NAME

Class::Workflow::Util::Delta - calculate deltas between workflow instances

SYNOPSIS

my $next = $transition->apply( $i );

my $d = Class::Workflow::Util::Delta->new(
	from => $i,
	to   => $next,
);

foreach my $field ( keys %{ $d->changes } ) {
	my $change = $d->changes->{$field};
	print "$field changed from $change->{from} to $change->{to}\n";
}

DESCRIPTION

Usually you need to calculate deltas between workflow instances in order to normalize the database of history changes so that there are no duplicate fields.

This module lets you create an object that represents the change between any two instances (not necessarily related), allowing you to represent a history step.

See Class::Workflow::YAML