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Future::Exception(3pm) User Contributed Perl Documentation Future::Exception(3pm)

NAME

"Future::Exception" - an exception type for failed Futures

SYNOPSIS

   use Scalar::Util qw( blessed );
   use Syntax::Keyword::Try;
   try {
      my $f = ...;
      my @result = $f->result;
      ...
   }
   catch {
      if( blessed($@) and $@->isa( "Future::Exception" ) {
         print STDERR "The ", $@->category, " failed: ", $@->message, "\n";
      }
   }

DESCRIPTION

The "get" method on a failed Future instance will throw an exception to indicate that the future failed. A failed future can contain a failure category name and other details as well as the failure message, so in this case the exception will be an instance of "Future::Exception" to make these values accessible.

Users should not depend on exact class name matches, but instead rely on inheritence, as a later version of this implementation might dynamically create subclasses whose names are derived from the Future failure category string, to assist with type matching. Note the use of "->isa" in the SYNOPSIS example.

CONSTRUCTOR

from_future

   $e = Future::Exception->from_future( $f )

Constructs a new "Future::Exception" wrapping the given failed future.

ACCESSORS

   $message  = $e->message
   $category = $e->category
   @details  = $e->details

Additionally, the object will stringify to return the message value, for the common use-case of printing, regexp testing, or other behaviours.

METHODS

throw

   Future::Exception->throw( $message, $category, @details )

Since version 0.41.

Constructs a new exception object and throws it using die(). This method will not return, as it raises the exception directly.

If $message does not end in a linefeed then the calling file and line number are appended to it, in the same way die() does.

as_future

   $f = $e->as_future

Returns a new "Future" object in a failed state matching the exception.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

2023-03-18 perl v5.40.0