"Future::Exception" − an exception type for failed Futures
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";
}
}
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.
$e = Future::Exception−>from_future( $f )
Constructs a new "Future::Exception" wrapping the given failed future.
$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.
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.
$f = $e−>as_future
Returns a new "Future" object in a failed state matching the exception.
Paul Evans <[email protected]>