t, val + strlen(val) - fwidth, fwidth);
+			    val = t;
+			}
 		    }
 		    break;
 		}
@@ -1043,13 +1210,13 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 
 		case PM_LOWER:
 		    t = val;
-		    for (; *t; t++)
-			*t = tulower(*t);
+		    for (; (c = *t); t++)
+			*t = tulower(c);
 		    break;
 		case PM_UPPER:
 		    t = val;
-		    for (; *t; t++)
-			*t = tuupper(*t);
+		    for (; (c = *t); t++)
+			*t = tuupper(c);
 		    break;
 		}
 	    }
@@ -1062,12 +1229,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	if (nojoin)
 	    isarr = -1;
 	if (qt && !getlen && isarr > 0) {
-	    val = sepjoin(aval, sep);
+	    val = sepjoin(aval, sep, 1);
 	    isarr = 0;
 	}
     }
 
     idend = s;
+    if (inbrace)
+	while (INULL(*s))
+	    s++;
     if ((colf = *s == ':'))
 	s++;
 
@@ -1077,12 +1247,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
     fstr = s;
     if (inbrace) {
 	int bct;
-	for (bct = 1;; fstr++) {
-	    if (!*fstr)
-		break;
-	    else if (*fstr == Inbrace)
+	for (bct = 1; (c = *fstr); fstr++) {
+	    if (c == Inbrace)
 		bct++;
-	    else if (*fstr == Outbrace && !--bct)
+	    else if (c == Outbrace && !--bct)
 		break;
 	}
 
@@ -1091,36 +1259,83 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    zerr("closing brace expected", NULL, 0);
 	    return NULL;
 	}
-	if (*fstr)
+	if (c)
 	    *fstr++ = '\0';
     }
 
     /* Check for ${..?..} or ${..=..} or one of those. *
      * Only works if the name is in braces.            */
 
-    if (inbrace && (*s == '-' ||
-		    *s == '+' ||
-		    *s == ':' ||
-		    *s == '=' || *s == Equals ||
-		    *s == '%' ||
-		    *s == '#' || *s == Pound ||
-		    *s == '?' || *s == Quest)) {
+    if (inbrace && ((c = *s) == '-' ||
+		    c == '+' ||
+		    c == ':' ||
+		    c == '=' || c == Equals ||
+		    c == '%' ||
+		    c == '#' || c == Pound ||
+		    c == '?' || c == Quest ||
+		    c == '/')) {
 
 	if (!flnum)
 	    flnum++;
-	if (*s == '%')
-	    flags |= 1;
+	if (c == '%')
+	    flags |= SUB_END;
 
 	/* Check for ${..%%..} or ${..##..} */
-	if ((*s == '%' || *s == '#' || *s == Pound) && *s == s[1]) {
+	if ((c == '%' || c == '#' || c == Pound) && c == s[1]) {
 	    s++;
-	    doub = 1;
+	    /* we have %%, not %, or ##, not # */
+	    flags |= SUB_LONG;
 	}
 	s++;
+	if (s[-1] == '/') {
+	    char *ptr;
+	    /*
+	     * previous flags are irrelevant, except for (S) which
+	     * indicates shortest substring; else look for longest.
+	     */
+	    flags = (flags & SUB_SUBSTR) ? 0 : SUB_LONG;
+	    if ((c = *s) == '/') {
+		/* doubled, so replace all occurrences */
+		flags |= SUB_GLOBAL;
+		s++;
+	    }
+	    /* Check for anchored substitution */
+	    if (c == '%') {
+		/* anchor at tail */
+		flags |= SUB_END;
+		s++;
+	    } else if (c == '#' || c == Pound) {
+		/* anchor at head: this is the `normal' case in getmatch */
+		s++;
+	    } else
+		flags |= SUB_SUBSTR;
+	    /*
+	     * Find the / marking the end of the search pattern.
+	     * If there isn't one, we're just going to delete that,
+	     * i.e. replace it with an empty string.
+	     *
+	     * This allows quotation of the slash with '\\/'. Why
+	     * two?  Well, for a non-quoted string we can check for
+	     * Bnull+/, which is what you get from `\/', but inside
+	     * double quotes the Bnull isn't there, so it's not
+	     * consistent.
+	     */
+	    for (ptr = s; (c = *ptr) && c != '/'; ptr++)
+		if (c == '\\' && ptr[1] == '/')
+		    chuck(ptr);
+	    replstr = (*ptr && ptr[1]) ? ptr+1 : "";
+	    *ptr = '\0';
+	}
 
-	flags |= (doub << 1) | (substr << 2) | (colf << 8);
-	if (!(flags & 0xf8))
-	    flags |= 16;
+	if (colf)
+	    flags |= SUB_ALL;
+	/*
+	 * With no special flags, i.e. just a # or % or whatever,
+	 * the matched portion is removed and we keep the rest.
+	 * We also want the rest when we're doing a substitution.
+	 */
+	if (!(flags & (SUB_MATCH|SUB_REST|SUB_BIND|SUB_EIND|SUB_LEN)))
+	    flags |= SUB_REST;
 
 	if (colf && !vunset)
 	    vunset = (isarr) ? !*aval : !*val || (*val == Nularg && !val[1]);
@@ -1138,7 +1353,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	case '-':
 	    if (vunset) {
 		val = dupstring(s);
-		multsub(&val, &aval, &isarr, NULL);
+		multsub(&val, NULL, &isarr, NULL);
 		copied = 1;
 	    }
 	    break;
@@ -1164,7 +1379,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		if (arrasg) {
 		    char *arr[2], **t, **a, **p;
 		    if (spsep || spbreak) {
-			aval = sepsplit(val, spsep, 0);
+			aval = sepsplit(val, spsep, 0, 1);
 			isarr = 2;
 			sep = spsep = NULL;
 			spbreak = 0;
@@ -1176,10 +1391,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 			else
 			    t = aval;
 		    } else if (!isarr) {
-			arr[0] = val;
-			arr[1] = NULL;
+			if (!*val && arrasg > 1) {
+			    arr[0] = NULL;
+			    l = 0;
+			} else {
+			    arr[0] = val;
+			    arr[1] = NULL;
+			    l = 1;
+			}
 			t = aval = arr;
-			l = 1;
 		    } else
 			l = arrlen(aval), t = aval;
 		    p = a = zalloc(sizeof(char *) * (l + 1));
@@ -1188,7 +1408,12 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 			*p++ = ztrdup(*t++);
 		    }
 		    *p++ = NULL;
-		    setaparam(idbeg, a);
+		    if (arrasg > 1) {
+			Param pm = sethparam(idbeg, a);
+			if (pm)
+			    aval = paramvalarr(pm->gets.hfn(pm), hkeys|hvals);
+		    } else
+			setaparam(idbeg, a);
 		} else {
 		    untokenize(val);
 		    setsparam(idbeg, ztrdup(val));
@@ -1214,27 +1439,47 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	case '%':
 	case '#':
 	case Pound:
-	    if (qt)
-		if (parse_subst_string(s)) {
+	case '/':
+	    if (qt) {
+		int one = noerrs, oef = errflag, haserr;
+
+		if (!quoteerr)
+		    noerrs = 1;
+		haserr = parse_subst_string(s);
+		noerrs = one;
+		if (!quoteerr) {
+		    errflag = oef;
+		    if (haserr)
+			tokenize(s);
+		} else if (haserr || errflag) {
 		    zerr("parse error in ${...%c...} substitution",
 			 NULL, s[-1]);
 		    return NULL;
 		}
-	    singsub(&s);
+	    }
+	    {
+		char t = s[-1];
+
+		singsub(&s);
+		if (t == '/' && (flags & SUB_SUBSTR)) {
+		    if ((c = *s) == '#' || c == '%') {
+			flags &= ~SUB_SUBSTR;
+			if (c == '%')
+			    flags |= SUB_END;
+			s++;
+		    } else if (c == '\\') {
+			s++;
+		    }
+		}
+	    }
 
 	    if (!vunset && isarr) {
-		char **ap = aval;
-		char **pp = aval = (char **)ncalloc(sizeof(char *) * (arrlen(aval) + 1));
-
-		while ((*pp = *ap++)) {
-		    if (getmatch(pp, s, flags, flnum))
-			pp++;
-		}
+		getmatcharr(&aval, s, flags, flnum, replstr);
 		copied = 1;
 	    } else {
 		if (vunset)
 		    val = dupstring("");
-		getmatch(&val, s, flags, flnum);
+		getmatch(&val, s, flags, flnum, replstr);
 		copied = 1;
 	    }
 	    break;
@@ -1259,7 +1504,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		else {
 		    char *ss;
 		    char **ap = aval;
-		    char **pp = aval = (char **)ncalloc(sizeof(char *) * (arrlen(aval) + 1));
+		    char **pp = aval = (char **) hcalloc(sizeof(char *) *
+							 (arrlen(aval) + 1));
 
 		    while ((*pp = *ap++)) {
 			ss = s;
@@ -1272,6 +1518,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    }
 		    s = ss;
 		}
+		copied = 1;
 		if (inbrace && *s) {
 		    if (*s == ':' && !imeta(s[1]))
 			zerr("unrecognized modifier `%c'", NULL, s[1]);
@@ -1316,10 +1563,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	val = dupstring(buf);
 	isarr = 0;
     }
+    mult_isarr = isarr;
     if (isarr > 0 && !plan9 && (!aval || !aval[0])) {
 	val = dupstring("");
 	isarr = 0;
     } else if (isarr && aval && aval[0] && !aval[1]) {
+	/* treat a one-element array as a scalar for purposes of   *
+	 * concatenation with surrounding text (some${param}thing) *
+	 * and rc_expand_param handling.  Note: mult_isarr (above) *
+	 * propagates the true array type from nested expansions.  */
 	val = aval[0];
 	isarr = 0;
     }
@@ -1327,9 +1579,9 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
      * It means that we must join arrays and should not split words. */
     if (ssub || spbreak || spsep || sep) {
 	if (isarr)
-	    val = sepjoin(aval, sep), isarr = 0;
+	    val = sepjoin(aval, sep, 1), isarr = 0;
 	if (!ssub && (spbreak || spsep)) {
-	    aval = sepsplit(val, spsep, 0);
+	    aval = sepsplit(val, spsep, 0, 1);
 	    if (!aval || !aval[0])
 		val = dupstring("");
 	    else if (!aval[1])
@@ -1337,6 +1589,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    else
 		isarr = 2;
 	}
+	mult_isarr = isarr;
     }
     if (casmod) {
 	if (isarr) {
@@ -1367,6 +1620,134 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		makecapitals(&val);
 	}
     }
+    if (presc) {
+	int ops = opts[PROMPTSUBST], opb = opts[PROMPTBANG];
+	int opp = opts[PROMPTPERCENT], len;
+
+	if (presc < 2) {
+	    opts[PROMPTPERCENT] = 1;
+	    opts[PROMPTSUBST] = opts[PROMPTBANG] = 0;
+	}
+	if (isarr) {
+	    char **ap;
+
+	    if (!copied)
+		aval = arrdup(aval), copied = 1;
+	    ap = aval;
+	    for (; *ap; ap++) {
+		unmetafy(*ap, &len);
+		untokenize(*ap);
+		*ap = unmetafy(promptexpand(metafy(*ap, len, META_NOALLOC),
+					    0, NULL, NULL), &len);
+	    }
+	} else {
+	    if (!copied)
+		val = dupstring(val), copied = 1;
+	    unmetafy(val, &len);
+	    untokenize(val);
+	    val = unmetafy(promptexpand(metafy(val, len, META_NOALLOC),
+					0, NULL, NULL), &len);
+	}
+	opts[PROMPTSUBST] = ops;
+	opts[PROMPTBANG] = opb;
+	opts[PROMPTPERCENT] = opp;
+    }
+    if (quotemod) {
+	if (--quotetype > 3)
+	    quotetype = 3;
+	if (isarr) {
+	    char **ap;
+
+	    if (!copied)
+		aval = arrdup(aval), copied = 1;
+	    ap = aval;
+
+	    if (quotemod > 0) {
+		if (quotetype) {
+		    int sl;
+		    char *tmp;
+
+		    for (; *ap; ap++) {
+			int pre = quotetype != 3 ? 1 : 2;
+			tmp = bslashquote(*ap, NULL, quotetype);
+			sl = strlen(tmp);
+			*ap = (char *) zhalloc(pre + sl + 2);
+			strcpy((*ap) + pre, tmp);
+			ap[0][pre - 1] = ap[0][pre + sl] = (quotetype != 2 ? '\'' : '"');
+			ap[0][pre + sl + 1] = '\0';
+			if (quotetype == 3)
+			  ap[0][0] = '$';
+		    }
+		} else
+		    for (; *ap; ap++)
+			*ap = bslashquote(*ap, NULL, 0);
+	    } else {
+		int one = noerrs, oef = errflag, haserr = 0;
+
+		if (!quoteerr)
+		    noerrs = 1;
+		for (; *ap; ap++) {
+		    haserr |= parse_subst_string(*ap);
+		    remnulargs(*ap);
+		    untokenize(*ap);
+		}
+		noerrs = one;
+		if (!quoteerr)
+		    errflag = oef;
+		else if (haserr || errflag) {
+		    zerr("parse error in parameter value", NULL, 0);
+		    return NULL;
+		}
+	    }
+	} else {
+	    if (!copied)
+		val = dupstring(val), copied = 1;
+	    if (quotemod > 0) {
+		if (quotetype) {
+		    int pre = quotetype != 3 ? 1 : 2;
+		    int sl;
+		    char *tmp;
+		    tmp = bslashquote(val, NULL, quotetype);
+		    sl = strlen(tmp);
+		    val = (char *) zhalloc(pre + sl + 2);
+		    strcpy(val + pre, tmp);
+		    val[pre - 1] = val[pre + sl] = (quotetype != 2 ? '\'' : '"');
+		    val[pre + sl + 1] = '\0';
+		    if (quotetype == 3)
+		      val[0] = '$';
+		} else
+		    val = bslashquote(val, NULL, 0);
+	    } else {
+		int one = noerrs, oef = errflag, haserr;
+
+		if (!quoteerr)
+		    noerrs = 1;
+		haserr = parse_subst_string(val);
+		noerrs = one;
+		if (!quoteerr)
+		    errflag = oef;
+		else if (haserr || errflag) {
+		    zerr("parse error in parameter value", NULL, 0);
+		    return NULL;
+		}
+		remnulargs(val);
+		untokenize(val);
+	    }
+	}
+    }
+    if (visiblemod) {
+	if (isarr) {
+	    char **ap;
+	    if (!copied)
+		aval = arrdup(aval), copied = 1;
+	    for (ap = aval; *ap; ap++)
+		*ap = nicedupstring(*ap);
+	} else {
+	    if (!copied)
+		val = dupstring(val), copied = 1;
+	    val = nicedupstring(val);
+	}
+    }
     if (isarr) {
 	char *x;
 	char *y;
@@ -1378,7 +1759,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    if (aptr > (char *) getdata(n) &&
 		aptr[-1] == Dnull && *fstr == Dnull)
 		*--aptr = '\0', fstr++;
-	    y = (char *)ncalloc((aptr - ostr) + strlen(fstr) + 1);
+	    y = (char *) hcalloc((aptr - ostr) + strlen(fstr) + 1);
 	    strcpy(y, ostr);
 	    *str = y + (aptr - ostr);
 	    strcpy(*str, fstr);
@@ -1398,26 +1779,27 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		qsort(aval, i, sizeof(char *), sortfn[sortit-1]);
 	}
 	if (plan9) {
-	    LinkList tl = newlinklist();
 	    LinkNode tn;
+	    local_list1(tl);
 
 	    *--fstr = Marker;
-	    addlinknode(tl, fstr);
-	    if (!eval && !stringsubst(tl, firstnode(tl), ssub))
+	    init_list1(tl, fstr);
+	    if (!eval && !stringsubst(&tl, firstnode(&tl), ssub))
 		return NULL;
 	    *str = aptr;
-	    tn = firstnode(tl);
+	    tn = firstnode(&tl);
 	    while ((x = *aval++)) {
 		if (prenum || postnum)
 		    x = dopadding(x, prenum, postnum, preone, postone,
 				  premul, postmul);
-		if (eval && parsestr(x))
+		if (eval && subst_parse_str(&x, (qt && !nojoin)))
 		    return NULL;
 		xlen = strlen(x);
-		for (tn = firstnode(tl);
+		for (tn = firstnode(&tl);
 		     tn && *(y = (char *) getdata(tn)) == Marker;
 		     incnode(tn)) {
-		    strcatsub(&y, ostr, aptr, x, xlen, y + 1, globsubst);
+		    strcatsub(&y, ostr, aptr, x, xlen, y + 1, globsubst,
+			      copied);
 		    if (qt && !*y && isarr != 2)
 			y = dupstring(nulstring);
 		    if (plan9)
@@ -1446,10 +1828,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    if (prenum || postnum)
 		x = dopadding(x, prenum, postnum, preone, postone,
 			      premul, postmul);
-	    if (eval && parsestr(x))
+	    if (eval && subst_parse_str(&x, (qt && !nojoin)))
 		return NULL;
 	    xlen = strlen(x);
-	    strcatsub(&y, ostr, aptr, x, xlen, NULL, globsubst);
+	    strcatsub(&y, ostr, aptr, x, xlen, NULL, globsubst, copied);
 	    if (qt && !*y && isarr != 2)
 		y = dupstring(nulstring);
 	    setdata(n, (void *) y);
@@ -1461,7 +1843,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		if (prenum || postnum)
 		    x = dopadding(x, prenum, postnum, preone, postone,
 				  premul, postmul);
-		if (eval && parsestr(x))
+		if (eval && subst_parse_str(&x, (qt && !nojoin)))
 		    return NULL;
 		if (qt && !*x && isarr != 2)
 		    y = dupstring(nulstring);
@@ -1477,10 +1859,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	    if (prenum || postnum)
 		x = dopadding(x, prenum, postnum, preone, postone,
 			      premul, postmul);
-	    if (eval && parsestr(x))
+	    if (eval && subst_parse_str(&x, (qt && !nojoin)))
 		return NULL;
 	    xlen = strlen(x);
-	    *str = strcatsub(&y, aptr, aptr, x, xlen, fstr, globsubst);
+	    *str = strcatsub(&y, aptr, aptr, x, xlen, fstr, globsubst, copied);
 	    if (qt && !*y && isarr != 2)
 		y = dupstring(nulstring);
 	    insertlinknode(l, n, (void *) y), incnode(n);
@@ -1496,11 +1878,11 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 	if (prenum || postnum)
 	    x = dopadding(x, prenum, postnum, preone, postone,
 			  premul, postmul);
-	if (eval && parsestr(x))
+	if (eval && subst_parse_str(&x, (qt && !nojoin)))
 	    return NULL;
 	xlen = strlen(x);
-	*str = strcatsub(&y, ostr, aptr, x, xlen, fstr, globsubst);
-	if (qt && !*y && isarr != 2)
+	*str = strcatsub(&y, ostr, aptr, x, xlen, fstr, globsubst, copied);
+	if (qt && !*y)
 	    y = dupstring(nulstring);
 	setdata(n, (void *) y);
     }
@@ -1522,14 +1904,18 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 static char *
 arithsubst(char *a, char **bptr, char *rest)
 {
-    char *s = *bptr, *t, buf[DIGBUFSIZE];
-    char *b = buf;
-    long v;
+    char *s = *bptr, *t;
+    char buf[DIGBUFSIZE], *b = buf;
+    mnumber v;
 
     singsub(&a);
     v = matheval(a);
-    sprintf(buf, "%ld", v);
-    t = *bptr = (char *)ncalloc(strlen(*bptr) + strlen(buf) + strlen(rest) + 1);
+    if (v.type & MN_FLOAT)
+	b = convfloat(v.u.d, 0, 0, NULL);
+    else
+	convbase(buf, v.u.l, 0);
+    t = *bptr = (char *) hcalloc(strlen(*bptr) + strlen(b) + 
+				 strlen(rest) + 1);
     t--;
     while ((*++t = *s++));
     t--;
@@ -1567,6 +1953,8 @@ modify(char **str, char **ptr)
 	    case 't':
 	    case 'l':
 	    case 'u':
+	    case 'q':
+	    case 'Q':
 		c = **ptr;
 		break;
 
@@ -1587,7 +1975,7 @@ modify(char **str, char **ptr)
 		if (*ptr1) {
 		    zsfree(hsubl);
 		    hsubl = ztrdup(ptr1);
-		}
+ 		}
 		if (!hsubl) {
 		    zerr("no previous substitution", NULL, 0);
 		    return;
@@ -1685,11 +2073,26 @@ modify(char **str, char **ptr)
 			if (hsubl && hsubr)
 			    subst(&copy, hsubl, hsubr, gbal);
 			break;
+		    case 'q':
+			copy = bslashquote(copy, NULL, 0);
+			break;
+		    case 'Q':
+			{
+			    int one = noerrs, oef = errflag;
+
+			    noerrs = 1;
+			    parse_subst_string(copy);
+			    noerrs = one;
+			    errflag = oef;
+			    remnulargs(copy);
+			    untokenize(copy);
+			}
+			break;
 		    }
 		    tc = *tt;
 		    *tt = '\0';
 		    nl = al + strlen(t) + strlen(copy);
-		    ptr1 = tmp = (char *)halloc(nl + 1);
+		    ptr1 = tmp = (char *)zhalloc(nl + 1);
 		    if (all)
 			for (ptr2 = all; *ptr2;)
 			    *ptr1++ = *ptr2++;
@@ -1736,6 +2139,21 @@ modify(char **str, char **ptr)
 			}
 		    }
 		    break;
+		case 'q':
+		    *str = bslashquote(*str, NULL, 0);
+		    break;
+		case 'Q':
+		    {
+			int one = noerrs, oef = errflag;
+
+			noerrs = 1;
+			parse_subst_string(*str);
+			noerrs = one;
+			errflag = oef;
+			remnulargs(*str);
+			untokenize(*str);
+		    }
+		    break;
 		}
 	    }
 	    if (rec < 0) {
@@ -1765,6 +2183,8 @@ dstackent(char ch, int val)
     else
 	for (end=NULL, n=firstnode(dirstack); n && val; val--, n=nextnode(n));
     if (n == end) {
+	if (backwards && !val)
+	    return pwd;
 	if (isset(NOMATCH))
 	    zerr("not enough directory stack entries.", NULL, 0);
 	return NULL;