.. operator

[p5pRT]

Migrated from rt.perl.org#1929 (status was 'resolved')

Searchable as RT1929$

[p5pRT]

From ashted@southern.edu

bash$ cat x

for (1) {
  print scalar($_ .. 0),"\n";
  print scalar(1 .. 0),"\n";
}
bash$ perl x
1

bash$ perl -V
Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration​:
  Platform​:
  osname=linux, osvers=2.2.1-ac1, archname=i386-linux
  uname='linux porky.devel.redhat.com 2.2.1-ac1 #1 smp mon feb 1 17​:44​:44 est
1999 i686 unknown '
  hint=recommended, useposix=true, d_sigaction=define
  usethreads=undef useperlio=undef d_sfio=undef
  Compiler​:
  cc='cc', optimize='-O2', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2
release)
  cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
  ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
  stdchar='char', d_stdstdio=undef, usevfork=false
  intsize=4, longsize=4, ptrsize=4, doublesize=8
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
  alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries​:
  ld='cc', ldflags =' -L/usr/local/lib'
  libpth=/usr/local/lib /lib /usr/lib
  libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
  libc=, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
  cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Characteristics of this binary (from libperl)​:
  Built under linux
  Compiled at Apr 6 1999 23​:34​:07
  @​INC​:
  /usr/lib/perl5/5.00503/i386-linux
  /usr/lib/perl5/5.00503
  /usr/lib/perl5/site_perl/5.005/i386-linux
  /usr/lib/perl5/site_perl/5.005
  .

Thanks,
Ted

[p5pRT]

From @tamias

On Tue, Dec 21, 1999 at 12​:31​:43PM -0500, Ted Ashton wrote​:

Am I missing something here?

bash$ cat x

for (1) {
print scalar($_ .. 0),"\n";
print scalar(1 .. 0),"\n";
}
bash$ perl x
1

Yes.

perldoc perlop​:

  If either operand of scalar ".." is a
  constant expression, that operand is implicitly compared
  to the $. variable, the current line number.

1 is a constant expression. $_ is not.

Ronald

[p5pRT]

From [Unknown Contact. See original ticket]

Am I missing something here?

bash$ cat x

for (1) {
print scalar($_ .. 0),"\n";
print scalar(1 .. 0),"\n";
}
bash$ perl x
1

bash$ perl -V
...

What you're missing is that $. never went ==1. In the
second case, you're not going to be true until that happens.

--tom