FCL/sf/mw/appsupport: comparison openenvutils/commandshell/shell/src/subst.c

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--1:000000000000
+:2e3d3ce01487
+// subst.c - various substitutions
+//
+// © Portions Copyright (c) Symbian Software Ltd 2007. All rights reserved.
+//
+/*
+* This file is part of zsh, the Z shell.
+*
+* Copyright (c) 1992-1997 Paul Falstad
+* All rights reserved.
+*
+* Permission is hereby granted, without written agreement and without
+* license or royalty fees, to use, copy, modify, and distribute this
+* software and to distribute modified versions of this software for any
+* purpose, provided that the above copyright notice and the following
+* two paragraphs appear in all copies of this software.
+*
+* In no event shall Paul Falstad or the Zsh Development Group be liable
+* to any party for direct, indirect, special, incidental, or consequential
+* damages arising out of the use of this software and its documentation,
+* even if Paul Falstad and the Zsh Development Group have been advised of
+* the possibility of such damage.
+*
+* Paul Falstad and the Zsh Development Group specifically disclaim any
+* warranties, including, but not limited to, the implied warranties of
+* merchantability and fitness for a particular purpose.  The software
+* provided hereunder is on an "as is" basis, and Paul Falstad and the
+* Zsh Development Group have no obligation to provide maintenance,
+* support, updates, enhancements, or modifications.
+*
+*/
+#include "zsh.mdh"
+#include "subst.pro"
+#ifdef __SYMBIAN32__
+#ifdef __WINSCW__
+#pragma warn_possunwant off
+#endif//__WINSCW__
+#endif//__SYMBIAN32__
+/**/
+char nulstring[] = {Nularg, '\0'};
+/* Do substitutions before fork. These are:
+*  - Process substitution: <(...), >(...), =(...)
+*  - Parameter substitution
+*  - Command substitution
+* Followed by
+*  - Quote removal
+*  - Brace expansion
+*  - Tilde and equals substitution
+*
+* PF_* flags are defined in zsh.h
+*/
+/**/
+mod_export void
+prefork(LinkList list, int flags)
+{
+LinkNode node, stop = 0;
+int keep = 0, asssub = (flags & PF_TYPESET) && isset(KSHTYPESET);
+queue_signals();
+for (node = firstnode(list); node; incnode(node)) {
+	char *str, c;
+	str = (char *)getdata(node);
+	if (((c = *str) == Inang || c == Outang || c == Equals) &&
+	    str[1] == Inpar) {
+	    if (c == Inang || c == Outang)
+		setdata(node, (void *) getproc(str));	/* <(...) or >(...) */
+	    else
+		setdata(node, (void *) getoutputfile(str));	/* =(...) */
+	    if (!getdata(node)) {
+		unqueue_signals();
+		return;
+	    }
+	} else {
+	    if (isset(SHFILEEXPANSION))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	    if (!(node = stringsubst(list, node, flags & PF_SINGLE, asssub))) {
+		unqueue_signals();
+		return;
+	    }
+	}
+}
+for (node = firstnode(list); node; incnode(node)) {
+	if (node == stop)
+	    keep = 0;
+	if (*(char *)getdata(node)) {
+	    remnulargs(getdata(node));
+	    if (unset(IGNOREBRACES) && !(flags & PF_SINGLE)) {
+		if (!keep)
+		    stop = nextnode(node);
+		while (hasbraces(getdata(node))) {
+		    keep = 1;
+		    xpandbraces(list, &node);
+		}
+	    }
+	    if (unset(SHFILEEXPANSION))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	} else if (!(flags & PF_SINGLE) && !keep)
+	    uremnode(list, node);
+	if (errflag) {
+	    unqueue_signals();
+	    return;
+	}
+}
+unqueue_signals();
+}
+/**/
+static LinkNode
+stringsubst(LinkList list, LinkNode node, int ssub, int asssub)
+{
+int qt;
+char *str3 = (char *)getdata(node);
+char *str  = str3, c;
+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 (c == Inbrack) {
+		/* $[...] */
+		char *str2 = str;
+		str2++;
+		if (skipparens(Inbrack, Outbrack, &str2)) {
+		    zerr("closing bracket missing", NULL, 0);
+		    return NULL;
+		}
+		str2[-1] = *str = '\0';
+		str = arithsubst(str + 2, &str3, str2);
+		setdata(node, (void *) str3);
+		continue;
+	    } else if (c == Snull) {
+		str = getkeystring(str, NULL, 4, NULL);
+		continue;
+	    } else {
+		node = paramsubst(list, node, &str, qt, ssub);
+		if (errflag || !node)
+		    return NULL;
+		str3 = (char *)getdata(node);
+		continue;
+	    }
+	} else if ((qt = c == Qtick) || (c == Tick ? (mult_isarr = 1) : 0))
+	  comsub: {
+	    LinkList pl;
+	    char *s, *str2 = str;
+	    char endchar;
+	    int l1, l2;
+	    if (c == Inpar) {
+		endchar = Outpar;
+		str[-1] = '\0';
+#ifdef DEBUG
+		if (skipparens(Inpar, Outpar, &str))
+		    dputs("BUG: parse error in command substitution");
+#else
+		skipparens(Inpar, Outpar, &str);
+#endif
+		str--;
+	    } else {
+		endchar = c;
+		*str = '\0';
+		while (*++str != endchar)
+		    DPUTS(!*str, "BUG: parse error in command substitution");
+	    }
+	    *str++ = '\0';
+	    if (endchar == Outpar && str2[1] == '(' && str[-2] == ')') {
+		/* Math substitution of the form $((...)) */
+		str[-2] = '\0';
+		str = arithsubst(str2 + 2, &str3, str);
+		setdata(node, (void *) str3);
+		continue;
+	    }
+	    /* It is a command substitution, which will be parsed again   *
+	     * by the lexer, so we untokenize it first, but we cannot use *
+	     * untokenize() since in the case of `...` some Bnulls should *
+	     * 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 ${(e)~...} substitution.       */
+	    for (str = str2; (c = *++str); )
+		if (itok(c) && c != Nularg &&
+		    !(endchar != Outpar && c == Bnull &&
+		      (str[1] == '$' || str[1] == '\\' || str[1] == '`' ||
+		       (qt && str[1] == '"'))))
+		    *str = ztokens[c - Pound];
+	    str++;
+	    if (!(pl = getoutput(str2 + 1, qt || ssub))) {
+		zerr("parse error in command substitution", NULL, 0);
+		return NULL;
+	    }
+	    if (endchar == Outpar)
+		str2--;
+	    if (!(s = (char *) ugetnode(pl))) {
+		str = strcpy(str2, str);
+		continue;
+	    }
+	    if (!qt && ssub && isset(GLOBSUBST))
+		shtokenize(s);
+	    l1 = str2 - str3;
+	    l2 = strlen(s);
+	    if (nonempty(pl)) {
+		LinkNode n = lastnode(pl);
+		str2 = (char *) hcalloc(l1 + l2 + 1);
+		strcpy(str2, str3);
+		strcpy(str2 + l1, s);
+		setdata(node, str2);
+		insertlinklist(pl, node, list);
+		s = (char *) getdata(node = n);
+		l1 = 0;
+		l2 = strlen(s);
+	    }
+	    str2 = (char *) hcalloc(l1 + l2 + strlen(str) + 1);
+	    if (l1)
+		strcpy(str2, str3);
+	    strcpy(str2 + l1, s);
+	    str = strcpy(str2 + l1 + l2, str);
+	    str3 = str2;
+	    setdata(node, str3);
+	    continue;
+	} else if (asssub && ((c == '=') || c == Equals) && str != str3) {
+	    /*
+	     * We are in a normal argument which looks like an assignment
+	     * and is to be treated like one, with no word splitting.
+	     */
+	    ssub = 1;
+	}
+	str++;
+}
+return errflag ? NULL : node;
+}
+/*
+* Simplified version of the prefork/singsub processing where
+* we only do substitutions appropriate to quoting.  Currently
+* this means only the expansions in $'....'.  This is used
+* for the end tag for here documents.  As we are not doing
+* `...` expansions, we just use those for quoting.  However,
+* they stay in the text.  This is weird, but that's not
+* my fault.
+*
+* The remnulargs() makes this consistent with the other forms
+* of substitution, indicating that quotes have been fully
+* processed.
+*/
+/**/
+void
+quotesubst(char *str)
+{
+char *s = str;
+while (*s) {
+	if (*s == String && s[1] == Snull) {
+	    s = getkeystring(s, NULL, 4, NULL);
+	} else {
+	    s++;
+	}
+}
+remnulargs(str);
+}
+/**/
+mod_export void
+globlist(LinkList list, int nountok)
+{
+LinkNode node, next;
+badcshglob = 0;
+for (node = firstnode(list); !errflag && node; node = next) {
+	next = nextnode(node);
+	zglob(list, node, nountok);
+}
+if (badcshglob == 1)
+	zerr("no match", NULL, 0);
+}
+/* perform substitution on a single word */
+/**/
+mod_export void
+singsub(char **s)
+{
+int omi = mult_isarr;
+local_list1(foo);
+init_list1(foo, *s);
+prefork(&foo, PF_SINGLE);
+mult_isarr = omi;
+if (errflag)
+	return;
+*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 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.                                           *
+* 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, UNUSED(char *sep))
+{
+int l, omi = mult_isarr;
+char **r, **p;
+local_list1(foo);
+#ifdef __SYMBIAN32__
+	sep=sep;
+#endif
+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))) {
+	p = r = hcalloc((l + 1) * sizeof(char*));
+	while (nonempty(&foo))
+	    *p++ = (char *)ugetnode(&foo);
+	*p = NULL;
+	/*
+	 * This is the most obscure way of deciding whether a value is
+	 * an array it would be possible to imagine.  It seems to result
+	 * partly because we don't pass down the qt and ssub flags from
+	 * paramsubst() through prefork() properly, partly because we
+	 * don't tidy up to get back the return type from multsub we
+	 * need properly.  The crux of neatening this up is to get rid
+	 * of the following test.
+	 */
+	if (a && mult_isarr) {
+	    *a = r;
+	    *isarr = SCANPM_MATCHMANY;
+	    mult_isarr = omi;
+	    return 0;
+	}
+	*s = sepjoin(r, NULL, 1);
+	mult_isarr = omi;
+	if (isarr)
+	    *isarr = 0;
+	return 0;
+}
+if (l)
+	*s = (char *) ugetnode(&foo);
+else
+	*s = dupstring("");
+if (isarr)
+	*isarr = 0;
+mult_isarr = omi;
+return !l;
+}
+/*
+* ~, = subs: assign & PF_TYPESET => typeset or magic equals
+*            assign & PF_ASSIGN => normal assignment
+*/
+/**/
+mod_export void
+filesub(char **namptr, int assign)
+{
+char *eql = NULL, *sub = NULL, *str, *ptr;
+int len;
+filesubstr(namptr, assign);
+if (!assign)
+	return;
+if (assign & PF_TYPESET) {
+	if ((*namptr)[1] && (eql = sub = strchr(*namptr + 1, Equals))) {
+	    str = sub + 1;
+	    if ((sub[1] == Tilde || sub[1] == Equals) && filesubstr(&str, assign)) {
+		sub[1] = '\0';
+		*namptr = dyncat(*namptr, str);
+	    }
+	} else
+	    return;
+}
+ptr = *namptr;
+while ((sub = strchr(ptr, ':'))) {
+	str = sub + 1;
+	len = sub - *namptr;
+	if (sub > eql &&
+	    (sub[1] == Tilde || sub[1] == Equals) &&
+	    filesubstr(&str, assign)) {
+	    sub[1] = '\0';
+	    *namptr = dyncat(*namptr, str);
+	}
+	ptr = *namptr + len + 1;
+}
+}
+/**/
+mod_export int
+filesubstr(char **namptr, int assign)
+{
+#define isend(c) ( !(c) || (c)=='/' || (c)==Inpar || (assign && (c)==':') )
+#define isend2(c) ( !(c) || (c)==Inpar || (assign && (c)==':') )
+char *str = *namptr;
+if (*str == Tilde && str[1] != '=' && str[1] != Equals) {
+	char *ptr;
+	int val;
+	val = zstrtol(str + 1, &ptr, 10);
+	if (isend(str[1])) {   /* ~ */
+	    *namptr = dyncat(home, str + 1);
+	    return 1;
+	} else if (str[1] == '+' && isend(str[2])) {   /* ~+ */
+	    *namptr = dyncat(pwd, str + 2);
+	    return 1;
+	} else if (str[1] == '-' && isend(str[2])) {   /* ~- */
+	    char *tmp;
+	    *namptr = dyncat((tmp = oldpwd) ? tmp : pwd, str + 2);
+	    return 1;
+	} else if (!inblank(str[1]) && isend(*ptr) &&
+		   (!idigit(str[1]) || (ptr - str < 4))) {
+	    char *ds;
+	    if (val < 0)
+		val = -val;
+	    ds = dstackent(str[1], val);
+	    if (!ds)
+		return 0;
+	    *namptr = dyncat(ds, ptr);
+	    return 1;
+	} else if (iuser(str[1])) {   /* ~foo */
+	    char *ptr, *hom, save;
+	    for (ptr = ++str; *ptr && iuser(*ptr); ptr++);
+	    save = *ptr;
+	    if (!isend(save))
+		return 0;
+	    *ptr = 0;
+	    if (!(hom = getnameddir(str))) {
+		if (isset(NOMATCH))
+		    zerr("no such user or named directory: %s", str, 0);
+		*ptr = save;
+		return 0;
+	    }
+	    *ptr = save;
+	    *namptr = dyncat(hom, ptr);
+	    return 1;
+	}
+} else if (*str == Equals && isset(EQUALS) && str[1]) {   /* =foo */
+	char sav, *pp, *cnam;
+	for (pp = str + 1; !isend2(*pp); pp++);
+	sav = *pp;
+	*pp = 0;
+	if (!(cnam = findcmd(str + 1, 1))) {
+	    if (isset(NOMATCH))
+		zerr("%s not found", str + 1, 0);
+	    return 0;
+	}
+	*namptr = dupstring(cnam);
+	if (sav) {
+	    *pp = sav;
+	    *namptr = dyncat(*namptr, pp);
+	}
+	return 1;
+}
+return 0;
+#undef isend
+#undef isend2
+}
+/**/
+static char *
+strcatsub(char **d, char *pb, char *pe, char *src, int l, char *s, int glbsub,
+	  int copied)
+{
+char *dest;
+int pl = pe - pb;
+if (!pl && (!s || !*s)) {
+	*d = dest = (copied ? src : dupstring(src));
+	if (glbsub)
+	    shtokenize(dest);
+} else {
+	*d = dest = hcalloc(pl + l + (s ? strlen(s) : 0) + 1);
+	strncpy(dest, pb, pl);
+	dest += pl;
+	strcpy(dest, src);
+	if (glbsub)
+	    shtokenize(dest);
+	dest += l;
+	if (s)
+	    strcpy(dest, s);
+}
+return dest;
+}
+typedef int (*CompareFn) _((const void *, const void *));
+/**/
+int
+strpcmp(const void *a, const void *b)
+{
+#ifdef HAVE_STRCOLL
+return strcoll(*(char **)a, *(char **)b);
+#else
+return strcmp(*(char **)a, *(char **)b);
+#endif
+}
+/**/
+int
+invstrpcmp(const void *a, const void *b)
+{
+#ifdef HAVE_STRCOLL
+return -strcoll(*(char **)a, *(char **)b);
+#else
+return -strcmp(*(char **)a, *(char **)b);
+#endif
+}
+/**/
+int
+cstrpcmp(const void *a, const void *b)
+{
+#ifdef HAVE_STRCOLL
+VARARR(char, c, strlen(*(char **) a) + 1);
+VARARR(char, d, strlen(*(char **) b) + 1);
+char *s, *t;
+int   cmp;
+for (s = *(char **) a, t = c; (*t++ = tulower(*s++)););
+for (s = *(char **) b, t = d; (*t++ = tulower(*s++)););
+cmp = strcoll(c, d);
+return cmp;
+#else
+char *c = *(char **)a, *d = *(char **)b;
+for (; *c && tulower(*c) == tulower(*d); c++, d++);
+return (int)STOUC(tulower(*c)) - (int)STOUC(tulower(*d));
+#endif
+}
+/**/
+int
+invcstrpcmp(const void *a, const void *b)
+{
+#ifdef HAVE_STRCOLL
+VARARR(char, c, strlen(*(char **) a) + 1);
+VARARR(char, d, strlen(*(char **) b) + 1);
+char *s, *t;
+int   cmp;
+for (s = *(char **) a, t = c; (*t++ = tulower(*s++)););
+for (s = *(char **) b, t = d; (*t++ = tulower(*s++)););
+cmp = strcoll(c, d);
+return -cmp;
+#else
+char *c = *(char **)a, *d = *(char **)b;
+for (; *c && tulower(*c) == tulower(*d); c++, d++);
+return (int)STOUC(tulower(*d)) - (int)STOUC(tulower(*c));
+#endif
+}
+/**/
+int
+nstrpcmp(const void *a, const void *b)
+{
+char *c = *(char **)a, *d = *(char **)b;
+int cmp;
+#ifdef HAVE_STRCOLL
+cmp = strcoll(c, d);
+#endif
+for (; *c == *d && *c; c++, d++);
+#ifndef HAVE_STRCOLL
+cmp = (int)STOUC(*c) - (int)STOUC(*d);
+#endif
+if (idigit(*c) || idigit(*d)) {
+	for (; c > *(char **)a && idigit(c[-1]); c--, d--);
+	if (idigit(*c) && idigit(*d)) {
+	    while (*c == '0')
+		c++;
+	    while (*d == '0')
+		d++;
+	    for (; idigit(*c) && *c == *d; c++, d++);
+	    if (idigit(*c) || idigit(*d)) {
+		cmp = (int)STOUC(*c) - (int)STOUC(*d);
+		while (idigit(*c) && idigit(*d))
+		    c++, d++;
+		if (idigit(*c) && !idigit(*d))
+		    return 1;
+		if (idigit(*d) && !idigit(*c))
+		    return -1;
+	    }
+	}
+}
+return cmp;
+}
+/**/
+int
+invnstrpcmp(const void *a, const void *b)
+{
+return -nstrpcmp(a, b);
+}
+/**/
+int
+instrpcmp(const void *a, const void *b)
+{
+VARARR(char, c, strlen(*(char **) a) + 1);
+VARARR(char, d, strlen(*(char **) b) + 1);
+char **e = (char **)&c;
+char **f = (char **)&d;
+char *s, *t;
+for (s = *(char **) a, t = c; (*t++ = tulower(*s++)););
+for (s = *(char **) b, t = d; (*t++ = tulower(*s++)););
+return nstrpcmp(&e, &f);
+}
+/**/
+int
+invinstrpcmp(const void *a, const void *b)
+{
+return -instrpcmp(a, b);
+}
+/**/
+static char *
+dopadding(char *str, int prenum, int postnum, char *preone, char *postone, char *premul, char *postmul)
+{
+char def[3], *ret, *t, *r;
+int ls, ls2, lpreone, lpostone, lpremul, lpostmul, lr, f, m, c, cc;
+def[0] = *ifs ? *ifs : ' ';
+def[1] = *ifs == Meta ? ifs[1] ^ 32 : '\0';
+def[2] = '\0';
+if (preone && !*preone)
+	preone = def;
+if (postone && !*postone)
+	postone = def;
+if (!premul || !*premul)
+	premul = def;
+if (!postmul || !*postmul)
+	postmul = def;
+ls = strlen(str);
+lpreone = preone ? strlen(preone) : 0;
+lpostone = postone ? strlen(postone) : 0;
+lpremul = strlen(premul);
+lpostmul = strlen(postmul);
+lr = prenum + postnum;
+if (lr == ls)
+	return str;
+r = ret = (char *)zhalloc(lr + 1);
+if (prenum) {
+	if (postnum) {
+	    ls2 = ls / 2;
+	    f = prenum - ls2;
+	    if (f <= 0)
+		for (str -= f, c = prenum; c--; *r++ = *str++);
+	    else {
+		if (f <= lpreone)
+		    for (c = f, t = preone + lpreone - f; c--; *r++ = *t++);
+		else {
+		    f -= lpreone;
+		    if ((m = f % lpremul))
+			for (c = m, t = premul + lpremul - m; c--; *r++ = *t++);
+		    for (cc = f / lpremul; cc--;)
+			for (c = lpremul, t = premul; c--; *r++ = *t++);
+		    for (c = lpreone; c--; *r++ = *preone++);
+		}
+		for (c = ls2; c--; *r++ = *str++);
+	    }
+	    ls2 = ls - ls2;
+	    f = postnum - ls2;
+	    if (f <= 0)
+		for (c = postnum; c--; *r++ = *str++);
+	    else {
+		for (c = ls2; c--; *r++ = *str++);
+		if (f <= lpostone)
+		    for (c = f; c--; *r++ = *postone++);
+		else {
+		    f -= lpostone;
+		    for (c = lpostone; c--; *r++ = *postone++);
+		    for (cc = f / lpostmul; cc--;)
+			for (c = lpostmul, t = postmul; c--; *r++ = *t++);
+		    if ((m = f % lpostmul))
+			for (; m--; *r++ = *postmul++);
+		}
+	    }
+	} else {
+	    f = prenum - ls;
+	    if (f <= 0)
+		for (c = prenum, str -= f; c--; *r++ = *str++);
+	    else {
+		if (f <= lpreone)
+		    for (c = f, t = preone + lpreone - f; c--; *r++ = *t++);
+		else {
+		    f -= lpreone;
+		    if ((m = f % lpremul))
+			for (c = m, t = premul + lpremul - m; c--; *r++ = *t++);
+		    for (cc = f / lpremul; cc--;)
+			for (c = lpremul, t = premul; c--; *r++ = *t++);
+		    for (c = lpreone; c--; *r++ = *preone++);
+		}
+		for (c = ls; c--; *r++ = *str++);
+	    }
+	}
+} else if (postnum) {
+	f = postnum - ls;
+	if (f <= 0)
+	    for (c = postnum; c--; *r++ = *str++);
+	else {
+	    for (c = ls; c--; *r++ = *str++);
+	    if (f <= lpostone)
+		for (c = f; c--; *r++ = *postone++);
+	    else {
+		f -= lpostone;
+		for (c = lpostone; c--; *r++ = *postone++);
+		for (cc = f / lpostmul; cc--;)
+		    for (c = lpostmul, t = postmul; c--; *r++ = *t++);
+		if ((m = f % lpostmul))
+		    for (; m--; *r++ = *postmul++);
+	    }
+	}
+}
+*r = '\0';
+return ret;
+}
+/**/
+char *
+get_strarg(char *s)
+{
+char t = *s++;
+if (!t)
+	return s - 1;
+switch (t) {
+case '(':
+	t = ')';
+	break;
+case '[':
+	t = ']';
+	break;
+case '{':
+	t = '}';
+	break;
+case '<':
+	t = '>';
+	break;
+case Inpar:
+	t = Outpar;
+	break;
+case Inang:
+	t = Outang;
+	break;
+case Inbrace:
+	t = Outbrace;
+	break;
+case Inbrack:
+	t = Outbrack;
+	break;
+}
+while (*s && *s != t)
+	s++;
+return s;
+}
+/**/
+static int
+get_intarg(char **s)
+{
+char *t = get_strarg(*s + 1);
+char *p, sav;
+zlong ret;
+if (!*t)
+	return -1;
+sav = *t;
+*t = '\0';
+p = dupstring(*s + 2);
+*s = t;
+*t = sav;
+if (parsestr(p))
+	return -1;
+singsub(&p);
+if (errflag)
+	return -1;
+ret = mathevali(p);
+if (errflag)
+	return -1;
+if (ret < 0)
+	ret = -ret;
+return ret < 0 ? -ret : ret;
+}
+/* Parsing for the (e) flag. */
+static int
+subst_parse_str(char **sp, int single, int err)
+{
+char *s;
+*sp = s = dupstring(*sp);
+if (!(err ? parsestr(s) : parsestrnoerr(s))) {
+	if (!single) {
+int qt = 0;
+	    for (; *s; s++)
+		if (!qt) {
+		    if (*s == Qstring)
+			*s = String;
+		    else if (*s == Qtick)
+			*s = Tick;
+} else if (*s == Dnull)
+qt = !qt;
+	}
+	return 0;
+}
+return 1;
+}
+/* parameter substitution */
+#define	isstring(c) ((c) == '$' || (char)(c) == String || (char)(c) == Qstring)
+#define isbrack(c)  ((c) == '[' || (char)(c) == Inbrack)
+/*
+* Given a linked list l with node n, perform parameter substitution
+* starting from *str.  Return the node with the substitutuion performed
+* or NULL if it failed.
+*
+* If qt is true, the `$' was quoted.  TODO: why can't we just look
+* to see if the first character was String or Qstring?
+*
+* If ssub is true, we are being called via singsubst(), which means
+* the result will be a single word.  TODO: can we generate the
+* single word at the end?  TODO: if not, or maybe in any case,
+* can we pass down the ssub flag from prefork with the other flags
+* instead of pushing it into different arguments?  (How exactly
+* to qt and ssub differ?  Are both necessary, if so is there some
+* better way of separating the two?)
+*/
+/**/
+LinkNode
+paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
+{
+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 */
+/*
+* There are far too many flags.  They need to be grouped
+* together into some structure which ties them to where they
+* came from.
+*
+* Some flags have a an obscure relationship to their effect which
+* depends on incrementing them to particular values in particular
+* ways.
+*/
+/*
+* Whether the value is an array (in aval) or not (in val).  There's
+* a movement from storing the value in the stuff read from the
+* parameter (the value v) to storing them in val and aval.
+* However, sometimes you find v reappearing temporarily.
+*
+* The values -1 and 2 are special to isarr.  It looks like 2 is
+* some kind of an internal flag to do with whether the array's been
+* copied, in which case I don't know why we don't use the copied
+* flag, but they do both occur close together so they presumably
+* have different effects.  The value -1 is isued to force us to
+* keep an empty array.  It's tested in the YUK chunk (I mean the
+* one explicitly marked as such).
+*/
+int isarr = 0;
+/*
+* This is just the setting of the option except we need to
+* take account of ^ and ^^.
+*/
+int plan9 = isset(RCEXPANDPARAM);
+/*
+* Likwise, but with ~ and ~~.  Also, we turn it off later
+* on if qt is passed down.
+*/
+int globsubst = isset(GLOBSUBST);
+/*
+* Indicates ${#pm}, massaged by whichlen which is set by
+* the (c), (w), and (W) flags to indicate how we take the length.
+*/
+int getlen = 0;
+int whichlen = 0;
+/*
+* Indicates ${+pm}: a simple boolean for once.
+*/
+int chkset = 0;
+/*
+* Indicates we have tried to get a value in v but that was
+* unset.  I don't quite understand why (v == NULL) isn't
+* good enough, but there are places where we seem to need
+* to second guess whether a value is a real value or not.
+*/
+int vunset = 0;
+/*
+* Indicates (t) flag, i.e. print out types.  The code for
+* this actually isn't too horrifically inbred compared with
+* that for (P).
+*/
+int wantt = 0;
+/*
+* Indicates spliting a string into an array.  There aren't
+* actually that many special cases for this --- which may
+* be why it doesn't work properly; we split in some cases
+* where we shouldn't, in particular on the multsubs for
+* handling embedded values for ${...=...} and the like.
+*/
+int spbreak = isset(SHWORDSPLIT) && !ssub && !qt;
+/* Scalar and array value, see isarr above */
+char *val = NULL, **aval = NULL;
+/*
+* Padding based on setting in parameter rather than substitution
+* flags.  This is only used locally.
+*/
+unsigned int fwidth = 0;
+/*
+* vbuf and v are both used to retrieve parameter values; this
+* is a kludge, we pass down vbuf and it may or may not return v.
+*/
+struct value vbuf;
+Value v = NULL;
+/*
+* This expressive name refers to the set of flags which
+* is applied to matching for #, %, / and their doubled variants:
+* (M), (R), (B), (E), (N), (S).
+*/
+int flags = 0;
+/* Value from (I) flag, used for ditto. */
+int flnum = 0;
+/*
+* sortit is an obscure combination of the settings for (o), (O),
+* (i) and (n). casind is (i) and numord is (n); these are
+* separate so we can have fun doing the obscure combinatorics later.
+* indord is the (a) flag, which for consistency doesn't get
+* combined into sortit.
+*/
+int sortit = 0, casind = 0, numord = 0, indord = 0;
+/* (u): straightforward. */
+int unique = 0;
+/* combination of (L), (U) and (C) flags. */
+int casmod = 0;
+/*
+* quotemod says we are doing either (q) (positive), (Q) (negative)
+* or not (0).  quotetype counts the q's for the first case.
+* quoterr is simply (X) but gets passed around a lot because the
+* combination (eX) needs it.
+*/
+int quotemod = 0, quotetype = 0, quoteerr = 0;
+/*
+* (V) flag: fairly straightforward, except that as with so
+* many flags it's not easy to decide where to put it in the order.
+*/
+int visiblemod = 0;
+/*
+* The (z) flag, nothing to do with SH_WORD_SPLIT which is tied
+* spbreak, see above; fairly straighforward in use but c.f.
+* the comment for visiblemod.
+*/
+int shsplit = 0;
+/*
+* The separator from (j) and (s) respectively, or (F) and (f)
+* respectively (hardwired to "\n" in that case).  Slightly
+* confusingly also used for ${#pm}, thought that's at least
+* documented in the manual
+*/
+char *sep = NULL, *spsep = NULL;
+/*
+* Padding strings.  The left and right padding strings which
+* are repeated, then the ones which only occur once, for
+* the (l) and (r) flags.
+*/
+char *premul = NULL, *postmul = NULL, *preone = NULL, *postone = NULL;
+/* Replacement string for /orig/repl and //orig/repl */
+char *replstr = NULL;
+/* The numbers for (l) and (r) */
+zlong prenum = 0, postnum = 0;
+/*
+* Whether the value has been copied.  Optimisation:  if we
+* are modifying an expression, we only need to copy it the
+* first time, and if we don't modify it we can just use the
+* value from the parameter or input.
+*/
+int copied = 0;
+/*
+* The (A) flag for array assignment, with consequences for
+* splitting and joining; (AA) gives arrasg == 2 for associative
+* arrays.
+*/
+int arrasg = 0;
+/*
+* The (e) flag.  As we need to do extra work not quite
+* at the end, the effect of this is kludged in in several places.
+*/
+int eval = 0;
+/*
+* The (P) flag.  This interacts a bit obscurely with whether
+* or not we are dealing with a sub expression (subexp).
+*/
+int aspar = 0;
+/*
+* The (%) flag, c.f. visiblemod again.
+*/
+int presc = 0;
+/*
+* The (@) flag; interacts obscurely with qt and isarr.
+* This is one of the things that decides whether multsub
+* will produce an array, but in an extremely indirect fashion.
+*/
+int nojoin = 0;
+/*
+* != 0 means ${...}, otherwise $...  What works without braces
+* is largely a historical artefact (everything works with braces,
+* I sincerely hope).
+*/
+char inbrace = 0;
+/*
+* Use for the (k) flag.  Goes down into the parameter code,
+* sometimes.
+*/
+char hkeys = 0;
+/*
+* Used for the (v) flag, ditto.  Not quite sure why they're
+* separate, but the tradition seems to be that things only
+* get combined when that makes the result more obscure rather
+* than less.
+*/
+char hvals = 0;
+/*
+* Whether we had to evaluate a subexpression, i.e. an
+* internal ${...} or $(...) or plain $pm.  We almost don't
+* need to remember this (which would be neater), but the (P)
+* flag means the subexp and !subexp code is obscurely combined,
+* and the argument passing to fetchvalue has another kludge.
+*/
+int subexp;
+*s++ = '\0';
+/*
+* Nothing to do unless the character following the $ is
+* something we recognise.
+*
+* Shouldn't this be a table or something?  We test for all
+* these later on, too.
+*/
+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(c == '{', "BUG: inbrace == '{' in paramsubst()");
+/*
+* Extra processing if there is an opening brace: mostly
+* flags in parentheses, but also one ksh hack.
+*/
+if (c == Inbrace) {
+	inbrace = 1;
+	s++;
+	/*
+	 * In ksh emulation a leading `!' is a special flag working
+	 * sort of like our (k).
+	 * TODO: this is one of very few cases tied directly to
+	 * the emulation mode rather than an option.  Since ksh
+	 * doesn't have parameter flags it might be neater to
+	 * handle this with the ^, =, ~ stuff, below.
+	 */
+	if ((c = *s) == '!' && s[1] != Outbrace && emulation == EMULATE_KSH) {
+	    hkeys = SCANPM_WANTKEYS;
+	    s++;
+	} else if (c == '(' || c == Inpar) {
+	    char *t, sav;
+	    int tt = 0;
+	    zlong num;
+	    /*
+	     * The (p) flag is (uniquely) only remembered within
+	     * this block.  It says we do print-style handling
+	     * on the values for flags, but only on those.
+	     * This explains the ghastly macro, but why can't it
+	     * be a function?  UNTOK_AND_ESCAPE is defined
+	     * so that the argument must be an lvalue.
+	     */
+	    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) {\
+		    X = getkeystring(X, &klen, 3, NULL);\
+		    X = metafy(X, klen, META_HREALLOC);\
+		}\
+	    }
+	    for (s++; (c = *s) != ')' && c != Outpar; s++, tt = 0) {
+		switch (c) {
+		case ')':
+		case Outpar:
+		    break;
+		case 'A':
+		    ++arrasg;
+		    break;
+		case '@':
+		    nojoin = 1;
+		    break;
+		case 'M':
+		    flags |= SUB_MATCH;
+		    break;
+		case 'R':
+		    flags |= SUB_REST;
+		    break;
+		case 'B':
+		    flags |= SUB_BIND;
+		    break;
+		case 'E':
+		    flags |= SUB_EIND;
+		    break;
+		case 'N':
+		    flags |= SUB_LEN;
+		    break;
+		case 'S':
+		    flags |= SUB_SUBSTR;
+		    break;
+		case 'I':
+		    flnum = get_intarg(&s);
+		    if (flnum < 0)
+			goto flagerr;
+		    break;
+		case 'L':
+		    casmod = 2;
+		    break;
+		case 'U':
+		    casmod = 1;
+		    break;
+		case 'C':
+		    casmod = 3;
+		    break;
+		case 'o':
+		    sortit = 1;
+		    break;
+		case 'O':
+		    sortit = 2;
+		    break;
+		case 'i':
+		    casind = 1;
+		    break;
+		case 'n':
+		    numord = 1;
+		    break;
+		case 'a':
+		    indord = 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;
+		    break;
+		case 'w':
+		    whichlen = 2;
+		    break;
+		case 'W':
+		    whichlen = 3;
+		    break;
+		case 'f':
+		    spsep = "\n";
+		    break;
+		case 'F':
+		    sep = "\n";
+		    break;
+		case 's':
+		    tt = 1;
+		/* fall through */
+		case 'j':
+		    t = get_strarg(++s);
+		    if (*t) {
+			sav = *t;
+			*t = '\0';
+			if (tt)
+			    UNTOK_AND_ESCAPE(spsep)
+			else
+			    UNTOK_AND_ESCAPE(sep)
+			*t = sav;
+			s = t;
+		    } else
+			goto flagerr;
+		    break;
+		case 'l':
+		    tt = 1;
+		/* fall through */
+		case 'r':
+		    sav = s[1];
+		    num = get_intarg(&s);
+		    if (num < 0)
+			goto flagerr;
+		    if (tt)
+			prenum = num;
+		    else
+			postnum = num;
+		    if (UNTOK(s[1]) != UNTOK(sav))
+			break;
+		    t = get_strarg(++s);
+		    if (!*t)
+			goto flagerr;
+		    sav = *t;
+		    *t = '\0';
+		    if (tt)
+			UNTOK_AND_ESCAPE(premul)
+		    else
+			UNTOK_AND_ESCAPE(postmul)
+		    *t = sav;
+		    sav = *s;
+		    s = t + 1;
+		    if (UNTOK(*s) != UNTOK(sav)) {
+			s--;
+			break;
+		    }
+		    t = get_strarg(s);
+		    if (!*t)
+			goto flagerr;
+		    sav = *t;
+		    *t = '\0';
+		    if (tt)
+			UNTOK_AND_ESCAPE(preone)
+		    else
+			UNTOK_AND_ESCAPE(postone)
+		    *t = sav;
+		    s = t;
+		    break;
+		case 'p':
+		    escapes = 1;
+		    break;
+		case 'k':
+		    hkeys = SCANPM_WANTKEYS;
+		    break;
+		case 'v':
+		    hvals = SCANPM_WANTVALS;
+		    break;
+		case 't':
+		    wantt = 1;
+		    break;
+		case '%':
+		    presc++;
+		    break;
+		case 'z':
+		    shsplit = 1;
+		    break;
+		case 'u':
+		    unique = 1;
+		    break;
+		default:
+		  flagerr:
+		    zerr("error in flags", NULL, 0);
+		    return NULL;
+		}
+	    }
+	    s++;
+	}
+}
+/* Sort is done by indexing on sortit-1:
+*   bit 1: ascending (o)/descending (O)
+*   bit 2: case sensitive/independent (i)
+*   bit 3: strict order/numeric (n)
+* unless indord (a) is set set, in which case only test for
+* descending by assuming only (O) is possible (not verified).
+*/
+if (sortit)
+	sortit += (casind << 1) + (numord << 2);
+/*
+* premul, postmul specify the padding character to be used
+* multiple times with the (l) and (r) flags respectively.
+*/
+if (!premul)
+	premul = " ";
+if (!postmul)
+	postmul = " ";
+/*
+* Look for special unparenthesised flags.
+* TODO: could make these able to appear inside parentheses, too,
+* i.e. ${(^)...} etc.
+*/
+for (;;) {
+	if ((c = *s) == '^' || c == Hat) {
+	    /* RC_EXPAND_PARAM on or off (doubled )*/
+	    if ((c = *++s) == '^' || c == Hat) {
+		plan9 = 0;
+		s++;
+	    } else
+		plan9 = 1;
+	} else if ((c = *s) == '=' || c == Equals) {
+	    /* SH_WORD_SPLIT on or off (doubled). spbreak = 2 means force */
+	    if ((c = *++s) == '=' || c == Equals) {
+		spbreak = 0;
+		s++;
+	    } else
+		spbreak = 2;
+	} 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++;
+	    /*
+	     * Return the length of the parameter.
+	     * getlen can be more than 1 to indicate characters (2),
+	     * words ignoring multiple delimiters (3), words taking
+	     * account of multiple delimiters.  delimiter is in
+	     * spsep, NULL means $IFS.
+	     */
+	} else if (c == '~' || c == Tilde) {
+	    /* GLOB_SUBST on or off (doubled) */
+	    if ((c = *++s) == '~' || c == Tilde) {
+		globsubst = 0;
+		s++;
+	    } else
+		globsubst = 1;
+	} else if (c == '+') {
+	    /*
+	     * Return whether indicated parameter is set.
+	     * Try to handle this when parameter is named
+	     * by (P) (second part of test).
+	     */
+	    if (iident(s[1]) || (aspar && isstring(s[1]) &&
+				 (s[2] == Inbrace || s[2] == Inpar)))
+		chkset = 1, s++;
+	    else if (!inbrace) {
+		/* Special case for `$+' on its own --- leave unmodified */
+		*aptr = '$';
+		*str = aptr + 1;
+		return n;
+	    } else {
+		zerr("bad substitution", NULL, 0);
+		return NULL;
+	    }
+	} else if (inbrace && INULL(*s)) {
+	    /*
+	     * Handles things like ${(f)"$(<file)"} by skipping
+	     * the double quotes.  We don't need to know what was
+	     * actually there; the presence of a String or Qstring
+	     * is good enough.
+	     */
+	    s++;
+	} else
+	    break;
+}
+/* Don't activate special pattern characters if inside quotes */
+globsubst = globsubst && !qt;
+/*
+* At this point, we usually expect a parameter name.
+* However, there may be a nested ${...} or $(...).
+* These say that the parameter itself is somewhere inside,
+* or that there isn't a parameter and we will get the values
+* from a command substitution itself.  In either case,
+* the current instance of paramsubst() doesn't fetch a value,
+* it just operates on what gets passed up.
+* (The first ought to have been {...}, reserving ${...}
+* for substituting a value at that point, but it's too late now.)
+*/
+idbeg = s;
+if ((subexp = (inbrace && s[-1] && isstring(*s) &&
+		   (s[1] == Inbrace || s[1] == Inpar)))) {
+	int sav;
+	int quoted = *s == Qstring;
+	val = s++;
+	skipparens(*s, *s == Inpar ? Outpar : Outbrace, &s);
+	sav = *s;
+	*s = 0;
+	/*
+	 * This handles arrays.  TODO: this is not the most obscure call to
+	 * multsub() (see below) but even so it would be nicer to pass down
+	 * and back the arrayness more rationally.  In that case, we should
+	 * remove the aspar test and extract a value from an array, if
+	 * necessary, when we handle (P) lower down.
+	 */
+	if (multsub(&val, (aspar ? NULL : &aval), &isarr, NULL) && quoted) {
+	    /* Empty quoted string --- treat as null string, not elided */
+	    isarr = -1;
+	    aval = (char **) hcalloc(sizeof(char *));
+	    aspar = 0;
+	} else if (aspar)
+	    idbeg = val;
+	*s = sav;
+	/*
+	 * This tests for the second double quote in an expression
+	 * like ${(f)"$(<file)"}, compare above.
+	 */
+	while (INULL(*s))
+	    s++;
+	v = (Value) NULL;
+} else if (aspar) {
+	/*
+	 * No subexpression, but in any case the value is going
+	 * to give us the name of a parameter on which we do
+	 * our remaining processing.  In other words, this
+	 * makes ${(P)param} work like ${(P)${param}}.  (Probably
+	 * better looked at, this is the basic code for ${(P)param}
+	 * and it's been kludged into the subexp code because no
+	 * opportunity for a kludge has been neglected.)
+	 */
+	if ((v = fetchvalue(&vbuf, &s, 1, (qt ? SCANPM_DQUOTED : 0)))) {
+	    val = idbeg = getstrvalue(v);
+	    subexp = 1;
+	} else
+	    vunset = 1;
+}
+/*
+* We need to retrieve a value either if we haven't already
+* got it from a subexpression, or if the processing so
+* far has just yielded us a parameter name to be processed
+* with (P).
+*/
+if (!subexp || aspar) {
+	char *ov = val;
+	/*
+	 * Second argument: decide whether to use the subexpression or
+	 *   the string next on the line as the parameter name.
+	 * Third argument:  decide how processing for brackets
+	 *   1 means full processing
+	 *   -1 appears to mean something along the lines of
+	 *     only handle single digits and don't handle brackets.
+	 *     I *think* (but it's really only a guess) that this
+	 *     is used by the test below the wantt handling, so
+	 *     that in certain cases we handle brackets there.
+	 *   0 would apparently mean something like we know we
+	 *     should have the name of a scalar and we get cross
+	 *     if there's anything present which disagrees with that
+	 * but you will search fetchvalue() in vain for comments on this.
+	 * Fourth argument gives flags to do with keys, values, quoting,
+	 * assigning depending on context and parameter flags.
+	 *
+	 * This is the last mention of subexp, so presumably this
+	 * is what the code which makes sure subexp is set if aspar (the
+	 * (P) flag) is set.  I *think* what's going on here is the
+	 * second argument is for both input and output: with
+	 * subexp, we only want the input effect, whereas normally
+	 * we let fetchvalue set the main string pointer s to
+	 * the end of the bit it's fetched.
+	 */
+	if (!(v = fetchvalue(&vbuf, (subexp ? &ov : &s),
+			     (wantt ? -1 :
+			      ((unset(KSHARRAYS) || inbrace) ? 1 : -1)),
+			     hkeys|hvals|
+			     (arrasg ? SCANPM_ASSIGNING : 0)|
+			     (qt ? SCANPM_DQUOTED : 0))) ||
+	    (v->pm && (v->pm->flags & PM_UNSET)))
+	    vunset = 1;
+	if (wantt) {
+	    /*
+	     * Handle the (t) flag: value now becomes the type
+	     * information for the parameter.
+	     */
+	    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_HIDE)
+		    val = dyncat(val, "-hideval");
+		if (f & PM_SPECIAL)
+		    val = dyncat(val, "-special");
+		vunset = 0;
+	    } else
+		val = dupstring("");
+	    v = NULL;
+	    isarr = 0;
+	}
+}
+/*
+* We get in here two ways; either we need to convert v into
+* the local value system, or we need to get rid of brackets
+* even if there isn't a v.
+*/
+while (v || ((inbrace || (unset(KSHARRAYS) && vunset)) && isbrack(*s))) {
+	if (!v) {
+	    /*
+	     * Index applied to non-existent parameter; we may or may
+	     * not have a value to index, however.  Create a temporary
+	     * empty parameter as a trick, and index on that.  This
+	     * usually happens the second time around the loop when
+	     * we've used up the original parameter value and want to
+	     * apply a subscript to what's left.  However, it's also
+	     * possible it's got something to do with some of that murky
+	     * passing of -1's as the third argument to fetchvalue() to
+	     * inhibit bracket parsing at that stage.
+	     */
+	    Param pm;
+	    char *os = s;
+	    if (!isbrack(*s))
+		break;
+	    if (vunset) {
+		val = dupstring("");
+		isarr = 0;
+	    }
+	    pm = createparam(nulstring, isarr ? PM_ARRAY : PM_SCALAR);
+	    DPUTS(!pm, "BUG: parameter not created");
+	    if (isarr)
+		pm->u.arr = aval;
+	    else
+		pm->u.str = val;
+	    v = (Value) hcalloc(sizeof *v);
+	    v->isarr = isarr;
+	    v->pm = pm;
+	    v->end = -1;
+	    if (getindex(&s, v, qt) || s == os)
+		break;
+	}
+	/*
+	 * This is where we extract a value (we know now we have
+	 * one) into the local parameters for a scalar (val) or
+	 * array (aval) value.  TODO: move val and aval into
+	 * a structure with a discriminator.  Hope we can make
+	 * more things array values at this point and dearrayify later.
+	 * v->isarr tells us whether the stuff form down below looks
+	 * like an array.  Unlike multsub() this is probably clean
+	 * enough to keep, although possibly the parameter passing
+	 * needs reorganising.
+	 *
+	 * I think we get to discard the existing value of isarr
+	 * here because it's already been taken account of, either
+	 * in the subexp stuff or immediately above.
+	 */
+	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 {
+	    /* Value retrieved from parameter/subexpression is scalar */
+	    if (v->pm->flags & PM_ARRAY) {
+		/*
+		 * Although the value is a scalar, the parameter
+		 * itself is an array.  Presumably this is due to
+		 * being quoted, or doing single substitution or something,
+		 * TODO: we're about to do some definitely stringy
+		 * stuff, so something like this bit is probably
+		 * necessary.  However, I'd like to leave any
+		 * necessary joining of arrays until this point
+		 * to avoid the multsub() horror.
+		 */
+		int tmplen = arrlen(v->pm->gsu.a->getfn(v->pm));
+		if (v->start < 0)
+		    v->start += tmplen + v->inv;
+		if (!v->inv && (v->start >= tmplen || v->start < 0))
+		    vunset = 1;
+	    }
+	    if (!vunset) {
+		/*
+		 * There really is a value.  Apply any necessary
+		 * padding or case transformation.  Note these
+		 * are the per-parameter transformations specified
+		 * with typeset, not the per-substitution ones set
+		 * by flags.  TODO: maybe therefore this would
+		 * be more consistent if moved into getstrvalue()?
+		 * Bet that's easier said than done.
+		 */
+		val = getstrvalue(v);
+		fwidth = v->pm->width ? v->pm->width : (int)strlen(val);
+		switch (v->pm->flags & (PM_LEFT | PM_RIGHT_B | PM_RIGHT_Z)) {
+		    char *t;
+		    unsigned int t0;
+		case PM_LEFT:
+		case PM_LEFT | PM_RIGHT_Z:
+		    t = val;
+		    if (v->pm->flags & PM_RIGHT_Z)
+			while (*t == '0')
+			    t++;
+		    else
+			while (iblank(*t))
+			    t++;
+		    val = (char *) hcalloc(fwidth + 1);
+		    val[fwidth] = '\0';
+		    if ((t0 = strlen(t)) > fwidth)
+			t0 = fwidth;
+		    memset(val, ' ', fwidth);
+		    strncpy(val, t, t0);
+		    break;
+		case PM_RIGHT_B:
+		case PM_RIGHT_Z:
+		case PM_RIGHT_Z | PM_RIGHT_B:
+		    {
+			int zero = 1;
+			if (strlen(val) < fwidth) {
+			    char *valprefend = val;
+			    if (v->pm->flags & PM_RIGHT_Z) {
+				/*
+				 * This is a documented feature: when deciding
+				 * whether to pad with zeroes, ignore
+				 * leading blanks already in the value;
+				 * only look for numbers after that.
+				 * Not sure how useful this really is.
+				 * It's certainly confusing to code around.
+				 */
+				for (t = val; iblank(*t); t++)
+				    ;
+				/*
+				 * Allow padding after initial minus
+				 * for numeric variables.
+				 */
+				if ((v->pm->flags &
+				     (PM_INTEGER|PM_EFLOAT|PM_FFLOAT)) &&
+				    *t == '-')
+				    t++;
+				/*
+				 * Allow padding after initial 0x or
+				 * base# for integer variables.
+				 */
+				if (v->pm->flags & PM_INTEGER) {
+				    if (isset(CBASES) &&
+					t[0] == '0' && t[1] == 'x')
+					t += 2;
+				    else if ((valprefend = strchr(t, '#')))
+					t = valprefend + 1;
+				}
+				valprefend = t;
+				if (!*t)
+				    zero = 0;
+				else if (v->pm->flags &
+					 (PM_INTEGER|PM_EFLOAT|PM_FFLOAT)) {
+				    /* zero always OK */
+				} else if (!idigit(*t))
+				    zero = 0;
+			    }
+			    t = (char *) hcalloc(fwidth + 1);
+			    memset(t, (((v->pm->flags & PM_RIGHT_B) || !zero) ?
+				       ' ' : '0'), fwidth);
+			    /*
+			     * How can the following trigger?  We
+			     * haven't altered val or fwidth since
+			     * the last time we tested this.
+			     */
+			    if ((t0 = strlen(val)) > fwidth)
+				t0 = fwidth;
+			    /*
+			     * Copy - or 0x or base# before any padding
+			     * zeroes.
+			     */
+			    if (zero && val != valprefend) {
+				int preflen = valprefend - val;
+				memcpy(t, val, preflen);
+				strcpy(t + (fwidth - t0) + preflen,
+				       valprefend);
+			    } else
+				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;
+		}
+		switch (v->pm->flags & (PM_LOWER | PM_UPPER)) {
+		    char *t;
+		case PM_LOWER:
+		    t = val;
+		    for (; (c = *t); t++)
+			*t = tulower(c);
+		    break;
+		case PM_UPPER:
+		    t = val;
+		    for (; (c = *t); t++)
+			*t = tuupper(c);
+		    break;
+		}
+	    }
+	}
+	/*
+	 * Finished with the original parameter and its indices;
+	 * carry on looping to see if we need to do more indexing.
+	 * This means we final get rid of v in favour of val and
+	 * aval.  We could do with somehow encapsulating the bit
+	 * where we need v.
+	 */
+	v = NULL;
+	if (!inbrace)
+	    break;
+}
+/*
+* We're now past the name or subexpression; the only things
+* which can happen now are a closing brace, one of the standard
+* parameter postmodifiers, or a history-style colon-modifier.
+*
+* Again, this duplicates tests for characters we're about to
+* examine properly later on.
+*/
+if (inbrace &&
+	(c = *s) != '-' && c != '+' && c != ':' && c != '%'  && c != '/' &&
+	c != '=' && c != Equals &&
+	c != '#' && c != Pound &&
+	c != '?' && c != Quest &&
+	c != '}' && c != Outbrace) {
+	zerr("bad substitution", NULL, 0);
+	return NULL;
+}
+/*
+* Join arrays up if we're in quotes and there isn't some
+* override such as (@).
+* TODO: hmm, if we're called as part of some recursive
+* substitution do we want to delay this until we get back to
+* the top level?  Or is if there's a qt (i.e. this parameter
+* substitution is in quotes) always good enough?  Potentially
+* we may be OK by now --- all potential `@'s and subexpressions
+* have been handled, including any [@] index which comes up
+* by virture of v->isarr being set to SCANPM_ISVAR_AT which
+* is now in isarr.
+*
+* However, if we are replacing multsub() with something that
+* doesn't mangle arrays, we may need to delay this step until after
+* the foo:- or foo:= or whatever that causes that.  Note the value
+* (string or array) at this point is irrelevant if we are going to
+* be doing that.  This would mean // and stuff get applied
+* arraywise even if quoted.  That's probably wrong, so maybe
+* this just stays.
+*
+* We do a separate stage of dearrayification in the YUK chunk,
+* I think mostly because of the way we make array or scalar
+* values appear to the caller.
+*/
+if (isarr) {
+	if (nojoin)
+	    isarr = -1;
+	if (qt && !getlen && isarr > 0) {
+	    val = sepjoin(aval, sep, 1);
+	    isarr = 0;
+	}
+}
+idend = s;
+if (inbrace) {
+	/*
+	 * This is to match a closing double quote in case
+	 * we didn't have a subexpression, e.g. ${"foo"}.
+	 * This form is pointless, but logically it ought to work.
+	 */
+	while (INULL(*s))
+	    s++;
+}
+/*
+* We don't yet know whether a `:' introduces a history-style
+* colon modifier or qualifies something like ${...:=...}.
+* But if we remember the colon here it's easy to check later.
+*/
+if ((colf = *s == ':'))
+	s++;
+/* fstr is to be the text following the substitution.  If we have *
+* braces, we look for it here, else we infer it later on.        */
+fstr = s;
+if (inbrace) {
+	int bct;
+	for (bct = 1; (c = *fstr); fstr++) {
+	    if (c == Inbrace)
+		bct++;
+	    else if (c == Outbrace && !--bct)
+		break;
+	}
+	if (bct) {
+	noclosebrace:
+	    zerr("closing brace expected", NULL, 0);
+	    return NULL;
+	}
+	if (c)
+	    *fstr++ = '\0';
+}
+/* Check for ${..?..} or ${..=..} or one of those. *
+* Only works if the name is in braces.            */
+if (inbrace && ((c = *s) == '-' ||
+		    c == '+' ||
+		    c == ':' ||	/* i.e. a doubled colon */
+		    c == '=' || c == Equals ||
+		    c == '%' ||
+		    c == '#' || c == Pound ||
+		    c == '?' || c == Quest ||
+		    c == '/')) {
+	/*
+	 * Default index is 1 if no (I) or (I) gave zero.   But
+	 * why don't we set the default explicitly at the start
+	 * and massage any passed index where we set flnum anyway?
+	 */
+	if (!flnum)
+	    flnum++;
+	if (c == '%')
+	    flags |= SUB_END;
+	/* Check for ${..%%..} or ${..##..} */
+	if ((c == '%' || c == '#' || c == Pound) && c == s[1]) {
+	    s++;
+	    /* 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;
+		c = *++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.
+	     *
+	     * We used to use double backslashes to quote slashes,
+	     * but actually that was buggy and using a single backslash
+	     * is easier and more obvious.
+	     */
+	    for (ptr = s; (c = *ptr) && c != '/'; ptr++)
+	    {
+		if ((c == Bnull || c == '\\') && ptr[1])
+		{
+		    if (ptr[1] == '/')
+			chuck(ptr);
+		    else
+			ptr++;
+		}
+	    }
+	    replstr = (*ptr && ptr[1]) ? ptr+1 : "";
+	    *ptr = '\0';
+	}
+	/* See if this was ${...:-...}, ${...:=...}, etc. */
+	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]);
+	switch (s[-1]) {
+	case '+':
+	    if (vunset) {
+		val = dupstring("");
+		copied = 1;
+		isarr = 0;
+		break;
+	    }
+	    vunset = 1;
+	/* Fall Through! */
+	case '-':
+	    if (vunset) {
+		val = dupstring(s);
+		/*
+		 * This is not good enough for sh emulation!  Sh would
+		 * split unquoted substrings, yet not split quoted ones
+		 * (except according to $@ rules); but this leaves the
+		 * unquoted substrings unsplit, and other code below
+		 * for spbreak splits even within the quoted substrings.
+		 *
+		 * TODO: I think multsub needs to be told enough to
+		 * decide about splitting with spbreak at this point
+		 * (and equally in the `=' handler below).  Then
+		 * we can turn off spbreak to avoid the join & split
+		 * nastiness later.
+		 *
+		 * What we really want to do is make this look as
+		 * if it were the result of an assignment from
+		 * the same value, taking account of quoting.
+		 */
+		multsub(&val, (aspar ? NULL : &aval), &isarr, NULL);
+		copied = 1;
+	    }
+	    break;
+	case ':':
+	    /* this must be `::=', unconditional assignment */
+	    if (*s != '=' && *s != Equals)
+		goto noclosebrace;
+	    vunset = 1;
+	    s++;
+	    /* Fall through */
+	case '=':
+	case Equals:
+	    if (vunset) {
+		char sav = *idend;
+		int l;
+		*idend = '\0';
+		val = dupstring(s);
+		isarr = 0;
+		/*
+		 * TODO: this is one of those places where I don't
+		 * think we want to do the joining until later on.
+		 * We also need to handle spbreak and spsep at this
+		 * point and unset them.
+		 */
+		if (spsep || spbreak || !arrasg)
+		    multsub(&val, NULL, NULL, sep);
+		else
+		    multsub(&val, &aval, &isarr, NULL);
+		if (arrasg) {
+		    /*
+		     * This is an array assignment in a context
+		     * where we have no syntactic way of finding
+		     * out what an array element is.  So we just guess.
+		     */
+		    char *arr[2], **t, **a, **p;
+		    if (spsep || spbreak) {
+			aval = sepsplit(val, spsep, 0, 1);
+			isarr = 2;
+			l = arrlen(aval);
+			if (l && !*(aval[l-1]))
+			    l--;
+			if (l && !**aval)
+			    l--, t = aval + 1;
+			else
+			    t = aval;
+		    } else if (!isarr) {
+			if (!*val && arrasg > 1) {
+			    arr[0] = NULL;
+			    l = 0;
+			} else {
+			    arr[0] = val;
+			    arr[1] = NULL;
+			    l = 1;
+			}
+			t = aval = arr;
+		    } else
+			l = arrlen(aval), t = aval;
+		    p = a = zalloc(sizeof(char *) * (l + 1));
+		    while (l--) {
+			untokenize(*t);
+			*p++ = ztrdup(*t++);
+		    }
+		    *p++ = NULL;
+		    if (arrasg > 1) {
+			Param pm = sethparam(idbeg, a);
+			if (pm)
+			    aval = paramvalarr(pm->gsu.h->getfn(pm), hkeys|hvals);
+		    } else
+			setaparam(idbeg, a);
+		} else {
+		    untokenize(val);
+		    setsparam(idbeg, ztrdup(val));
+		}
+		*idend = sav;
+		copied = 1;
+		if (isarr) {
+		  if (nojoin)
+		    isarr = -1;
+		  if (qt && !getlen && isarr > 0 && !spsep && spbreak < 2) {
+		    val = sepjoin(aval, sep, 1);
+		    isarr = 0;
+		  }
+		  sep = spsep = NULL;
+		  spbreak = 0;
+		}
+	    }
+	    break;
+	case '?':
+	case Quest:
+	    if (vunset) {
+		char *msg;
+		*idend = '\0';
+		msg = tricat(idbeg, ": ", *s ? s : "parameter not set");
+		zerr("%s", msg, 0);
+		zsfree(msg);
+		if (!interact)
+		    exit(1);
+		return NULL;
+	    }
+	    break;
+	case '%':
+	case '#':
+	case Pound:
+	case '/':
+/* This once was executed only `if (qt) ...'. But with that
+* patterns in a expansion resulting from a ${(e)...} aren't
+* tokenized even though this function thinks they are (it thinks
+* they are because subst_parse_str() turns Qstring tokens
+* into String tokens and for unquoted parameter expansions the
+* lexer normally does tokenize patterns inside parameter
+* expansions). */
+{
+		int one = noerrs, oef = errflag, haserr;
+		if (!quoteerr)
+		    noerrs = 1;
+		haserr = parse_subst_string(s);
+		noerrs = one;
+		if (!quoteerr) {
+		    errflag = oef;
+		    if (haserr)
+			shtokenize(s);
+		} else if (haserr || errflag) {
+		    zerr("parse error in ${...%c...} substitution",
+			 NULL, s[-1]);
+		    return NULL;
+		}
+	    }
+	    {
+#if 0
+		/*
+		 * This allows # and % to be at the start of
+		 * a parameter in the substitution, which is
+		 * a bit nasty, and can be done (although
+		 * less efficiently) with anchors.
+		 */
+		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++;
+		    }
+		}
+#else
+		singsub(&s);
+#endif
+	    }
+	    /*
+	     * Either loop over an array doing replacements or
+	     * do the replacment on a string.
+	     */
+	    if (!vunset && isarr) {
+		getmatcharr(&aval, s, flags, flnum, replstr);
+		copied = 1;
+	    } else {
+		if (vunset)
+		    val = dupstring("");
+		getmatch(&val, s, flags, flnum, replstr);
+		copied = 1;
+	    }
+	    break;
+	}
+} else {			/* no ${...=...} or anything, but possible modifiers. */
+	/*
+	 * Handler ${+...}.  TODO: strange, why do we handle this only
+	 * if there isn't a trailing modifier?  Why don't we do this
+	 * e.g. when we hanlder the ${(t)...} flag?
+	 */
+	if (chkset) {
+	    val = dupstring(vunset ? "0" : "1");
+	    isarr = 0;
+	} else if (vunset) {
+	    if (unset(UNSET)) {
+		*idend = '\0';
+		zerr("%s: parameter not set", idbeg, 0);
+		return NULL;
+	    }
+	    val = dupstring("");
+	}
+	if (colf) {
+	    /*
+	     * History style colon modifiers.  May need to apply
+	     * on multiple elements of an array.
+	     */
+	    s--;
+	    if (unset(KSHARRAYS) || inbrace) {
+		if (!isarr)
+		    modify(&val, &s);
+		else {
+		    char *ss;
+		    char **ap = aval;
+		    char **pp = aval = (char **) hcalloc(sizeof(char *) *
+							 (arrlen(aval) + 1));
+		    while ((*pp = *ap++)) {
+			ss = s;
+			modify(pp++, &ss);
+		    }
+		    if (pp == aval) {
+			char *t = "";
+			ss = s;
+			modify(&t, &ss);
+		    }
+		    s = ss;
+		}
+		copied = 1;
+		if (inbrace && *s) {
+		    if (*s == ':' && !imeta(s[1]))
+			zerr("unrecognized modifier `%c'", NULL, s[1]);
+		    else
+			zerr("unrecognized modifier", NULL, 0);
+		    return NULL;
+		}
+	    }
+	}
+	if (!inbrace)
+	    fstr = s;
+}
+if (errflag)
+	return NULL;
+/*
+* This handles taking a length with ${#foo} and variations.
+* TODO: again. one might naively have thought this had the
+* same sort of effect as the ${(t)...} flag and the ${+...}
+* test, although in this case we do need the value rather
+* the the parameter, so maybe it's a bit different.
+*/
+if (getlen) {
+	long len = 0;
+	char buf[14];
+	if (isarr) {
+	    char **ctr;
+	    int sl = sep ? ztrlen(sep) : 1;
+	    if (getlen == 1)
+		for (ctr = aval; *ctr; ctr++, len++);
+	    else if (getlen == 2) {
+		if (*aval)
+		    for (len = -sl, ctr = aval;
+			 len += sl + ztrlen(*ctr), *++ctr;);
+	    }
+	    else
+		for (ctr = aval;
+		     *ctr;
+		     len += wordcount(*ctr, spsep, getlen > 3), ctr++);
+	} else {
+	    if (getlen < 3)
+		len = ztrlen(val);
+	    else
+		len = wordcount(val, spsep, getlen > 3);
+	}
+	sprintf(buf, "%ld", len);
+	val = dupstring(buf);
+	isarr = 0;
+}
+/*
+* I think this mult_isarr stuff here is used to pass back
+* the setting of whether we are an array to multsub, and
+* thence to the top-level paramsubst().  The way the
+* setting is passed back is completely obscure, however.
+* It's presumably at this point because we try to remember
+* whether the value was `really' an array before massaging
+* some special cases.
+*
+* TODO: YUK.  This is not the right place to turn arrays into
+* scalars; we should pass back as an array, and let the calling
+* code decide how to deal with it.  This is almost certainly
+* a lot harder than it sounds.  Do we really need to handle
+* one-element arrays as scalars at this point?  Couldn't
+* we just test for it later rather than having a multiple-valued
+* wave-function for isarr?
+*/
+mult_isarr = isarr;
+if (isarr > 0 && !plan9 && (!aval || !aval[0])) {
+	val = dupstring("");
+	isarr = 0;
+} else if (isarr && aval && aval[0] && !aval[1]) {
+	/* treat a one-element array as a scalar for purposes of   *
+	 * concatenation with surrounding text (some${param}thing) *
+	 * and rc_expand_param handling.  Note: mult_isarr (above) *
+	 * propagates the true array type from nested expansions.  */
+	val = aval[0];
+	isarr = 0;
+}
+/* ssub is true when we are called from singsub (via prefork).
+* It means that we must join arrays and should not split words. */
+/*
+* TODO: this is what is screwing up the use of SH_WORD_SPLIT
+* after `:-' etc.  If we fix multsub(), we might get away
+* with simply unsetting the appropriate flags when they
+* get handled.
+*/
+if (ssub || spbreak || spsep || sep) {
+	if (isarr)
+	    val = sepjoin(aval, sep, 1), isarr = 0;
+	if (!ssub && (spbreak || spsep)) {
+	    aval = sepsplit(val, spsep, 0, 1);
+	    if (!aval || !aval[0])
+		val = dupstring("");
+	    else if (!aval[1])
+		val = aval[0];
+	    else
+		isarr = 2;
+	}
+	mult_isarr = isarr;
+}
+/*
+* Perform case modififications.
+*/
+if (casmod) {
+	if (isarr) {
+	    char **ap;
+	    if (!copied)
+		aval = arrdup(aval), copied = 1;
+	    ap = aval;
+	    if (casmod == 1)
+		for (; *ap; ap++)
+		    makeuppercase(ap);
+	    else if (casmod == 2)
+		for (; *ap; ap++)
+		    makelowercase(ap);
+	    else
+		for (; *ap; ap++)
+		    makecapitals(ap);
+	} else {
+	    if (!copied)
+		val = dupstring(val), copied = 1;
+	    if (casmod == 1)
+		makeuppercase(&val);
+	    else if (casmod == 2)
+		makelowercase(&val);
+	    else
+		makecapitals(&val);
+	}
+}
+/*
+* Perform prompt-style modifications.
+*/
+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;
+	}
+	/*
+	 * TODO:  It would be really quite nice to abstract the
+	 * isarr and !issarr code into a function which gets
+	 * passed a pointer to a function with the effect of
+	 * the promptexpand bit.  Then we could use this for
+	 * a lot of stuff and bury val/aval/isarr inside a structure
+	 * which gets passed to it.
+	 */
+	if (isarr) {
+	    char **ap;
+	    if (!copied)
+		aval = arrdup(aval), copied = 1;
+	    ap = aval;
+	    for (; *ap; ap++) {
+		char *tmps;
+		unmetafy(*ap, &len);
+		untokenize(*ap);
+		tmps = unmetafy(promptexpand(metafy(*ap, len, META_NOALLOC),
+					     0, NULL, NULL), &len);
+		*ap = dupstring(tmps);
+		free(tmps);
+	    }
+	} else {
+	    char *tmps;
+	    if (!copied)
+		val = dupstring(val), copied = 1;
+	    unmetafy(val, &len);
+	    untokenize(val);
+	    tmps = unmetafy(promptexpand(metafy(val, len, META_NOALLOC),
+					0, NULL, NULL), &len);
+	    val = dupstring(tmps);
+	    free(tmps);
+	}
+	opts[PROMPTSUBST] = ops;
+	opts[PROMPTBANG] = opb;
+	opts[PROMPTPERCENT] = opp;
+}
+/*
+* One of the possible set of quotes to apply, depending on
+* the repetitions of the (q) flag.
+*/
+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);
+	    }
+	}
+}
+/*
+* Transform special characters in the string to make them
+* printable.
+*/
+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);
+	}
+}
+/*
+* Nothing particularly to do with SH_WORD_SPLIT --- this
+* performs lexical splitting on a string as specified by
+* the (z) flag.
+*/
+if (shsplit) {
+	LinkList list = NULL;
+	if (isarr) {
+	    char **ap;
+	    for (ap = aval; *ap; ap++)
+		list = bufferwords(list, *ap, NULL);
+	    isarr = 0;
+	} else
+	    list = bufferwords(NULL, val, NULL);
+	if (!list || !firstnode(list))
+	    val = dupstring("");
+	else if (!nextnode(firstnode(list)))
+	    val = getdata(firstnode(list));
+	else {
+	    char **ap;
+	    LinkNode node;
+	    aval = ap = (char **) zhalloc((countlinknodes(list) + 1) *
+					  sizeof(char *));
+	    for (node = firstnode(list); node; incnode(node))
+		*ap++ = (char *) getdata(node);
+	    *ap = NULL;
+	    mult_isarr = isarr = 2;
+	}
+	copied = 1;
+}
+/*
+* TODO: hmm.  At this point we have to be on our toes about
+* whether we're putting stuff into a line or not, i.e.
+* we don't want to do this from a recursive call; this is
+* probably part of the point of the mult_isarr monkey business.
+* Rather than passing back flags in a non-trivial way, maybe
+* we could decide on the basis of flags passed down to us.
+*
+* This is the ideal place to do any last-minute conversion from
+* array to strings.  However, given all the transformations we've
+* already done, probably if it's going to be done it will already
+* have been.  (I'd really like to keep everying in aval or
+* equivalent and only locally decide if we need to treat it
+* as a scalar.)
+*/
+if (isarr) {
+	char *x;
+	char *y;
+	int xlen;
+	int i;
+	LinkNode on = n;
+	/* Handle the (u) flag; we need this before the next test */
+	if (unique) {
+	    if(!copied)
+		aval = arrdup(aval);
+	    i = arrlen(aval);
+	    if (i > 1)
+		zhuniqarray(aval);
+	}
+	if ((!aval[0] || !aval[1]) && !plan9) {
+	    /*
+	     * Empty array or single element.  Currently you only
+	     * get a single element array at this point from the
+	     * unique expansion above. but we can potentially
+	     * have other reasons.
+	     *
+	     * The following test removes the markers
+	     * from surrounding double quotes, but I don't know why
+	     * that's necessary.
+	     */
+	    int vallen;
+	    if (aptr > (char *) getdata(n) &&
+		aptr[-1] == Dnull && *fstr == Dnull)
+		*--aptr = '\0', fstr++;
+	    vallen = aval[0] ? strlen(aval[0]) : 0;
+	    y = (char *) hcalloc((aptr - ostr) + vallen + strlen(fstr) + 1);
+	    strcpy(y, ostr);
+	    *str = y + (aptr - ostr);
+	    if (vallen)
+	    {
+		strcpy(*str, aval[0]);
+		*str += vallen;
+	    }
+	    strcpy(*str, fstr);
+	    setdata(n, y);
+	    return n;
+	}
+	/* Handle (o) and (O) and their variants */
+	if (sortit) {
+	    if (!copied)
+		aval = arrdup(aval);
+	    if (indord) {
+		if (sortit & 2) {
+		    char *copy;
+		    char **end = aval + arrlen(aval) - 1, **start = aval;
+		    /* reverse the array */
+		    while (start < end) {
+			copy = *end;
+			*end-- = *start;
+			*start++ = copy;
+		    }
+		}
+	    } else {
+		static CompareFn sortfn[] = {
+		    strpcmp, invstrpcmp, cstrpcmp, invcstrpcmp,
+		    nstrpcmp, invnstrpcmp, instrpcmp, invinstrpcmp
+		};
+		i = arrlen(aval);
+		if (i && (*aval[i-1] || --i))
+		    qsort(aval, i, sizeof(char *), sortfn[sortit-1]);
+	    }
+	}
+	if (plan9) {
+	    /* Handle RC_EXPAND_PARAM */
+	    LinkNode tn;
+	    local_list1(tl);
+	    *--fstr = Marker;
+	    init_list1(tl, fstr);
+	    if (!eval && !stringsubst(&tl, firstnode(&tl), ssub, 0))
+		return NULL;
+	    *str = aptr;
+	    tn = firstnode(&tl);
+	    while ((x = *aval++)) {
+		if (prenum || postnum)
+		    x = dopadding(x, prenum, postnum, preone, postone,
+				  premul, postmul);
+		if (eval && subst_parse_str(&x, (qt && !nojoin), quoteerr))
+		    return NULL;
+		xlen = strlen(x);
+		for (tn = firstnode(&tl);
+		     tn && *(y = (char *) getdata(tn)) == Marker;
+		     incnode(tn)) {
+		    strcatsub(&y, ostr, aptr, x, xlen, y + 1, globsubst,
+			      copied);
+		    if (qt && !*y && isarr != 2)
+			y = dupstring(nulstring);
+		    if (plan9)
+			setdata(n, (void *) y), plan9 = 0;
+		    else
+			insertlinknode(l, n, (void *) y), incnode(n);
+		}
+	    }
+	    for (; tn; incnode(tn)) {
+		y = (char *) getdata(tn);
+		if (*y == Marker)
+		    continue;
+		if (qt && !*y && isarr != 2)
+		    y = dupstring(nulstring);
+		if (plan9)
+		    setdata(n, (void *) y), plan9 = 0;
+		else
+		    insertlinknode(l, n, (void *) y), incnode(n);
+	    }
+	    if (plan9) {
+		uremnode(l, n);
+		return n;
+	    }
+	} else {
+	    /*
+	     * Not RC_EXPAND_PARAM: simply join the first and
+	     * last values.
+	     * TODO: how about removing the restriction that
+	     * aval[1] is non-NULL to promote consistency?, or
+	     * simply changing the test so that we drop into
+	     * the scalar branch, instead of tricking isarr?
+	     */
+	    x = aval[0];
+	    if (prenum || postnum)
+		x = dopadding(x, prenum, postnum, preone, postone,
+			      premul, postmul);
+	    if (eval && subst_parse_str(&x, (qt && !nojoin), quoteerr))
+		return NULL;
+	    xlen = strlen(x);
+	    strcatsub(&y, ostr, aptr, x, xlen, NULL, globsubst, copied);
+	    if (qt && !*y && isarr != 2)
+		y = dupstring(nulstring);
+	    setdata(n, (void *) y);
+	    i = 1;
+	    /* aval[1] is non-null here */
+	    while (aval[i + 1]) {
+		x = aval[i++];
+		if (prenum || postnum)
+		    x = dopadding(x, prenum, postnum, preone, postone,
+				  premul, postmul);
+		if (eval && subst_parse_str(&x, (qt && !nojoin), quoteerr))
+		    return NULL;
+		if (qt && !*x && isarr != 2)
+		    y = dupstring(nulstring);
+		else {
+		    y = dupstring(x);
+		    if (globsubst)
+			shtokenize(y);
+		}
+		insertlinknode(l, n, (void *) y), incnode(n);
+	    }
+	    x = aval[i];
+	    if (prenum || postnum)
+		x = dopadding(x, prenum, postnum, preone, postone,
+			      premul, postmul);
+	    if (eval && subst_parse_str(&x, (qt && !nojoin), quoteerr))
+		return NULL;
+	    xlen = strlen(x);
+	    *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);
+	}
+	if (eval)
+	    n = on;
+} else {
+	/*
+	 * Scalar value.  Handle last minute transformations
+	 * such as left- or right-padding and the (e) flag to
+	 * revaluate the result.
+	 */
+	int xlen;
+	char *x;
+	char *y;
+	x = val;
+	if (prenum || postnum)
+	    x = dopadding(x, prenum, postnum, preone, postone,
+			  premul, postmul);
+	if (eval && subst_parse_str(&x, (qt && !nojoin), quoteerr))
+	    return NULL;
+	xlen = strlen(x);
+	*str = strcatsub(&y, ostr, aptr, x, xlen, fstr, globsubst, copied);
+	if (qt && !*y)
+	    y = dupstring(nulstring);
+	setdata(n, (void *) y);
+}
+if (eval)
+	*str = (char *) getdata(n);
+return n;
+}
+/*
+* Arithmetic substitution: `a' is the string to be evaluated, `bptr'
+* points to the beginning of the string containing it.  The tail of
+* the string is given by `rest'. *bptr is modified with the substituted
+* string. The function returns a pointer to the tail in the substituted
+* string.
+*/
+/**/
+static char *
+arithsubst(char *a, char **bptr, char *rest)
+{
+char *s = *bptr, *t;
+char buf[BDIGBUFSIZE], *b = buf;
+mnumber v;
+singsub(&a);
+v = matheval(a);
+if ((v.type & MN_FLOAT) && !outputradix)
+	b = convfloat(v.u.d, 0, 0, NULL);
+else {
+	if (v.type & MN_FLOAT)
+	    v.u.l = (zlong) v.u.d;
+	convbase(buf, v.u.l, outputradix);
+}
+t = *bptr = (char *) hcalloc(strlen(*bptr) + strlen(b) +
+				 strlen(rest) + 1);
+t--;
+while ((*++t = *s++));
+t--;
+while ((*++t = *b++));
+strcat(t, rest);
+return t;
+}
+/**/
+void
+modify(char **str, char **ptr)
+{
+char *ptr1, *ptr2, *ptr3, del, *lptr, c, *test, *sep, *t, *tt, tc, *e;
+char *copy, *all, *tmp, sav;
+int gbal, wall, rec, al, nl;
+test = NULL;
+if (**ptr == ':')
+	*str = dupstring(*str);
+while (**ptr == ':') {
+	lptr = *ptr;
+	(*ptr)++;
+	wall = gbal = 0;
+	rec = 1;
+	c = '\0';
+	sep = NULL;
+	for (; !c && **ptr;) {
+	    switch (**ptr) {
+	    case 'h':
+	    case 'r':
+	    case 'e':
+	    case 't':
+	    case 'l':
+	    case 'u':
+	    case 'q':
+	    case 'Q':
+		c = **ptr;
+		break;
+	    case 's':
+		c = **ptr;
+		(*ptr)++;
+		ptr1 = *ptr;
+		del = *ptr1++;
+		for (ptr2 = ptr1; *ptr2 != del && *ptr2; ptr2++);
+		if (!*ptr2) {
+		    zerr("bad substitution", NULL, 0);
+		    return;
+		}
+		*ptr2++ = '\0';
+		for (ptr3 = ptr2; *ptr3 != del && *ptr3; ptr3++);
+		if ((sav = *ptr3))
+		    *ptr3++ = '\0';
+		if (*ptr1) {
+		    zsfree(hsubl);
+		    hsubl = ztrdup(ptr1);
+		}
+		if (!hsubl) {
+		    zerr("no previous substitution", NULL, 0);
+		    return;
+		}
+		zsfree(hsubr);
+		for (tt = hsubl; *tt; tt++)
+		    if (INULL(*tt))
+			chuck(tt--);
+		untokenize(hsubl);
+		for (tt = hsubr = ztrdup(ptr2); *tt; tt++)
+		    if (INULL(*tt))
+			chuck(tt--);
+		ptr2[-1] = del;
+		if (sav)
+		    ptr3[-1] = sav;
+		*ptr = ptr3 - 1;
+		break;
+	    case '&':
+		c = 's';
+		break;
+	    case 'g':
+		(*ptr)++;
+		gbal = 1;
+		break;
+	    case 'w':
+		wall = 1;
+		(*ptr)++;
+		break;
+	    case 'W':
+		wall = 1;
+		(*ptr)++;
+		ptr1 = get_strarg(ptr2 = *ptr);
+		if ((sav = *ptr1))
+		    *ptr1 = '\0';
+		sep = dupstring(ptr2 + 1);
+		if (sav)
+		    *ptr1 = sav;
+		*ptr = ptr1 + 1;
+		c = '\0';
+		break;
+	    case 'f':
+		rec = -1;
+		(*ptr)++;
+		break;
+	    case 'F':
+		rec = get_intarg(ptr);
+		(*ptr)++;
+		break;
+	    default:
+		*ptr = lptr;
+		return;
+	    }
+	}
+	(*ptr)++;
+	if (!c) {
+	    *ptr = lptr;
+	    return;
+	}
+	if (rec < 0)
+	    test = dupstring(*str);
+	while (rec--) {
+	    if (wall) {
+		al = 0;
+		all = NULL;
+		for (t = e = *str; (tt = findword(&e, sep));) {
+		    tc = *e;
+		    *e = '\0';
+		    copy = dupstring(tt);
+		    *e = tc;
+		    switch (c) {
+		    case 'h':
+			remtpath(&copy);
+			break;
+		    case 'r':
+			remtext(&copy);
+			break;
+		    case 'e':
+			rembutext(&copy);
+			break;
+		    case 't':
+			remlpaths(&copy);
+			break;
+		    case 'l':
+			downcase(&copy);
+			break;
+		    case 'u':
+			upcase(&copy);
+			break;
+		    case 's':
+			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 *)zhalloc(nl + 1);
+		    if (all)
+			for (ptr2 = all; *ptr2;)
+			    *ptr1++ = *ptr2++;
+		    for (ptr2 = t; *ptr2;)
+			*ptr1++ = *ptr2++;
+		    *tt = tc;
+		    for (ptr2 = copy; *ptr2;)
+			*ptr1++ = *ptr2++;
+		    *ptr1 = '\0';
+		    al = nl;
+		    all = tmp;
+		    t = e;
+		}
+		*str = all;
+	    } else {
+		switch (c) {
+		case 'h':
+		    remtpath(str);
+		    break;
+		case 'r':
+		    remtext(str);
+		    break;
+		case 'e':
+		    rembutext(str);
+		    break;
+		case 't':
+		    remlpaths(str);
+		    break;
+		case 'l':
+		    downcase(str);
+		    break;
+		case 'u':
+		    upcase(str);
+		    break;
+		case 's':
+		    if (hsubl && hsubr) {
+			char *oldstr = *str;
+			subst(str, hsubl, hsubr, gbal);
+			if (*str != oldstr) {
+			    *str = dupstring(oldstr = *str);
+			    zsfree(oldstr);
+			}
+		    }
+		    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) {
+		if (!strcmp(test, *str))
+		    rec = 0;
+		else
+		    test = dupstring(*str);
+	    }
+	}
+}
+}
+/* get a directory stack entry */
+/**/
+static char *
+dstackent(char ch, int val)
+{
+int backwards;
+LinkNode end=(LinkNode)dirstack, n;
+backwards = ch == (isset(PUSHDMINUS) ? '+' : '-');
+if(!backwards && !val--)
+	return pwd;
+if (backwards)
+	for (n=lastnode(dirstack); n != end && val; val--, n=prevnode(n));
+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;
+}
+return (char *)getdata(n);
+}

changeset 0	2e3d3ce01487
child 4	0fdb7f6b0309