'g' flag w/'qr'

[perl-diddler]

I was trying a few examples from the "Mastering Perl" (brian d foy) book relating to RE's. I noted w/interest, the 3 ways he used to match a "qr" expression on page 3.

sub iregex { qr/ ... /ix }

1)  my $regex = iregex()
    if ($isbn =~ m/$regex/ ) { print "Matched!\n }

2)  my $regex = iregex()
    if ($isbn =~ $regex ) { print "Matched!\n }

3)  if ($isbn =~ iregex() ) { print "Matched!\n }

I especially liked methods 2 & 3 as they didn't need interpolation, with 3 being better as it didn't require an intermediate variable.

Seeing that I wanted to try out capturing all matching sub expressions using 'g' added to my 'qr' expression, but I'm getting a deprecation error:

> perl -we'use strict;use P;      
my $re = qr{ (\w+) }gx;
my $dat = "Just another cats meow";
my @matches = $dat =~ $re;
P "#matches=%s, matches=%s", scalar(@matches), \@matches;
exit scalar(@matches);'
  output:
Having no space between pattern and following word is deprecated at -e
+ line 2.
Bareword found where operator expected at -e line 2, near "qr/ (\w+) /
+gx"
syntax error at -e line 2, near "qr{ (\w+) }gx"
Execution of -e aborted due to compilation errors.

If I move the 'g' option down to where the RE is used and use a *second* "RE" operator (i.e.: /.../g) and interpolate my expression into another RE (the slowest of the above 3 options), I get:

> perl -we'use strict;use P;      
my $re = qr{ (\w+) }x; 
my $dat = "Just another cats meow";
my @matches = $dat =~ /$re/g;
P "#matches=%s, matches=%s", scalar(@matches), \@matches;
exit scalar(@matches);'
  output:
#matches=4, matches=["Just", "another", "cats", "meow"]

So why can't I add the global switch to the "qr" expression? FWIW, I also tried qr{ (?xg) }. Perl strips out the 'g' and tells me to add it to the end of the RE -- where it is deprecated:

perl -we'use strict;use P;      
my $re = qr{ (?xg) (\w+) };
my $dat = "Just another cats meow";
my @matches = $dat =~ $re;   
P "#matches=%s, matches=%s", scalar(@matches), \@matches;
exit scalar(@matches);'
  output:
Useless (?g) - use /g modifier in regex; marked by <-- HERE in m/ (?xg
+ <-- HERE ) (\w+) / at -e line 2.
#matches=1, matches=["another"]

So how can I attach the "/g" modifier to my "qr" regex so I can use the direct match as in #2 or #3 above?

Thanks...

P.S. - I also just noticed that in addition to stripping out the 'g' option, the 'x' option doesn't seem to work in the regex's parens, i.e. - (?x).