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/x does not ignore commented slashes. #2037

Closed p5pRT closed 21 years ago

p5pRT commented 24 years ago

Migrated from rt.perl.org#3315 (status was 'resolved')

Searchable as RT3315$

p5pRT commented 24 years ago

From krolnik@lsil.com

This is a bug report for perl from krolnik@​lsil.com\, generated with the help of perlbug 1.26 running under perl 5.00503.

# Here are three forms of regular expressions # that should only be differing by whitespace.

$a =~ s/c|d|e//x;

$a1 =~ s/c #   |d # here \   |e //x;

# The above two do fine - parse correctly.

$a2 =~ s/c # /   |d # here \   |e //x;

This similar example (differing in 1 character) causes parsing problems. perl (5.00503 and 5.6 ) -wc produces (among others)

Unquoted string "x" may clash with future reserved word at /tmp/spl line 16.

The slash at the end of the first line of the regular expression terminates the regular expression - incorrectly.

Site configuration information for perl 5.00503​:

Configured by greg at Thu Oct 7 17​:35​:08 CDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration​:   Platform​:   osname=solaris\, osvers=2.6\, archname=sun4-solaris   uname='sunos dts49 5.6 generic_105181-15 sun4u sparc sunw\,ultra-enterprise '   hint=previous\, useposix=true\, d_sigaction=define   usethreads=undef useperlio=undef d_sfio=undef   Compiler​:   cc='gcc'\, optimize='-O'\, gccversion=2.8.1   cppflags='-I/usr/local/include'   ccflags ='-I/usr/local/include'   stdchar='unsigned char'\, d_stdstdio=define\, usevfork=false   intsize=4\, longsize=4\, ptrsize=4\, doublesize=8   d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=16   alignbytes=8\, usemymalloc=y\, prototype=define   Linker and Libraries​:   ld='gcc'\, ldflags =' -L/usr/local/lib'   libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib   libs=-lsocket -lnsl -ldl -lm -lc -lcrypt   libc=/lib/libc.so\, so=so\, useshrplib=false\, libperl=libperl.a   Dynamic Linking​:   dlsrc=dl_dlopen.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags=' '   cccdlflags='-fPIC'\, lddlflags='-G -L/usr/local/lib'

Locally applied patches​:  

@​INC for perl 5.00503​:   /design/db/lib/perl   /usr/local/apps/perl/5.005_03/lib/5.00503/sun4-solaris   /usr/local/apps/perl/5.005_03/lib/5.00503   /usr/local/apps/perl/5.005_03/lib/site_perl/5.005/sun4-solaris   /usr/local/apps/perl/5.005_03/lib/site_perl/5.005   .

Environment for perl 5.00503​:   HOME=/user/krolnik   LANG=C   LANGUAGE (unset)   LD_LIBRARY_PATH=/usr/local/lib​:/usr/openwin/lib​:/tools/lsi_fs/2.0/arch/SunOS-5.7​:/tools/cadence/4.42/tools/lib​:/tools/cadence/4.42/tools/leapfrog/lib​:/tools/cadence/4.42/tools/verilog/lib​:/tools/summit/hdlscore/2.0.5/SunOS5/lib​:/user/krolnik/lib​:/usr/local/lib/X11   LOGDIR (unset)   PATH=/usr/dt/bin​:.​:/usr/openwin/bin​:/bin​:/usr/bin​:/usr/ucb​:/usr/sbin​:/usr/dt/bin​:/tools/flex/bin​:/usr/local/bin​:/user/krolnik/bin​:.​:/usr/ccs/bin​:/usr/ccs/lib​:/tools/frame/5.5.3/bin​:/tools/uslsiapp/3.0/shared​:/tools/uslsiapp/3.0/bin/sunv​:/tools/askk/5.0/common/bin​:/tools/lsi_fs/2.0/bin/SunOS-5.7​:/tools/cadence/4.42/tools/bin​:/tools/lsf/3.2/bin​:/tools/modeltech/5.3a/bin​:/design/db/com​:/design/db/blaze/com​:/design/db/blaze/bin​:/tools/Razor/Razor/bin​:/tools/Razor/Razor/scripts​:/design/db/blaze/.RAZORDB/403DB/RAZOR_UNIVERSE/Scripts​:/design/db/blaze/source/zsp_tools/sdspI/bin​:/design/db/blaze/work/z16402/bin​:/tools/debussy//4.4/bin​:/tools/summit/hdlscore/2.0.5/bin​:/design/db/blaze/com​:/design/db/blaze/bin​:/usr/openwin/bin​:/user/krolnik/bin   PERL5LIB=/design/db/lib/perl   PERL_BADLANG (unset)   SHELL (unset)

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

This is a bug report for perl from krolnik@​lsil.com\, generated with the help of perlbug 1.26 running under perl 5.00503.

# Here are three forms of regular expressions # that should only be differing by whitespace.

$a =~ s/c|d|e//x;

$a1 =~ s/c #   |d # here \   |e //x;

# The above two do fine - parse correctly.

$a2 =~ s/c # /   |d # here \   |e //x;

This similar example (differing in 1 character) causes parsing problems. perl (5.00503 and 5.6 ) -wc produces (among others)

Unquoted string "x" may clash with future reserved word at /tmp/spl line 16.

The slash at the end of the first line of the regular expression terminates the regular expression - incorrectly.

Site configuration information for perl 5.00503​:

Configured by greg at Thu Oct 7 17​:35​:08 CDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration​:   Platform​:   osname=solaris\, osvers=2.6\, archname=sun4-solaris   uname='sunos dts49 5.6 generic_105181-15 sun4u sparc sunw\,ultra-enterprise '   hint=previous\, useposix=true\, d_sigaction=define   usethreads=undef useperlio=undef d_sfio=undef   Compiler​:   cc='gcc'\, optimize='-O'\, gccversion=2.8.1   cppflags='-I/usr/local/include'   ccflags ='-I/usr/local/include'   stdchar='unsigned char'\, d_stdstdio=define\, usevfork=false   intsize=4\, longsize=4\, ptrsize=4\, doublesize=8   d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=16   alignbytes=8\, usemymalloc=y\, prototype=define   Linker and Libraries​:   ld='gcc'\, ldflags =' -L/usr/local/lib'   libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib   libs=-lsocket -lnsl -ldl -lm -lc -lcrypt   libc=/lib/libc.so\, so=so\, useshrplib=false\, libperl=libperl.a   Dynamic Linking​:   dlsrc=dl_dlopen.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags=' '   cccdlflags='-fPIC'\, lddlflags='-G -L/usr/local/lib'

Locally applied patches​:  

@​INC for perl 5.00503​:   /design/db/lib/perl   /usr/local/apps/perl/5.005_03/lib/5.00503/sun4-solaris   /usr/local/apps/perl/5.005_03/lib/5.00503   /usr/local/apps/perl/5.005_03/lib/site_perl/5.005/sun4-solaris   /usr/local/apps/perl/5.005_03/lib/site_perl/5.005   .

Environment for perl 5.00503​:   HOME=/user/krolnik   LANG=C   LANGUAGE (unset)  
LD_LIBRARY_PATH=/usr/local/lib​:/usr/openwin/lib​:/tools/lsi_fs/2.0/arch/SunOS-5.7​:/tools/cadence/4.42/tools/lib​:/tools/cadence/4.42/tools/leapfrog/lib​:/tools/cadence/4.42/tools/verilog/lib​:/tools/summit/hdlscore/2.0.5/SunOS5/lib​:/user/krolnik/lib​:/usr/local/lib/X11   LOGDIR (unset)  
PATH=/usr/dt/bin​:.​:/usr/openwin/bin​:/bin​:/usr/bin​:/usr/ucb​:/usr/sbin​:/usr/dt/bin​:/tools/flex/bin​:/usr/local/bin​:/user/krolnik/bin​:.​:/usr/ccs/bin​:/usr/ccs/lib​:/tools/frame/5.5.3/bin​:/tools/uslsiapp/3.0/shared​:/tools/uslsiapp/3.0/bin/sunv​:/tools/askk/5.0/common/bin​:/tools/lsi_fs/2.0/bin/SunOS-5.7​:/tools/cadence/4.42/tools/bin​:/tools/lsf/3.2/bin​:/tools/modeltech/5.3a/bin​:/design/db/com​:/design/db/blaze/com​:/design/db/blaze/bin​:/tools/Razor/Razor/bin​:/tools/Razor/Razor/scripts​:/design/db/blaze/.RAZORDB/403DB/RAZOR_UNIVERSE/Scripts​:/design/db/blaze/source/zsp_tools/sdspI/bin​:/design/db/blaze/work/z16402/bin​:/tools/debussy//4.4/bin​:/tools/summit/hdlscore/2.0.5/bin​:/design/db/blaze/com​:/design/db/blaze/bin​:/usr/openwin/bin​:/user/krolnik/bin   PERL5LIB=/design/db/lib/perl   PERL_BADLANG (unset)   SHELL (unset)

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

This is a bug report for perl from krolnik@​lsil.com\, generated with the help of perlbug 1.26 running under perl 5.00503.

$a =~ s/c|d|e//x;

$a1 =~ s/c # |d # here \ |e //x;

# The above two do fine - parse correctly.

$a2 =~ s/c # / |d # here \ |e //x;

Unquoted string "x" may clash with future reserved word at /tmp/spl line 16.

All is correct - you try to divide s/// by x. s/// / x; is probably not what you want.

Vadim.

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

Annoying\, but as documented​: see the perlre man page. Basically\, perl's main parser\, which knows nothing about the effects of the /x flag\, uses the chosen regex delimiter to decide what to hand off to the specialized regex parser. The regex parser subsequently uses the /x flag\, if present\, to modify the way in which it parses what it's been handed. Fixing the small niggle you've stumbled across would require modifying the main parser to find and interpret the /x flag. It was decided a long time ago that the gain was not worth the pain.

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

Dominic Dunlop \domo@​computer\.org wrote

Fixing the small niggle you've stumbled across would require modifying the main parser to find and interpret the /x flag. It was decided a long time ago that the gain was not worth the pain.

It's worse than that. Examples of this sort are actually ambiguous\, and regexes existed long before the /x switch. So backwards compatibility precludes "fixing" anything.

Mike Guy

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

"Fixing" this is not just not a case where the gain is not worth the pain\, it is a case where the *pain* is not worth the pain!

Consider the following code​:

if ($foo =~ /#/) {   # Do something } # Time passes print "eg. In DOS you would use /x instead of -x\n";

How should that be parsed?

Cheers\, Ben

p5pRT commented 21 years ago

From @iabyn

not-a-bug

p5pRT commented 21 years ago

@iabyn - Status changed from 'open' to 'resolved'