Re: Using pack/unpack on a PNG file

[AnomalousMonk]

my $ifh = open("<:raw", "./file-bar.png");

Wishful, also quite surprising that Perl seems happy with it even with warnings and strictures enabled. In any event, the "successful" result (1) of open-ing the file is assigned to  $ifh and this is packed and written (apparently also "successfully") to another file. But it's still junk.

c:\@Work\Perl\monks\sierpinski>perl -wMstrict -MData::Dump -le
"my $ifh = open('<:raw', 'junk.txt');
 dd $ifh;
"
1

Can anyone explain to me how this works — with strictures enabled?

[choroba]

Documented behaviour:

(...) if FILEHANDLE is an expression, its value is the real filehandle. (This is considered a symbolic reference, so use strict "refs" should not be in effect.)

system 'echo abc > 1.txt';
open '<:raw', '1.txt' or die $!;
print while readline '<:raw';
unlink '1.txt';

Update: I wouldn't recomend it, though, as it's confusing to a reader :-) The file is still opened with default layers:

print PerlIO::get_layers("<:raw");
# unixperlio

[AnomalousMonk]

This is considered a symbolic reference, so use strict "refs" should not be in effect.

Yes, but if strictures are enabled the example still runs (and strictures were also enabled above), so I'm still confused:

c:\@Work\Perl\monks\sierpinski>perl -wMstrict -le
"system 'echo abc > 1.txt';
 open '<:raw', '1.txt' or die $!;
 print while readline '<:raw';
"
abc

Update: I wouldn't recomend it, though, as it's confusing to a reader ... Darn right!

[choroba]

We aren't trying to explicitly dereference the symbolic reference.

[Anonymous Monk]

do the open docs lie or tell the truth? needs new bug report

Bug #119547 for perl5: 42->{42} works in strict mode, Bug #3629 for perl5: strict doesn't complain when sort quotes bareword argument,

its not tested

untested here http://perl5.git.perl.org/perl.git/blob/HEAD:/t/lib/strict/refs

untested here http://perl5.git.perl.org/perl.git/blob/HEAD:/t/io/open.t
{perl #91416} Deparse open("blah blah blah") properly
http://perl5.git.perl.org/perl.git/commit/204263bc1eb63f1dfd6180c05dca8cec2c319504
perldelta for deparsing open("string")
Bug #91416 for perl5: Deparses produces invalid barewords