[perl #23131] warning from perl faq that strips C and C++ comments

[dcd - Sat Jul 26 11:38:47 2003]:

> 
> This is a bug report for perl from david.dyck <!--c--> <i>at</i>
<!--a--> fluke.com,
> generated with the help of perlbug 1.34 running under perl v5.9.0.
> 
> 
> -----------------------------------------------------------------
> [Please enter your report here]
> 
> I would think that the examples in the perl faq
> should be "warning clean", unless otherwize noted,
> or obvious from the context?
> 
> When I use the code directly from the perlfaq to remove comments
> (including C++ comments) from perlfaq6.pod
> 
s#/\*[^*]*\*+([^/*][^*]*\*+)*/|//[^\n]*|("(\\.|[^"\\])*"|'(\\.|[^'\\])*'|.[^/"'\\]*)#$2#gs;
> as the source of the perl program using perl -w ( I actually used perl
> -pwl and use the expression as the whole program) I get warnings when
> it removes both C and C++ comments from input lines.
> 
> My work around is to add a
> 	no warnings qw(uninitialized);
> line around the substitution that triggers the warning.
> 
> Even the Fred Curtis's expanded expression triggers the warning.
> 
> Perhaps a note in that faq to suggest that the user may
> want to add the above no warnings line would be appropriate.
> 

Or just check the definedness of $2, like in the attached patch.
This also fixes a missing ";" in the first code example.

Regards,
    Slaven



> [Please do not change anything below this line]
> -----------------------------------------------------------------
> ---
> Flags:
>     category=docs
>     severity=medium
> ---
> Site configuration information for perl v5.9.0:
> 
> Configured by dcd at Tue Jul 22 08:31:10 PDT 2003.
> 
> Summary of my perl5 (revision 5.0 version 9 subversion 0 patch 20179)
>    configuration:
>   Platform:
>     osname=linux, osvers=2.4.22-pre7, archname=i686-linux
>     uname='linux dd 2.4.22-pre7 #4 sat jul 19 18:40:10 pdt 2003 i686 '
>     config_args='-Dmksymlinks -Dinstallusrbinperl -Uversiononly
>    -Dusedevel -Doptimize=-O3 -g -de -Dcf_email=david.dyck <!--c-->
<i>at</i> <!--a--> fluke.com'
>     hint=recommended, useposix=true, d_sigaction=define
>     usethreads=undef useithreads=undef usemultiplicity=undef
>     useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
>     use64bitint=undef use64bitall=undef uselongdouble=undef
>     usemymalloc=n, bincompat5005=undef
>   Compiler:
>     cc='cc', ccflags ='-DDEBUGGING -fno-strict-aliasing
>    -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
>     optimize='-O3 -g',
>     cppflags='-DDEBUGGING -fno-strict-aliasing -I/usr/local/include'
>     ccversion='', gccversion='egcs-2.91.66.1 19990314/Linux (egcs-
>    1.1.2 release)', gccosandvers=''
>     intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
>     d_longlong=define, longlongsize=8, d_longdbl=define,
>    longdblsize=12
>     ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
>    lseeksize=4
>     alignbytes=4, prototype=define
>   Linker and Libraries:
>     ld='cc', ldflags =' -L/usr/local/lib'
>     libpth=/usr/local/lib /lib /usr/lib
>     libs=-lgdbm -ldbm -ldb -ldl -lm -lc
>     perllibs=-ldl -lm -lc
>     libc=/lib/libc.so.5.4.44, so=so, useshrplib=false,
>    libperl=libperl.a
>     gnulibc_version=''
>   Dynamic Linking:
>     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-
>    rdynamic'
>     cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'
> 
> Locally applied patches:
>     DEVEL20173
> 
> ---
> @INC for perl v5.9.0:
>     /usr/local/lib/perl5/5.9.0/i686-linux
>     /usr/local/lib/perl5/5.9.0
>     /usr/local/lib/perl5/site_perl/5.9.0/i686-linux
>     /usr/local/lib/perl5/site_perl/5.9.0
>     /usr/local/lib/perl5/site_perl/5.8.0/i686-linux
>     /usr/local/lib/perl5/site_perl/5.8.0
>     /usr/local/lib/perl5/site_perl
>     .
> 
> ---
> Environment for perl v5.9.0:
>     HOME=/home/dcd
>     LANG (unset)
>     LANGUAGE (unset)
>     LD_LIBRARY_PATH (unset)
>     LOGDIR (unset)
>    
PATH=/home/dcd/bin:/sbin:/usr/local/bin:/bin:/usr/bin:/usr/X11/bin:/usr/games:/usr/local/samba:/home/hobbes/tools/scripts:/home/hobbes/tools/linux:/usr0/hobbes/tools/scripts:/usr0/dcd/bin:/apps/general/bin:/usr/public
>     PERL5_CPANPLUS_CONFIG=/home/dcd/.cpanplus/config
>     PERL_BADLANG (unset)
>     SHELL=/bin/bash