0_ gives double warning

[p5pRT]

Migrated from rt.perl.org#70878 (status was 'open')

Searchable as RT70878$

[p5pRT]

From frank.wiegand@gmail.com

This is a bug report for perl from frank.wiegand@​gmail.com,
generated with the help of perlbug 1.39 running under perl 5.10.1.

---

  % perl -we 0_
  Misplaced _ in number at -e line 1.
  Misplaced _ in number at -e line 1.

Occurs only with 0_, not 1_ or else.

The doubled warning still resides in 5.11.2.

Frank

---

---

Flags​:
  category=core
  severity=low

---

Site configuration information for perl 5.10.1​:

Configured by Debian Project at Sat Nov 7 22​:18​:45 UTC 2009.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration​:
 
  Platform​:
  osname=linux, osvers=2.6.31.5-dsa-amd64, archname=x86_64-linux-gnu-thread-multi
  uname='linux brahms 2.6.31.5-dsa-amd64 #1 smp fri oct 23 12​:25​:24 cest 2009 x86_64 gnulinux '
  config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.10.1 -Dsitearch=/usr/local/lib/perl/5.10.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.10.1 -Dd_dosuid -des'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=define, usemultiplicity=define
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=define, use64bitall=define, uselongdouble=undef
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
  optimize='-O2 -g',
  cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
  ccversion='', gccversion='4.3.4', gccosandvers=''
  intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
  ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
  alignbytes=8, prototype=define
  Linker and Libraries​:
  ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
  libpth=/usr/local/lib /lib /usr/lib /lib64 /usr/lib64
  libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
  perllibs=-ldl -lm -lpthread -lc -lcrypt
  libc=/lib/libc-2.10.1.so, so=so, useshrplib=true, libperl=libperl.so.5.10.1
  gnulibc_version='2.10.1'
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
  cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector'

Locally applied patches​:
 

---

@​INC for perl 5.10.1​:
  /etc/perl
  /usr/local/lib/perl/5.10.1
  /usr/local/share/perl/5.10.1
  /usr/lib/perl5
  /usr/share/perl5
  /usr/lib/perl/5.10
  /usr/share/perl/5.10
  /usr/local/lib/site_perl
  .

---

Environment for perl 5.10.1​:
  HOME=/home/fw
  LANG=de_DE.UTF-8
  LANGUAGE=
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/sbin​:/usr/sbin​:/home/fw/bin​:/home/fw/bin​:/usr/local/bin​:/usr/bin​:/bin​:/usr/games
  PERL_AUTOINSTALL=--defaultdeps
  PERL_BADLANG (unset)
  PERL_EXTUTILS_AUTOINSTALL=--defaultdeps
  PERL_MM_USE_DEFAULT=1
  SHELL=/bin/zsh

[p5pRT]

From p5p@spam.wizbit.be

On Fri Nov 27 06​:26​:16 2009, frank.wiegand wrote​:

This is a bug report for perl from frank.wiegand@​gmail.com,
generated with the help of perlbug 1.39 running under perl 5.10.1.

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

% perl -we 0_
Misplaced _ in number at -e line 1.
Misplaced _ in number at -e line 1.

Occurs only with 0_, not 1_ or else.

The doubled warning still resides in 5.11.2.

Frank

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

What is happening in the code​:

a) first it checks if the (octal) number begins with '_'
b) then it checks the next charachters to see if they are valid (not
the case so the parsing ends)
c) then it checks if the last character was '_'.

In this case there is only one character and this produces the warning
(because '_' is not valid at the start of a number nor at the end of a
number).

The double warning also happens in the following cases​:
  print 0x_;
  print 0b_;
  print 5._;

The double warning does not happen for​:
  print 5e_;

The reason for this is that the parsing of the exponent is a bit
different​:

a) it checks if the first character is '_'
b) it checks if the second character is '+' or '-'
c) it checks if the third character is _

This also means that​: print 5e__-3 is parsed as​: 5 - 3 (= 2) and not as
5e-3 (0.005).

The only fix I can currently see is to add another var which contains
the 'real start' of the number...

Best regards,

Bram

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

From zefram@fysh.org

Fixed in 72c80c7.

-zefram

[khwilliamson]

Confirmed that is fixed