[BusyBox 0000914]: awk/gawk incompatibility: busybox includes POSIX interval expressions by default

[bugs at busybox.net]

The following issue has been CLOSED 
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http://busybox.net/bugs/view.php?id=914 
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Reported By:                vda2
Assigned To:                BusyBox
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Project:                    BusyBox
Issue ID:                   914
Category:                   Documentation
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     closed
Resolution:                 won't fix
Fixed in Version:           
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Date Submitted:             06-20-2006 08:47 PDT
Last Modified:              06-20-2006 16:18 PDT
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Summary:                    awk/gawk incompatibility: busybox includes POSIX
interval expressions by default
Description: 
bbox's awk -f <this file> says: "awk: xregcomp: Unmatched \{"
gawk-3.0.4 doesn't
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---------------------------------------------------------------------- 
 vapier - 06-20-06 16:18  
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this is because gawk's default regular expression support includes all
POSIX expressions *except* interval expressions

busybox's regular expression support includes all POSIX expressions
including internal expressions ... which means you need to escape the {

if you read the SUSv3 standards, busybox's behavior is compliant:
http://www.opengroup.org/onlinepubs/009695399/utilities/awk.html
http://www.opengroup.org/onlinepubs/009695399/utilities/awk.html#tag_04_06_13_04
 * Regular Expressions
   The awk utility shall make use of the extended regular expression
notation (see the Base Definitions volume of IEEE Std 1003.1-2001, Section
9.4, Extended Regular Expressions)

http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04_03
   The asterisk, plus-sign, question-mark, and left-brace shall be special
except when used in a bracket expression.

and in fact, the standard says that doing '\{' should always result in
matching of a '{'
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_03_02

so, since you arent using [{], and you arent using '\{', your code is not
portable and busybox makes no promise that it will work 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
06-20-06 08:47  vda2           New Issue                                    
06-20-06 08:47  vda2           Status                   new => assigned     
06-20-06 08:47  vda2           Assigned To               => BusyBox         
06-20-06 08:47  vda2           File Added: addsym.awk                       
06-20-06 09:15  vda            Issue Monitored: vda                         
06-20-06 16:18  vapier         Note Added: 0001436                          
06-20-06 16:18  vapier         Status                   assigned => closed  
06-20-06 16:18  vapier         Resolution               open => won't fix   
06-20-06 16:18  vapier         Summary                  awk/gawk incompatibility
(testcase included) => awk/gawk incompatibility: busybox includes POSIX interval
expressions by default
======================================================================