Printing Protocol

The protocol for delegating how a graphtage.TreeNode or graphtage.Edit is printed in graphtage.GraphtageFormatter.print() is as follows:

1. Determine the actual object to be printed:

   • If node_or_edit is an graphtage.Edit:

     • If with_edits, then choose the edit

     • Otherwise, choose node_or_edit.from_node

   • If node_or_edit is a graphtage.TreeNode:

     • If with_edits and the node is edited and has a non-zero cost,

       then choose node_or_edit.edit:

       node_or_edit.edit is not None and node_or_edit.edit.bounds().lower_bound > 0
       

     • Otherwise choose node_or_edit

2. If the chosen object is an edit:

   • See if there is a specialized formatter for this edit by calling graphtage.formatter.Formatter.get_formatter()

   • If so, delegate to that formatter and return.

   • If not, try calling the edit’s graphtage.Edit.print() method. If NotImplementedError is not raised, return.

3. If the chosen object is a node, or if we failed to find a printer for the edit:

   • See if there is a specialized formatter for this node by calling graphtage.formatter.Formatter.get_formatter()

   • If so, delegate to that formatter and return.

   • If not, print a debug warning and delegate to the node’s internal print implementation graphtage.TreeNode.print().

This is implemented in graphtage.GraphtageFormatter.print(). See the Formatting Protocol for how formatters are chosen.