Re^2: Perl try { } catch(e) { }

Aaaaahh I think I understood now how this is supposed to work:

#!/usr/bin/env perl


sub try(&$) {
  my ($try, $catch) = @_;
  
  eval { # perl try
    &$try
  }; if($@){ # perl catch
    &$catch($@);
  }
}
sub catch(&){ shift }

try{
  die("Frankie");
} catch {
  my $e = shift;
  print("Hello world $e\n");
}
[download]

catch { ... } is invoked before the block in the try { ...}, and all it does is to return the block as a reference to the anonymous function defined by the catch block.
Tricky mechanism.

Thanks,
s.fox

Comment on Re^2: Perl try { } catch(e) { } Download Code

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Re^3: Perl try { } catch(e) { } by Anonymous Monk on Mar 03, 2015 at 15:29 UTC
If you're going to use that code instead of Try::Tiny (which by the way is pure Perl and has no non-core dependencies), make sure you read the "Background" section of Try::Tiny's docs, as there are a number of issues with $@!	[reply]
Re^3: Perl try { } catch(e) { } by karlgoethebier (Abbot) on Mar 03, 2015 at 17:39 UTC
"Aaaaahh I think I understood ..." I don't (for the moment) - but i don't care about and just do: `#!/usr/bin/env perl use strict; use warnings; use Try::Tiny; try { die qq(Goodbye World!); } catch { warn $_; }; __END__` [download] Best regards, Karl ŤThe Crux of the Biscuit is the Apostropheť	[reply] [d/l]
Re^4: Perl try { } catch(e) { } by jdeguest (Beadle) on Mar 24, 2021 at 03:29 UTC
There is a full implementation of try-catch block using perl filters: Nice::Try So you can do something like embedded try-catch block, return, variable assignments, catching class exception, etc. There is no need for semicolon on the lack brace. `use Nice::Try; try { # do something die( "Argh...\n" ); } catch( $wow ) { return( $self->error( "Caught an error: $wow" ) ); } finally { # do some cleanup }` [download] Full disclosure: I am the author of this module that I created when Devel::Declare on which TryCatch was relying became obsolete.	[reply] [d/l]
Re^5: Perl try { } catch(e) { } by haukex (Archbishop) on Mar 24, 2021 at 08:51 UTC
There is a full implementation of try-catch block using perl filters Source filters are unfortunately quite dangerous, they are very prone to making code extremely brittle (Update: for example, Switch was removed from the Perl core for that reason, see e.g. Perl Code Changes Behavior if Two Subroutine definitions are swapped). Note that there is currently development underway to add try/catch to Perl natively - see Adding a try/catch syntax to Perl and Progress on try/catch.	[reply]
Re^6: Perl try { } catch(e) { } by jdeguest (Beadle) on Jun 17, 2021 at 02:47 UTC
Re^7: Perl try { } catch(e) { } by haukex (Archbishop) on Jun 17, 2021 at 08:57 UTC
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Re^7: Perl try { } catch(e) { } by Haarg (Priest) on Jun 18, 2021 at 04:10 UTC
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Re^4: Perl try { } catch(e) { } by karlgoethebier (Abbot) on Mar 24, 2021 at 21:44 UTC
See also ŤThe Crux of the Biscuit is the Apostropheť	[reply]