[perl #24212] non-defined -x tests behaviour unexpected ( "-1" eq -F 1' )

# New Ticket Created by  David Dyck 
# Please include the string:  [perl #24212]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=24212 >



This is a bug report for perl from david.dyck@fluke.com,
generated with the help of perlbug 1.34 running under perl v5.9.0.


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[Please enter your report here]

I had a error in some code the other day, when
I intended to code -f but instead I entered -F.

To my surprise, I didn't get an error or warning.

After reading toke.c in the perl sources, I see 
the following comment when the letter after the '-' in -x
is not one those listed in perldoc -f -x

    /* Assume it was a minus followed by a one-letter named
     * subroutine call (or a -bareword), then. */

In perlop.pod


    Unary "-" performs arithmetic negation if the operand is numeric. If the
    operand is an identifier, a string consisting of a minus sign concatenated
    with the identifier is returned. Otherwise, if the string starts with a
    plus or minus, a string starting with the opposite sign is returned. One
    effect of these rules is that "-bareword" is equivalent to "-bareword".

  [ perhaps the text above could be written differently, as
    "-bareword" is alwasy equal to "-bareword",  (I do see that
    the pod source encodes this differently, as
      C<-bareword> is equivalent to C<"-bareword">
    which in html displays as
      -bareword is equivalent to "-bareword". ]

Anyway, I expect that perl should give me an error, a warning,
or return a bareword converted string, but in the following
examples perl is definitely DWIM'ing

If I create a one-letter subroutine I see that the sub is not called:

$ perl -wle 'use strict; print -F 1'
-1

And the -F is not converted to a -bareword

$ perl -wle 'use strict; print -F 1'
-1

$ perl -wle 'use strict; print "strange" if "-1" eq -F 1'
strange


The follow scripts reports the set of letters where -x doesn't
do what I expect.
  e.g. strange -X codes: DEFGHIJKLNOPQUVYZahijmnoqvy


#!/usr/local/bin/perl -w

use strict;
no strict 'refs';
use B::Deparse;
my $d=B::Deparse->new();
my $q = "1"; 
my @testlist = ("a" .."z", "A" .. "Z");
my %strange;
for my $x (@testlist) {
    my $s =  "{\n    -$x \$q;\n}";
    my $sr = eval "sub $s"; 
    warn "$@" if length $@; 

    my $dp = $d->coderef2text( $sr ); 
    if ($s ne $dp) { 
	print "expect:\n$s\ndeparse returned:\n$dp\n"; 
	++$strange{$x}
    } 
} 
print "strange -X codes: ",join( "", sort keys %strange), "\n";
__END__



[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=low
---
Site configuration information for perl v5.9.0:

Configured by dcd at Tue Oct  7 12:13:57 PDT 2003.

Summary of my perl5 (revision 5.0 version 9 subversion 0 patch 21419) configuration:
  Platform:
    osname=linux, osvers=2.4.23pre1, archname=i686-linux
    uname='linux dd 2.4.23pre1 #2 wed aug 27 11:20:37 pdt 2003 i686 '
    config_args='-Dmksymlinks -Dinstallusrbinperl -Uversiononly -Dusedevel -Doptimize=-O3 -g -de -Dcf_email=david.dyck@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:
    DEVEL21398

---
@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

• [perl #24212] non-defined -x tests behaviour unexpected ( "-1" eq -F 1' ) by David Dyck
• Re: [perl #24212] non-defined -x tests behaviour unexpected ( "-1" eq -F 1' ) by Rafael Garcia-Suarez