do &function -- unexpected behavior

[p5pRT]

Migrated from rt.perl.org#5973 (status was 'resolved')

Searchable as RT5973$

[p5pRT]

From [email protected]

jeffp@​hut [1​:00am] ~ #102> perl -w
sub foo { print "ok\n"; 123 }
do &foo;
ok
Perl v123.0.0 required--this is only v5.6.0, stopped (did you mean
v123.0.0?) at - line 2.

I do NOT know what to make of that. It seems like Perl interprets the
return value of a 'do &foo' as something to send to 'use' for a version
number. But what do you make of​:

jeffp@​hut [1​:02am] ~ #105> perl -w
sub foo { print 1 }
do &foo;
Perl v49.0.679940 required--this is only v5.6.0, stopped at - line 2.
1

That is bizarre.

Perl Info

Flags:
    category=core
    severity=medium

Site configuration information for perl v5.6.0:

Configured by robsiemb at Wed Jun 28 15:35:19 EDT 2000.

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
  Platform:
    osname=freebsd, osvers=2.2.8-release, archname=i386-freebsd
    uname='freebsd hut.crusoe.net 2.2.8-release freebsd 2.2.8-release #0: fri sep 3 10:23:22 edt 1999 [email protected]:usrsrcsyscompilehut i386 '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define 
    use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef
  Compiler:
    cc='gcc', optimize='-O', gccversion=2.7.2.1
    cppflags='-I/usr/local/include'
    ccflags ='-I/usr/local/include'
    stdchar='char', d_stdstdio=undef, usevfork=true
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='ld', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib
    libs=-lm -lc -lcrypt
    libc=/usr/lib/libc.so.3.1, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-DPIC -fpic', lddlflags='-Bshareable  -L/usr/local/lib'

Locally applied patches:
    


@INC for perl v5.6.0:
    /usr/local/lib/perl5/5.6.0/i386-freebsd
    /usr/local/lib/perl5/5.6.0
    /usr/local/lib/perl5/site_perl/5.6.0/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.6.0
    /usr/local/lib/perl5/site_perl/5.005/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.005
    /usr/local/lib/perl5/site_perl
    .


Environment for perl v5.6.0:
    HOME=/home/jeffp
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/usr/bin:/usr/ucb:/usr/sbin:/usr/openwin/bin:/bin:/crusoe/appl/bin:/usr/local/netscape:/usr/ccs/bin:.:/home/jeffp/utils:/home/jeffp/bin
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/tcsh

[p5pRT]

From [Unknown Contact. See original ticket]

On Mar 6, jeffp@​hut.crusoe.net said​:

This is a bug report for perl from japhy@​pobox.com,
generated with the help of perlbug 1.28 running under perl v5.6.0.

-----------------------------------------------------------------
[Please enter your report here]

jeffp@​hut [1​:00am] ~ #102> perl -w
sub foo { print "ok\n"; 123 }
do &foo;
ok
Perl v123.0.0 required--this is only v5.6.0, stopped (did you mean
v123.0.0?) at - line 2.

I do NOT know what to make of that. It seems like Perl interprets the
return value of a 'do &foo' as something to send to 'use' for a version
number. But what do you make of​:

jeffp@​hut [1​:02am] ~ #105> perl -w
sub foo { print 1 }
do &foo;
Perl v49.0.679940 required--this is only v5.6.0, stopped at - line 2.
1

That is bizarre.

It also occurs with​:

  $foo = sub { print 123 };
  do $foo->(); # odd Perl version message
  do &$foo; # odd Perl version message

(YES, I know do() for functions is deprecated.)

This is related, at least in the parsing aspect, to the UNTOUCHED bug
involving​:

  do(q(foo));
  # vs.
  do q(foo) ;

The first works, and tries to execute 'foo'. The second fails, and tries
to call the function &q. The parser mis-interprets a q, qq, qx, qr, or qw
after a 'do'.

[p5pRT]

From @tamias

On Tue, Mar 06, 2001 at 01​:06​:10AM -0500, jeffp@​hut.crusoe.net wrote​:

jeffp@​hut [1​:00am] ~ #102> perl -w
sub foo { print "ok\n"; 123 }
do &foo;
ok
Perl v123.0.0 required--this is only v5.6.0, stopped (did you mean
v123.0.0?) at - line 2.

I do NOT know what to make of that. It seems like Perl interprets the
return value of a 'do &foo' as something to send to 'use' for a version
number.

FYI​:

% perl -e 'do 123'
Perl 123 required--this is only version 5.00503, stopped at -e line 1.

% cat tmp
print "Hello world!\n";
% perl -e 'do tmp'
Hello world!
% perl -e 'sub foo { "tmp" } do &foo'
Hello world!

do &foo is being interpreted as do EXPR, not as do SUBROUTINE, which has
been the case since 5.005_03 if not earlier.

Ronald