in reply to Perl try { } catch(e) { }

Have you looked at how Try::Tiny does its thing. Most likely, you can reuse that code for your implementation.

Note that catch(e) is invalid syntax in Perl (unless you declare a parameterless function e()). Resorting to something like catch  my $e { is not allowed by Perl syntax either, because the & prototype works its syntactical magic only when it is the first prototype character.

You could use something like

catch { my $e= $@;
    ...
}

[download]

... if you really want to rename $@.

Replies are listed 'Best First'.
Re^2: Perl try { } catch(e) { }
by Superfox il Volpone (Sexton) on Mar 03, 2015 at 15:18 UTC
    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
[reply]
[d/l]

      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]
      "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

      «The Crux of the Biscuit is the Apostrophe»

[reply]
[d/l]
        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]

        See also

        «The Crux of the Biscuit is the Apostrophe»

[reply]

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