27304: add ${(q-)..} flag

6 files changed, 181 insertions, 28 deletions

diff --git a/ChangeLog b/ChangeLog
index f25811e1b..6aed3f6c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-06-05  Peter Stephenson  <pws@csr.com>
+
+	* 27304: Doc/Zsh/expn.yo, Src/subst.c, Src/utils.c, Src/zsh.h,
+	Test/D04parameter.ztst:  add ${(q-)...} flag to do minimal
+	quoting of arguments with no unnecessary single quotes.
+
 2009-06-04  Peter Stephenson  <pws@csr.com>
 
 	* Baptiste Daroussin: 27033: Completion/BSD/Command/_portaudit,
@@ -11828,5 +11834,5 @@
 
 *****************************************************
 * This is used by the shell to define $ZSH_PATCHLEVEL
-* $Revision: 1.4712 $
+* $Revision: 1.4713 $
 *****************************************************
diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo
index bab12cc3f..59b6aeb87 100644
--- a/Doc/Zsh/expn.yo
+++ b/Doc/Zsh/expn.yo
@@ -825,14 +825,22 @@ have `tt(foo=bar)' and `tt(bar=baz)', the strings tt(${(P)foo}),
 tt(${(P)${foo}}), and tt(${(P)$(echo bar)}) will be expanded to `tt(baz)'.
 )
 item(tt(q))(
-Quote the resulting words with backslashes; unprintable or invalid
-characters are quoted using the tt($'\)var(NNN)tt(') form, with separate
-quotes for each octet.  If this flag is given
-twice, the resulting words are quoted in single quotes and if it is
-given three times, the words are quoted in double quotes; in these forms
-no special handling of unprintable or invalid characters is attempted.  If
-the flag is given four times, the words are quoted in single quotes
-preceded by a tt($).
+Quote characters that are special to the shell in the resulting words with
+backslashes; unprintable or invalid characters are quoted using the
+tt($'\)var(NNN)tt(') form, with separate quotes for each octet.
+
+If this flag is given twice, the resulting words are quoted in single
+quotes and if it is given three times, the words are quoted in double
+quotes; in these forms no special handling of unprintable or invalid
+characters is attempted.  If the flag is given four times, the words are
+quoted in single quotes preceded by a tt($).  Note that in all three of
+these forms quoting is done unconditionally, even if this does not change
+the way the resulting string would be interpreted by the shell.
+
+If a tt(q-) is given (only a single tt(q) may appear), a minimal
+form of single quoting is used that only quotes the string if needed to
+protect special characters.  Typically this form gives the most readable
+output.
 )
 item(tt(Q))(
 Remove one level of quotes from the resulting words.
diff --git a/Src/subst.c b/Src/subst.c
index 5d14c458a..0bb0b798f 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -1583,6 +1583,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		switch (c) {
 		case ')':
 		case Outpar:
+		    /* how can this happen? */
 		    break;
 		case '~':
 		case Tilde:
@@ -1653,7 +1654,17 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    break;
 
 		case 'q':
-		    quotemod++, quotetype++;
+		    if (quotetype == QT_DOLLARS)
+			goto flagerr;
+		    if (s[1] == '-') {
+			if (quotemod)
+			    goto flagerr;
+			s++;
+			quotemod = 1;
+			quotetype = QT_SINGLE_OPTIONAL;
+		    } else {
+			quotemod++, quotetype++;
+		    }
 		    break;
 		case 'Q':
 		    quotemod--;
@@ -2801,8 +2812,26 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
      * the repetitions of the (q) flag.
      */
     if (quotemod) {
-	if (quotetype > QT_DOLLARS)
-	    quotetype = QT_DOLLARS;
+	int pre = 0, post = 0;
+
+	if (quotemod > 0 && quotetype > QT_BACKSLASH) {
+	    switch (quotetype)
+	    {
+	    case QT_DOLLARS:
+		/* space for "$" */
+		pre = 2;
+		post = 1;
+		break;
+
+	    case QT_SINGLE_OPTIONAL:
+		/* quotes will be added for us */
+		break;
+
+	    default:
+		pre = post = 1;
+		break;
+	    }
+	}
 	if (isarr) {
 	    char **ap;
 
@@ -2816,13 +2845,13 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		    char *tmp;
 
 		    for (; *ap; ap++) {
-			int pre = quotetype != QT_DOLLARS ? 1 : 2;
 			tmp = quotestring(*ap, NULL, quotetype);
 			sl = strlen(tmp);
-			*ap = (char *) zhalloc(pre + sl + 2);
+			*ap = (char *) zhalloc(pre + sl + post + 1);
 			strcpy((*ap) + pre, tmp);
-			ap[0][pre - 1] = ap[0][pre + sl] =
-			    (quotetype != QT_DOUBLE ? '\'' : '"');
+			if (pre)
+			    ap[0][pre - 1] = ap[0][pre + sl] =
+				(quotetype != QT_DOUBLE ? '\'' : '"');
 			ap[0][pre + sl + 1] = '\0';
 			if (quotetype == QT_DOLLARS)
 			  ap[0][0] = '$';
@@ -2853,15 +2882,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub)
 		val = dupstring(val), copied = 1;
 	    if (quotemod > 0) {
 		if (quotetype > QT_BACKSLASH) {
-		    int pre = quotetype != QT_DOLLARS ? 1 : 2;
 		    int sl;
 		    char *tmp;
 		    tmp = quotestring(val, NULL, quotetype);
 		    sl = strlen(tmp);
 		    val = (char *) zhalloc(pre + sl + 2);
 		    strcpy(val + pre, tmp);
-		    val[pre - 1] = val[pre + sl] =
-			(quotetype != QT_DOUBLE ? '\'' : '"');
+		    if (pre)
+			val[pre - 1] = val[pre + sl] =
+			    (quotetype != QT_DOUBLE ? '\'' : '"');
 		    val[pre + sl + 1] = '\0';
 		    if (quotetype == QT_DOLLARS)
 		      val[0] = '$';
diff --git a/Src/utils.c b/Src/utils.c
index 00d51a320..687a396fa 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -4408,6 +4408,11 @@ addunprintable(char *v, const char *u, const char *uend)
  * 
  * The last argument is a QT_ value defined in zsh.h other than QT_NONE.
  *
+ * Most quote styles other than backslash assume the quotes are to
+ * be added outside quotestring().  QT_SINGLE_OPTIONAL is different:
+ * the single quotes are only added where necessary, so the
+ * whole expression is handled here.
+ *
  * The string may be metafied and contain tokens.
  */
 
@@ -4417,20 +4422,50 @@ quotestring(const char *s, char **e, int instring)
 {
     const char *u, *tt;
     char *v;
+    int alloclen;
+    char *buf;
+    int sf = 0;
     /*
-     * With QT_BACKSLASH we may need to use $'\300' stuff.
-     * Keep memory usage within limits by allocating temporary
-     * storage and using heap for correct size at end.
+     * quotesub is used with QT_SINGLE_OPTIONAL.
+     * quotesub = 0:  mechanism not active
+     * quotesub = 1:  mechanism pending, no "'" yet;
+     *                needs adding at quotestart.
+     * quotesub = 2:  mechanism active, added opening "'"; need
+     *                closing "'".
      */
-    int alloclen = (instring == QT_BACKSLASH ? 7 : 4) * strlen(s) + 1;
-    char *buf = zshcalloc(alloclen);
-    int sf = 0;
+    int quotesub = 0;
+    char *quotestart;
     convchar_t cc;
     const char *uend;
 
-    DPUTS(instring < QT_BACKSLASH || instring > QT_DOLLARS,
+    switch (instring)
+    {
+    case QT_BACKSLASH:
+	/*
+	 * With QT_BACKSLASH we may need to use $'\300' stuff.
+	 * Keep memory usage within limits by allocating temporary
+	 * storage and using heap for correct size at end.
+	 */
+	alloclen = strlen(s) * 7 + 1;
+	break;
+
+    case QT_SINGLE_OPTIONAL:
+	/*
+	 * Here, we may need to add single quotes.
+	 */
+	alloclen = strlen(s) * 4 + 3;
+	quotesub = 1;
+	break;
+
+    default:
+	alloclen = strlen(s) * 4 + 1;
+	break;
+    }
+    tt = quotestart = v = buf = zshcalloc(alloclen);
+
+    DPUTS(instring < QT_BACKSLASH || instring == QT_BACKTICK ||
+	  instring > QT_SINGLE_OPTIONAL,
 	  "BUG: bad quote type in quotestring");
-    tt = v = buf;
     u = s;
     if (instring == QT_DOLLARS) {
 	/*
@@ -4526,12 +4561,64 @@ quotestring(const char *s, char **e, int instring)
 		       (u[-1] == '=' || u[-1] == ':')) ||
 		      (*u == '~' && isset(EXTENDEDGLOB))) &&
 		     (instring == QT_BACKSLASH ||
+		      instring == QT_SINGLE_OPTIONAL ||
 		      (isset(BANGHIST) && *u == (char)bangchar &&
 		       instring != QT_SINGLE) ||
 		      (instring == QT_DOUBLE &&
 		       (*u == '$' || *u == '`' || *u == '\"' || *u == '\\')) ||
 		      (instring == QT_SINGLE && *u == '\''))) {
-		if (*u == '\n' || (instring == QT_SINGLE && *u == '\'')) {
+		if (instring == QT_SINGLE_OPTIONAL) {
+		    if (quotesub == 1) {
+			/*
+			 * We haven't yet had to quote at the start.
+			 */
+			if (*u == '\'') {
+			    /*
+			     * We don't need to.
+			     */
+			    *v++ = '\\';
+			} else {
+			    /*
+			     * It's now time to add quotes.
+			     */
+			    if (v > quotestart)
+			    {
+				char *addq;
+
+				for (addq = v; addq > quotestart; addq--)
+				    *addq = addq[-1];
+			    }
+			    *quotestart = '\'';
+			    v++;
+			    quotesub = 2;
+			}
+			*v++ = *u++;
+			/*
+			 * Next place to start quotes is here.
+			 */
+			quotestart = v;
+		    } else if (*u == '\'') {
+			if (unset(RCQUOTES)) {
+			    *v++ = '\'';
+			    *v++ = '\\';
+			    *v++ = '\'';
+			    /* Don't restart quotes unless we need them */
+			    quotesub = 1;
+			    quotestart = v;
+			} else {
+			    /* simplest just to use '' always */
+			    *v++ = '\'';
+			    *v++ = '\'';
+			}
+			/* dealt with */
+			u++;
+		    } else {
+			/* else already quoting, just add */
+			*v++ = *u++;
+		    }
+		    continue;
+		} else if (*u == '\n' ||
+			   (instring == QT_SINGLE && *u == '\'')) {
 		    if (unset(RCQUOTES)) {
 			*v++ = '\'';
 			if (*u == '\'')
@@ -4589,6 +4676,8 @@ quotestring(const char *s, char **e, int instring)
 	    }
 	}
     }
+    if (quotesub == 2)
+	*v++ = '\'';
     *v = '\0';
 
     if (e && *e == u)
diff --git a/Src/zsh.h b/Src/zsh.h
index 3c1623c1f..3854116c0 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -210,8 +210,15 @@ enum {
      * in those cases where we need to represent a complete set.
      */
     QT_BACKTICK,
+    /*
+     * Single quotes, but the default is not to quote unless necessary.
+     * This is only useful as an argument to quotestring().
+     */
+    QT_SINGLE_OPTIONAL
 };
 
+#define QT_IS_SINGLE(x)	((x) == QT_SINGLE || (x) == QT_SINGLE_OPTIONAL)
+
 /*
  * Lexical tokens: unlike the character tokens above, these never
  * appear in strings and don't necessarily represent a single character.
diff --git a/Test/D04parameter.ztst b/Test/D04parameter.ztst
index 4cd137bbd..358b46ef7 100644
--- a/Test/D04parameter.ztst
+++ b/Test/D04parameter.ztst
@@ -319,11 +319,25 @@
   print -r ${(qq)foo}
   print -r ${(qqq)foo}
   print -r ${(qqqq)foo}
+  print -r ${(q-)foo}
 0:${(q...)...}
 >playing\ \'stupid\'\ \"games\"\ \\w\\i\\t\\h\ \$quoting.
 >'playing '\''stupid'\'' "games" \w\i\t\h $quoting.'
 >"playing 'stupid' \"games\" \\w\\i\\t\\h \$quoting."
 >$'playing \'stupid\' "games" \\w\\i\\t\\h $quoting.'
+>'playing '\'stupid\'' "games" \w\i\t\h $quoting.'
+
+  print -r -- ${(q-):-foo}
+  print -r -- ${(q-):-foo bar}
+  print -r -- ${(q-):-"*(.)"}
+  print -r -- ${(q-):-"wow 'this is cool' or is it?"}
+  print -r -- ${(q-):-"no-it's-not"}
+0:${(q-)...} minimal single quoting
+>foo
+>'foo bar'
+>'*(.)'
+>'wow '\''this is cool'\'' or is it?'
+>no-it\'s-not
 
   foo="'and now' \"even the pubs\" \\a\\r\\e shut."
   print -r ${(Q)foo}