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List:       perl5-porters
Subject:    Re: [PATCH] Re: [PATCH] File::Copy & permission bits.
From:       Charles Bailey <bailey.charles () gmail ! com>
Date:       2009-01-29 3:24:43
Message-ID: b78749dd0901281924j6d02883ctcd6194abb9b893be () mail ! gmail ! com
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On Mon, Jan 26, 2009 at 4:51 AM, Aristotle Pagaltzis <pagaltzis@gmx.de> wrote:
> * Charles Bailey <bailey.charles@gmail.com> [2009-01-25 05:15]:
>> - Remove Scalar::Util. It looks possible to replace the
>>   blessed() and overload() checks with something like
>>     my $ra = ref $a;  "$a" !~ /^$ra\(0x[0-9a-f]+\)$/
>>   but I need to think it through a bit more and test it.
>
> `blessed` can be written `UNIVERSAL::can( $var, 'can' )`.

Sure, but we may not need to look at blessedness directly to figure
out what we need here: whether we need to let an object stringify
itself into something useful.  I think the "internal" option below
will do the trick, letting us avoid loading overload.pm as well.

-- 
Regards,
Charles Bailey
Lists: bailey _dot_ charles _at_ gmail _dot_ com
Other: bailey _at_ newman _dot_ upenn _dot_ edu

#!/usr/local/bin/perl

use IO::File;
use IO::Scalar;
use Path::Class;

use Scalar::Util 'blessed';
use overload;

my $str = '/some/where/out/there';
my $sref = \$str;
my $iosc = IO::Scalar->new(\$str);
my $pc = dir(split /\//, $str);
my $fh = IO::File->new($0);
my $gr = \do { local *GLOB; };
open FH, $0;

sub with_modules {
  Scalar::Util::blessed($_[0]) &&
  overload::Method($_[0],q{""})
  ? 'stringified' : 'native';
}

sub internal {
  ref($_[0]) &&
    "$_[0]" !~ /^(?:[\w:]+=)?\w+\(0x[0-9a-f]+\)/
     ? 'stringified' : 'native';
}

for my $c ( [ 'Flat string', $str ],
	    [ 'Old-style file handle', FH ],
	    [ 'Scalar ref',  $sref ],
	    [ 'Glob', $gr ],
	    [ 'IO::Scalar',  $iosc ],
	    [ 'Path::Class', $pc ],
	    [ 'IO::File', $fh ],) {
  my $mod = with_modules($c->[1]);
  my $int = internal($c->[1]);
  print "$c->[0] ($c->[1]): modules=$mod internal=$int ",
        ($mod eq $int ? 'consistent' : 'INCONSISTENT'),
	"\n";
}
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