my $chain = Graph::Easy::Layout::Chain->new( start => $node );
Create a new chain and set its starting node to $node.
my $len = $chain->length();
Return the length of the chain, in nodes.
my $len = $chain->length( $node );
Given an optional $node as argument, returns the length
from that node onwards. For the chain with the three nodes
A, B and C would return 3, 2, and 1 for A, B and C, respectively.
Returns 0 if the passed node is not part of this chain.
my @nodes = $chain->nodes();
Return all the node objects in the chain as list, in order.
$chain->add_node( $node );
Add $node to the end of the chain.
my $node = $chain->start();
Return first node in the chain.
my $node = $chain->end();
Return last node in the chain.
my $todo = $chain->layout();
Return an action stack as array ref, containing the nec. actions to
layout the chain (nodes, plus interlinks in the chain).
Will recursively traverse all chains linked to this chain.
my $chain->merge ( $other_chain );
my $chain->merge ( $other_chain, $where );
Merge the other chain into ourselves, adding its nodes at our end.
The other chain is emptied and must be deleted by the caller.
If $where is defined and a member of $other_chain, absorb only the
nodes from $where onwards, instead of all of them.
$last_error = $node->error();
$node->error($error); # set new messags
$node->error(); # clear error
Returns the last error message, or for no error.
Dump the chain to STDERR, to aid debugging.