Re^2: Question about MP3::Tag and undef id3v2

Hmm, no, it's commented because there is no id3v2 :

$VAR1 = \undef;
Can't call method "get_frame_ids" on an undefined value at ./test.pl l
+ine 26.
[download]

That's why I do my $id3v2 = exists $mp3->{ID3v2} ? $mp3->{ID3v2} : $mp3->new_tag("ID3v2");

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Re^3: Question about MP3::Tag and undef id3v2 by kcott (Archbishop) on Sep 06, 2017 at 06:12 UTC
G'day DecMoon, Welcome to the Monastery. These are lines `25` and `26` in the code you posted: `print Dumper(\$id3v2); print Dumper(\$id3v2->get_frame_ids);` [download] The first line of output you show (`$VAR1 = \undef;`) is telling you that `$id3v2` is `undef` (i.e. it's undefined). So, "`$id3v2->get_frame_ids`" (in line `26`) is equivalent to "`undef->get_frame_ids`". That's effectively what the second line of output you show is telling you. You'll need to do something with your assignment to `$id3v2`. I'm unfamiliar with the `MP3::Tag` module, so I'm not really in a position to advise you what that "something" might be. Options could include: checking for definedness; setting a default value; skipping some part of the code if it's not defined; or something completely different. — Ken	[reply] [d/l] [select]

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Re^3: Question about MP3::Tag and undef id3v2
by kcott (Archbishop) on Sep 06, 2017 at 06:12 UTC

G'day DecMoon,

Welcome to the Monastery.

These are lines 25 and 26 in the code you posted:

print Dumper(\$id3v2);
print Dumper(\$id3v2->get_frame_ids);
[download]

The first line of output you show ($VAR1 = \undef;) is telling you that $id3v2 is undef (i.e. it's undefined).

So, "$id3v2->get_frame_ids" (in line 26) is equivalent to "undef->get_frame_ids". That's effectively what the second line of output you show is telling you.

You'll need to do something with your assignment to $id3v2. I'm unfamiliar with the MP3::Tag module, so I'm not really in a position to advise you what that "something" might be. Options could include: checking for definedness; setting a default value; skipping some part of the code if it's not defined; or something completely different.

— Ken

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