Re: quote modifier for parameter expansion?

Re: quote modifier for parameter expansion?

[Sven Wischnowsky]

I wrote:

> But it's also useful if you stuff a string together in a parameter and 
> later use the value of that parameter for globbing. With `:q' you can
> prevent pattern characters in the original parameters from being
> interpreted as a pattern.
> 
> That's what makes it useful in functions like pfiles(). Without the
> patch below and using:
> 
>   zle -C my-comp complete-word main-complete
> 
> doing `foo *<TAB>' will give one all files as possible completions.

Yesterday evening I realised that the patch for the `:q' modifier
wasn't that useful in the form I sent it. The problem is that you
might want to use ${foo#...} or somthing like this on the result but
then the single quotes may become unbalanced and nasty things like
that (in fact, the completion examples do this and hence the patch for
the new-completion-examples-file breaks it).

So we should either make :q use backslashes to quote the string or not 
add it at all. The patch below uses the quotename() function from the
completion code for this, moving it to utils.c and renaming it.
Of course, this also makes it differ from the history modifier :q.

As for (t)csh, the effect of $foo:q is to keep the result from being
processed any further (namely globbing) which normally happens in
those shells (so this is one quoting level further down).

All this makes :q look less friendly for me (but it still may be
useful).

Bye
 Sven

diff -u os/subst.c Src/subst.c
--- os/subst.c	Thu Feb  4 21:43:14 1999
+++ Src/subst.c	Thu Feb  4 21:35:54 1999
@@ -1828,7 +1828,7 @@
 			    subst(&copy, hsubl, hsubr, gbal);
 			break;
 		    case 'q':
-			quote(&copy);
+			copy = bslashquote(copy, NULL, NULL, NULL, 0);
 			break;
 		    }
 		    tc = *tt;
@@ -1882,7 +1882,7 @@
 		    }
 		    break;
 		case 'q':
-		    quote(str);
+		    *str = bslashquote(*str, NULL, NULL, NULL, 0);
 		    break;
 		}
 	    }
diff -u os/utils.c Src/utils.c
--- os/utils.c	Thu Feb  4 21:43:14 1999
+++ Src/utils.c	Thu Feb  4 21:39:05 1999
@@ -3109,6 +3109,73 @@
     return 0;
 }
 
+/* Quote the string s and return the result.  If e is non-zero, the         *
+ * pointer it points to may point to a position in s and in e the position  *
+ * of the corresponding character in the quoted string is returned.  Like   *
+ * e, te may point to a position in the string and pl is used to return     *
+ * the position of the character pointed to by te in the quoted string.     *
+ * The last argument should be zero if this is to be used outside a string, *
+ * one if it is to be quoted for the inside of a single quoted string, and  *
+ * two if it is for the inside of  double quoted string.                    *
+ * The string may be metafied and contain tokens.                           */
+
+/**/
+char *
+bslashquote(const char *s, char **e, char *te, int *pl, int instring)
+{
+    const char *u, *tt;
+    char *v, buf[PATH_MAX * 2];
+    int sf = 0;
+
+    tt = v = buf;
+    u = s;
+    for (; *u; u++) {
+	if (e && *e == u)
+	    *e = v, sf |= 1;
+	if (te == u)
+	    *pl = v - tt, sf |= 2;
+	if (ispecial(*u) &&
+	    (!instring || (isset(BANGHIST) &&
+			   *u == (char)bangchar) ||
+	     (instring == 2 &&
+	      (*u == '$' || *u == '`' || *u == '\"')) ||
+	     (instring == 1 && *u == '\''))) {
+	    if (*u == '\n' || (instring == 1 && *u == '\'')) {
+		if (unset(RCQUOTES)) {
+		    *v++ = '\'';
+		    if (*u == '\'')
+			*v++ = '\\';
+		    *v++ = *u;
+		    *v++ = '\'';
+		} else if (*u == '\n')
+		    *v++ = '"', *v++ = '\n', *v++ = '"';
+		else
+		    *v++ = '\'', *v++ = '\'';
+		continue;
+	    } else
+		*v++ = '\\';
+	}
+	if(*u == Meta)
+	    *v++ = *u++;
+	*v++ = *u;
+    }
+    *v = '\0';
+    if (strcmp(buf, s))
+	tt = dupstring(buf);
+    else
+	tt = s;
+    v += tt - buf;
+    if (e && (sf & 1))
+	*e += tt - buf;
+
+    if (e && *e == u)
+	*e = v;
+    if (te == u)
+	*pl = v - tt;
+
+    return (char *) tt;
+}
+
 /* Unmetafy and output a string, quoted if it contains special characters. */
 
 /**/
diff -u os/Zle/comp1.c Src/Zle/comp1.c
--- os/Zle/comp1.c	Thu Feb  4 19:56:49 1999
+++ Src/Zle/comp1.c	Thu Feb  4 21:45:24 1999
@@ -104,14 +105,8 @@
      *compsuffix,
      *compiprefix;
 
-/* This variable and the functions rembslash() and quotename() came from     *
- * zle_tricky.c, but are now used in compctl.c, too.                         */
-
-/* 1 if we are completing in a string */
-
-/**/
-int instring;
-
+/* The function rembslash() came from zle_tricky.c, but is now used *
+ * in compctl.c, too.                                               */
 
 /**/
 static void
@@ -393,70 +388,6 @@
 	    s++;
 
     return t;
-}
-
-/* Quote the string s and return the result.  If e is non-zero, the        *
- * pointer it points to may point to a position in s and in e the position *
- * of the corresponding character in the quoted string is returned.  Like  *
- * e, te may point to a position in the string and pl is used to return    *
- * the position of the character pointed to by te in the quoted string.    *
- * The string is metafied and may contain tokens.                          */
-
-/**/
-char *
-quotename(const char *s, char **e, char *te, int *pl)
-{
-    const char *u, *tt;
-    char *v, buf[PATH_MAX * 2];
-    int sf = 0;
-
-    tt = v = buf;
-    u = s;
-    for (; *u; u++) {
-	if (e && *e == u)
-	    *e = v, sf |= 1;
-	if (te == u)
-	    *pl = v - tt, sf |= 2;
-	if (ispecial(*u) &&
-	    (!instring || (isset(BANGHIST) &&
-			   *u == (char)bangchar) ||
-	     (instring == 2 &&
-	      (*u == '$' || *u == '`' || *u == '\"')) ||
-	     (instring == 1 && *u == '\''))) {
-	    if (*u == '\n' || (instring == 1 && *u == '\'')) {
-		if (unset(RCQUOTES)) {
-		    *v++ = '\'';
-		    if (*u == '\'')
-			*v++ = '\\';
-		    *v++ = *u;
-		    *v++ = '\'';
-		} else if (*u == '\n')
-		    *v++ = '"', *v++ = '\n', *v++ = '"';
-		else
-		    *v++ = '\'', *v++ = '\'';
-		continue;
-	    } else
-		*v++ = '\\';
-	}
-	if(*u == Meta)
-	    *v++ = *u++;
-	*v++ = *u;
-    }
-    *v = '\0';
-    if (strcmp(buf, s))
-	tt = dupstring(buf);
-    else
-	tt = s;
-    v += tt - buf;
-    if (e && (sf & 1))
-	*e += tt - buf;
-
-    if (e && *e == u)
-	*e = v;
-    if (te == u)
-	*pl = v - tt;
-
-    return (char *) tt;
 }
 
 /**/
diff -u os/Zle/compctl.c Src/Zle/compctl.c
--- os/Zle/compctl.c	Thu Feb  4 19:56:49 1999
+++ Src/Zle/compctl.c	Thu Feb  4 21:41:18 1999
@@ -1385,7 +1385,7 @@
 	    untokenize(p);
 	    quotedzputs(p, stdout);
 	} else
-	    quotedzputs(quotename(s, NULL, NULL, NULL), stdout);
+	    quotedzputs(bslashquote(s, NULL, NULL, NULL, 0), stdout);
     }
 
     /* loop through flags w/o args that are set, printing them if so */
@@ -1515,7 +1515,7 @@
 		char *p = dupstring(s);
 
 		untokenize(p);
-		quotedzputs(quotename(p, NULL, NULL, NULL), stdout);
+		quotedzputs(bslashquote(p, NULL, NULL, NULL, 0), stdout);
 	    }
 	}
 	putchar('\n');
@@ -1547,8 +1547,6 @@
     cclist = 0;
     showmask = 0;
 
-    instring = 0;
-
     /* Parse all the arguments */
     if (*argv) {
 	/* Let's see if this is a global matcher definition. */
diff -u os/Zle/zle_tricky.c Src/Zle/zle_tricky.c
--- os/Zle/zle_tricky.c	Thu Feb  4 20:08:12 1999
+++ Src/Zle/zle_tricky.c	Thu Feb  4 21:40:47 1999
@@ -487,6 +487,16 @@
 
 static int insubscr;
 
+/* 1 if we are completing in a string */
+
+/**/
+int instring;
+
+/* Convenience macro for calling bslashquote() (formerly quotename()). *
+ * This uses the instring variable above.                              */
+
+#define quotename(s, e, te, pl) bslashquote(s, e, te, pl, instring)
+
 /* Check if the given string is the name of a parameter and if this *
  * parameter is one worth expanding.                                */
 

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de

Re: quote modifier for parameter expansion?

[Bart Schaefer]

On Feb 3,  5:02pm, Peter Stephenson wrote:
} Subject: Re: quote modifier for parameter expansion?
}
} Sven Wischnowsky wrote:
} > Hm. I'm sure I'm missing something again, but could anyone please tell 
} > me what? The patch below (which probably shouldn't be used) just uses
} > the quote()-function from hist.c to make the `q' modifier in parameter 
} > expansion work.
} 
} % bar="hello'there"
} % print -r $bar:q
} 'hello'\''there'
} 
} Maybe the point is simply it's got limited application, since unless
} it's going into an eval the extra quotes aren't all that useful,

Maybe the point is that :q is a csh-ism, and that result is nothing like
what csh would produce.

In the old days before people worried about 8-bit characters, :q in csh
simply set the high-order bit of every character in the variable value.
Then those high bits would get stripped off again after all the other
substitutions were applied.  Thus there was no user-visible change to
the string.

That doesn't make it useless, but if we keep it, it belongs in the
section on differences from (t)csh.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Re: quote modifier for parameter expansion?

[Sven Wischnowsky]

Peter Stephenson wrote:

> Sven Wischnowsky wrote:
> > Hm. I'm sure I'm missing something again, but could anyone please tell 
> > me what? The patch below (which probably shouldn't be used) just uses
> > the quote()-function from hist.c to make the `q' modifier in parameter 
> > expansion work. The result is almost always a funny looking string in
> > single quotes, but that alone can't be the reason not to use this
> > function.
> 
> Does exactly what I would expect it to.
> 
> % bar="hello'there"
> % print -r $bar:q
> 'hello'\''there'
> 
> Maybe the point is simply it's got limited application, since unless
> it's going into an eval the extra quotes aren't all that useful,
> unlike in history substitution which happens before the quotes get
> swallowed.

But it's also useful if you stuff a string together in a parameter and 
later use the value of that parameter for globbing. With `:q' you can
prevent pattern characters in the original parameters from being
interpreted as a pattern.

That's what makes it useful in functions like pfiles(). Without the
patch below and using:

  zle -C my-comp complete-word main-complete

doing `foo *<TAB>' will give one all files as possible completions.

Of course, this is the same use as with eval (i.e. double evaluation).

Bye
 Sven

--- om/new-completion-examples	Wed Feb  3 16:16:57 1999
+++ Misc/new-completion-examples	Wed Feb  3 17:25:29 1999
@@ -211,7 +211,7 @@
     ppres=( '' )
   fi
 
-  str="$PREFIX*$SUFFIX"
+  str="${PREFIX:q}*${SUFFIX:q}"
 
   if [[ -z "$a[1]" || "$str[1]" = [~/] || "$str" = (.|..)/* ]] then
     a=()

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de

Re: quote modifier for parameter expansion?

[Peter Stephenson]

Sven Wischnowsky wrote:
> Hm. I'm sure I'm missing something again, but could anyone please tell 
> me what? The patch below (which probably shouldn't be used) just uses
> the quote()-function from hist.c to make the `q' modifier in parameter 
> expansion work. The result is almost always a funny looking string in
> single quotes, but that alone can't be the reason not to use this
> function.

Does exactly what I would expect it to.

% bar="hello'there"
% print -r $bar:q
'hello'\''there'

Maybe the point is simply it's got limited application, since unless
it's going into an eval the extra quotes aren't all that useful,
unlike in history substitution which happens before the quotes get
swallowed.

-- 
Peter Stephenson <pws@ibmth.df.unipi.it>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy

quote modifier for parameter expansion?

[Sven Wischnowsky]

I wrote:

> People using the new style completion stuff (and the new-completion-examples
> find) who test the thing quoted above will notice that it completes
> files beginning with `I' in this case. This is due to the parameter
> handling in pfiles(). More precisely, this is due to the fact that we
> still haven't got a way to quote strings resulting from a parameter
> expansion (supporting the `q' modifier for parameter expansion has
> long been on the wish list but still isn't implemented).

Hm. I'm sure I'm missing something again, but could anyone please tell 
me what? The patch below (which probably shouldn't be used) just uses
the quote()-function from hist.c to make the `q' modifier in parameter 
expansion work. The result is almost always a funny looking string in
single quotes, but that alone can't be the reason not to use this
function.


Bye
 Sven

--- os/subst.c	Wed Feb  3 12:07:13 1999
+++ Src/subst.c	Wed Feb  3 16:36:39 1999
@@ -1708,6 +1708,7 @@
 	    case 't':
 	    case 'l':
 	    case 'u':
+	    case 'q':
 		c = **ptr;
 		break;
 
@@ -1826,6 +1827,9 @@
 			if (hsubl && hsubr)
 			    subst(&copy, hsubl, hsubr, gbal);
 			break;
+		    case 'q':
+			quote(&copy);
+			break;
 		    }
 		    tc = *tt;
 		    *tt = '\0';
@@ -1876,6 +1880,9 @@
 			    zsfree(oldstr);
 			}
 		    }
+		    break;
+		case 'q':
+		    quote(str);
 		    break;
 		}
 	    }

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de