Role::HasMessage::Errf - a thing with a String::Errf-powered message


version 0.007


In your class...

  package Errfy;
  use Moose;

  with 'Role::HasMessage::Errf';

  has payload => (
    is  => 'ro',
    isa => 'HashRef',
    required => 1,


  my $thing = Errfy->new({
    message => "%{error_count;error}n encountered at %{when}t",
    payload => {
      error_count => 2,
      when        => time,

  # prints: 2 errors encountered at 2010-10-20 19:23:42
  print $thing->message;


Role::HasMessage::Errf is an implementation of Role::HasMessage that uses String::Errf to format sprintf-like message strings. It adds a message_fmt attribute, initialized by the message argument. The value should be a String::Errf format string.

When the provided message method is called, it will fill in the format string with the hashref returned by calling the payload method, which must be implemented by the including class.

Role::HasMessage::Errf is a parameterized role. The default parameter lets you set a default format string or callback. The lazy parameter sets whether or not the message_fmt attribute is lazy. Setting it lazy will require that a default is provided.


This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.


Ricardo Signes <>


This software is copyright (c) 2022 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.