[Tcl-bugs] [ tcl-Bugs-578363 ] [:xdigit:] makes RE to behave strange

[<no...@so...>]

Bugs item #578363, was opened at 2002-07-07 21:31
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=578363&group_id=10894

Category: 41. Regexp
Group: None
Status: Open
Resolution: None
Priority: 6
Submitted By: Pavel Goran (pvgoran)
Assigned to: Nobody/Anonymous (nobody)
Summary: [:xdigit:] makes RE to behave strange

Initial Comment:
Tcl Version: 8.4a3

Platform: Windows

Code 
sample:
set str {2:::DebugWin32}
set re 
{([[:xdigit:]])([[:space:]]*)}
puts "[regexp $re $str match xdigit 
spaces]"
puts "match=$match"
puts 
"xdigit=$xdigit"
puts "spaces=$spaces"

This 
gives:
1
match=2:::DebugWin32
xdigit=2
spaces=:::DebugWin32

Observed 
behaviour: "spaces=:::DebugWin32"

Desired behaviour: 
"spaces="

Comment:
It looks like the [[:xdigit:]] 
bracket expression causes the [[:space:]] bracket expression to 
match any symbol.

If [[:xdigit:]] is replaced, for example, 
by [[:digit:]], or [[:space:]] is replaced by [[:alpha:]], all is going 
right. (Initially, I noticed this problem with \s instead of 
[[:space:]].)


----------------------------------------------------------------------

>Comment By: Pavel Goran (pvgoran)
Date: 2002-07-28 23:42

Message:
Logged In: YES 
user_id=383758

Yes, I definitely had to attach the files, since inserting them into the 
comment text give very strange formatting. Is this a bug in 
SourceForge.net software, or it is caused by my Opera browser? :)


----------------------------------------------------------------------

Comment By: Pavel Goran (pvgoran)
Date: 2002-07-28 23:31

Message:
Logged In: YES 
user_id=383758

This bug is caused by the error in generic/regc_cvec.c.

Patch for: 
File "generic/regc_cvec.c", Branch "MAIN", Revision 1.4

--- 
regc_cvec.c	Sun Jul 28 22:34:17 2002
+++ 
regc_cvec.c.new	Sun Jul 28 23:15:34 2002
@@ -50,7 +50,7 
@@
 	cv = (struct cvec *)MALLOC(n);
 	if (cv == NULL)
 
		return NULL;
-	cv->chrspace = nc;
+	cv->chrspace = 
nchrs;
 	cv->chrs = (chr *)&cv->mcces[nmcces];	/* chrs just after 
MCCE ptrs */
 	cv->mccespace = nmcces;
 	cv->ranges = cv-
>chrs + nchrs + nmcces*(MAXMCCE+1);

It's strange that such 
a serious error was not noticed yet.

I also found the inconsistency 
in generic/regc_locale.c. The existing code should work without 
problems, but it is not correct. It can be fixed in two ways. The first 
one:

Patch for: File "generic/regc_locale.c", Branch "MAIN", 
Revision 1.8

--- regc_locale.c	Sun Jul 28 22:33:28 2002
+++ 
regc_locale.c.new-1	Sun Jul 28 22:38:02 2002
@@ -842,7 
+842,10 @@
 	case CC_XDIGIT:
 	    cv = getcvec(v, 0, 
NUM_DIGIT_RANGE+2, 0);
 	    if (cv) {	
-		addrange(cv, '0', 
'9');
+		for (i = 0; i < NUM_DIGIT_RANGE; i++) {
+		    
addrange(cv, digitRangeTable[i].start,
+			    
digitRangeTable[i].end);
+		}
 		addrange(cv, 'a', 'f');
 
		addrange(cv, 'A', 'F');
 	    }

The second one:

Patch 
for: File "generic/regc_locale.c", Branch "MAIN", Revision 1.8

--- 
regc_locale.c	Sun Jul 28 22:33:28 2002
+++ regc_locale.c.new-
2	Sun Jul 28 23:15:03 2002
@@ -840,7 +840,7 @@
 	    }
 	    
break;
 	case CC_XDIGIT:
-	    cv = getcvec(v, 0, 
NUM_DIGIT_RANGE+2, 0);
+	    cv = getcvec(v, 0, 3, 0);
 	    if (cv) 
{	
 		addrange(cv, '0', '9');
 		addrange(cv, 'a', 'f');

The 
first way is IMO preferrable.

P.S. Maybe it was better to attach 
three diff files, instead of inserting them in the text?


----------------------------------------------------------------------

Comment By: Donal K. Fellows (dkf)
Date: 2002-07-08 16:49

Message:
Logged In: YES 
user_id=79902

Strange indeed!  If only the RE engine was less cryptic...

Suggested workaround: replace [[:xdigit:]] with [0-9a-fA-F]
which works.

----------------------------------------------------------------------

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