Recursive globbing

Recursive globbing

[Vincent Lefevre]

Hi,

Is there any difference between *.tex and **.tex ? If there's none,
how about having improved recursive globbing, where ** not followed
by a slash would mean **/* (ditto for *** -> ***/*)?

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
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Re: Recursive globbing

[Peter Stephenson]

Vincent Lefevre wrote:
> Hi,
> 
> Is there any difference between *.tex and **.tex ?

No, and in fact they are documented to be the same.  Hence...

> If there's none,
> how about having improved recursive globbing, where ** not followed
> by a slash would mean **/* (ditto for *** -> ***/*)?

I can't see any problem with this, unless people are habitually using
double stars in the place of single stars, for example to avoid having
to prune patterns.  I doubt it, but are they?

Index: Src/glob.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/glob.c,v
retrieving revision 1.33
diff -u -r1.33 glob.c
--- Src/glob.c	6 Apr 2004 17:45:47 -0000	1.33
+++ Src/glob.c	14 May 2004 10:50:20 -0000
@@ -639,14 +639,21 @@
     char *str;
     int compflags = gf_noglobdots ? (PAT_FILE|PAT_NOGLD) : PAT_FILE;
 
-    if (instr[0] == Star && instr[1] == Star &&
-        (instr[2] == '/' || (instr[2] == Star && instr[3] == '/'))) {
+    if (instr[0] == Star && instr[1] == Star) {
 	/* Match any number of directories. */
 	int follow;
 
 	/* with three stars, follow symbolic links */
 	follow = (instr[2] == Star);
-	instr += (3 + follow);
+        if (instr[2] == '/' || (instr[2] == Star && instr[3] == '/')) {
+	    instr += (3 + follow);
+	} else {
+	    /*
+	     * Make **(|[^/\*]*) or ***(|[^/]) equivalent to
+	     * **[/]*(...) or ***[/]*(...), respectively.
+	     */
+	    instr += 1 + follow;
+	}
 
 	/* Now get the next path component if there is one. */
 	l1 = (Complist) zhalloc(sizeof *l1);
Index: Doc/Zsh/expn.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/expn.yo,v
retrieving revision 1.49
diff -u -r1.49 expn.yo
--- Doc/Zsh/expn.yo	6 Apr 2004 09:26:50 -0000	1.49
+++ Doc/Zsh/expn.yo	14 May 2004 10:50:21 -0000
@@ -1590,9 +1590,12 @@
 does a recursive directory search for files named `tt(bar)' (potentially
 including the file `tt(bar)' in the current directory).  This form does not
 follow symbolic links; the alternative form `tt(***/)' does, but is
-otherwise identical.  Neither of these can be combined with other forms of
-globbing within the same path segment; in that case, the `tt(*)'
-operators revert to their usual effect.
+otherwise identical.
+
+As a further shorthand, `tt(**)' or `tt(***)' followed by anything other
+than a `tt(/)' are treated the same way as `tt(**/*)' and `tt(***/*)',
+respectively.  Hence `tt(**.c)' is equivalent to `tt(**/*.c)' and so to
+`tt((*/)#*.c)'.
 subsect(Glob Qualifiers)
 cindex(globbing, qualifiers)
 cindex(qualifiers, globbing)

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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Re: Recursive globbing

[Bart Schaefer]

On Fri, 14 May 2004, Peter Stephenson wrote:

> > Is there any difference between *.tex and **.tex ?
> 
> No, and in fact they are documented to be the same.  Hence...
>
> > how about having improved recursive globbing, where ** not followed
> > by a slash would mean **/* (ditto for *** -> ***/*)?
> 
> I can't see any problem with this

No; please please don't do this.  Consider:

	foo='x*'

	print ${~foo}*

Or

	bar="$foo*"
	print $~bar

Completely unexpected results.

Also it seriously breaks sh compatibility, so at the very least it should
be disabled when SH_GLOB or similar options are in effect.

There's a reason that only **/ and not blather**/ is special.

Re: Recursive globbing

[Peter Stephenson]

Bart Schaefer wrote:
> There's a reason that only **/ and not blather**/ is special.

% print -l tmp**/*.c
tmp/gtk_hello_world.c
tmp/gtk_hello_world2.c
tmp/hal_set_txbb_trim.c
tmp/ptemtst.c
tmp/rx_dynamic_lvl.c

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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Re: Recursive globbing

[Peter Stephenson]

Peter Stephenson wrote:
> Bart Schaefer wrote:
> > There's a reason that only **/ and not blather**/ is special.
> 
> % print -l tmp**/*.c
> tmp/gtk_hello_world.c
> tmp/gtk_hello_world2.c
> tmp/hal_set_txbb_trim.c
> tmp/ptemtst.c
> tmp/rx_dynamic_lvl.c

Ah, wait, I see... it's not printing tmp/subdir/*.c.   That's the effect
you meant.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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parameter type differences?

[S. Cowles]

I have the following script, with appended output.  There are 3 cases tested, 
comparing a reference value for parameter "bref" with 3 values of parameter 
"b".  The utility od is used to verify the values of the "bref" and "b" 
parameters.  

My question is:  why are the values of "b" not equal to "bref" in cases 1 and 
2?  If the issue is parameter type, is there any way to display the parameter 
type for "b"?

Thank you.

================the script=============
#!/bin/zsh
emulate -R zsh
bref='
'
echo "case 1."
b='\012'
[[ ${bref} == ${b} ]] && echo same || echo diff
echo -n "${bref}" | od -b ; echo -n "${b}" | od -b
echo "case 2."
b='\n'
[[ ${bref} == ${b} ]] && echo same || echo diff
echo -n "${bref}" | od -b ; echo -n "${b}" | od -b
echo "case 3."
b='
'
[[ ${bref} == ${b} ]] && echo same || echo diff
echo -n "${bref}" | od -b ; echo -n "${b}" | od -b
exit 0
================the output============
case 1.
diff
0000000 012
0000001
0000000 012
0000001
case 2.
diff
0000000 012
0000001
0000000 012
0000001
case 3.
same
0000000 012
0000001
0000000 012
0000001
==================================

Re: parameter type differences?

[Wayne Davison]

On Sun, May 16, 2004 at 02:34:06PM -0700, S. Cowles wrote:
> The utility od is used to verify the values of the "bref" and "b"
> parameters.  

Except that you used echo to output the value of the variables, and it
interprets escape sequences by default.  If you change all the "echo -n"
calls to "echo -nE", it will show you how the values differ.  Here's the
output of such a modified script:

case 1.
diff
0000000 012
0000001
0000000 134 060 061 062
0000004
case 2.
diff
0000000 012
0000001
0000000 134 156
0000002
case 3.
same
0000000 012
0000001
0000000 012
0000001

To get rid of this discrepancy, put a $ in front of the string literals
you assign to $b, like this:

b=$'\012'

That will put a single character into $b instead of 4.

..wayne..

Re: Recursive globbing

[Vincent Lefevre]

On 2004-05-14 09:10:13 -0700, Bart Schaefer wrote:
> No; please please don't do this.  Consider:
> 
> 	foo='x*'
> 
> 	print ${~foo}*
> 
> Or
> 
> 	bar="$foo*"
> 	print $~bar
> 
> Completely unexpected results.
> 
> Also it seriously breaks sh compatibility, so at the very least it should
> be disabled when SH_GLOB or similar options are in effect.
> 
> There's a reason that only **/ and not blather**/ is special.

Then there's a problem with **/ :

  foo='*'
  print ${~foo}*/

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
100% validated (X)HTML - Acorn / RISC OS / ARM, free software, YP17,
Championnat International des Jeux Mathématiques et Logiques, etc.
Work: CR INRIA - computer arithmetic / SPACES project at LORIA