Name

Unexpected - Localised exception classes composed from roles

Synopsis

package YourApp::Exception;

use Moo;

extends 'Unexpected';
with    'Unexpected::TraitFor::ErrorLeader';

__PACKAGE__->ignore_class( 'YourApp::IgnoreMe' );

has '+class' => default => __PACKAGE__;

package YourApp;

use YourApp::Exception;
use Try::Tiny;

sub some_method {
   my $self = shift;

   try   { this_will_fail }
   catch { YourApp::Exception->throw $_ };
}

# OR

sub some_method {
   my $self = shift;

   eval { this_will_fail };
   YourApp::Exception->throw_on_error;
}

# THEN
try   { $self->some_method() }
catch { warn $_->message };

Description

An exception class that supports error messages with placeholders, a throw method with automatic re-throw upon detection of self, conditional throw if an exception was caught and a simplified stack trace in addition to the error message with full stack trace

Configuration and Environment

Applies exception roles to the exception base class Unexpected. See "Dependencies" for the list of roles that are applied

The list of signatures recognised by the constructor method is implemented by the signature parser

Error objects are overloaded to stringify to the full error message plus a leader if the optional Unexpected::TraitFor::ErrorLeader role has been applied

Subroutines/Methods

BUILD

Empty subroutine which is modified by the applied roles

BUILDARGS

Differentiates different constructor method signatures

Diagnostics

String overload is performed in this class as opposed to the stringify error role since overloading is not supported in Moo::Role

Dependencies

• namespace::autoclean
• overload
• Moo
• Unexpected::TraitFor::ExceptionClasses
• Unexpected::TraitFor::StringifyingError
• Unexpected::TraitFor::Throwing
• Unexpected::TraitFor::TracingStacks

Incompatibilities

There are no known incompatibilities in this module

Bugs and Limitations

Throwable did not let me use the stack trace filter directly, it's wrapped inside an attribute constructor. There was nothing else in Throwable that would not have been overridden

There are no known bugs in this module. Please report problems to http://rt.cpan.org/NoAuth/Bugs.html?Dist=Unexpected. Patches are welcome

Acknowledgements

Larry Wall - For the Perl programming language

Throwable::Error - Lifted the stack frame filter from here

John Sargent - Came up with the package name

Author

Peter Flanigan, <pjfl@cpan.org>

License and Copyright

Copyright (c) 2021 Peter Flanigan. All rights reserved

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic

This program is distributed in the hope that it will be useful, but WITHOUT WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE