Re: Dereference a reference to a file handle created with IO::File

Not 100% sure this is your issue but if you use anything in the indirect object / filehandle argument "slot" to print other than a simple scalar variable (edit: or a plain bareword, of course) you're going to need to wrap it in a block like print { $ads{ $this_ad} } "blah blah";. I'm surprised that it's even parsing and not throwing a syntax error the way you've got it now (samples w/5.32.0 on OS X).

$ perl -MO=Deparse,-p,-q -E 'print $ads{$this_ad} "$line\n";'
String found where operator expected at -e line 1, near "} "$line\n""
        (Missing operator before  "$line\n"?)
syntax error at -e line 1, near "} "$line\n""
-e had compilation errors.

$ perl -MO=Deparse,-p,-q -E 'print { $ads{$this_ad} } "$line\n";'
use feature 'current_sub', 'bitwise', 'evalbytes', 'fc', 'postderef_qq
+', 'say', 'state', 'switch', 'unicode_strings', 'unicode_eval';
print({$ads{$this_ad};} ($line . "\n"));
-e syntax OK
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Afterthought: you also could call the print method on your handle as an alternative: $ads{$this_ad}->print( "blah" )

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Re^2: Dereference a reference to a file handle created with IO::File
by dgdriscoll (Initiate) on Oct 28, 2020 at 18:43 UTC

Thank you very much. I chose your second suggestion, calling a method on the handle as being both shorter and, to me at least, clearer. There is something about nested {}'s when the inner and outer set do different things that is challenging for someone who gets into Perl once every couple of years or so. If there is any performance differential, it won't matter in my case. Thanks again, Dave Driscoll

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