def insert_scene_node()

in question_generation/question_engine.py [0:0]

• 30 lines of code
• 9 McCabe index (conditional complexity)

def insert_scene_node(nodes, idx):
  # First make a shallow-ish copy of the input
  new_nodes = []
  for node in nodes:
    new_node = {
      'type': node['type'],
      'inputs': node['inputs'],
    }
    if 'side_inputs' in node:
      new_node['side_inputs'] = node['side_inputs']
    new_nodes.append(new_node)

  # Replace the specified index with a scene node
  new_nodes[idx] = {'type': 'scene', 'inputs': []}

  # Search backwards from the last node to see which nodes are actually used
  output_used = [False] * len(new_nodes)
  idxs_to_check = [len(new_nodes) - 1]
  while idxs_to_check:
    cur_idx = idxs_to_check.pop()
    output_used[cur_idx] = True
    idxs_to_check.extend(new_nodes[cur_idx]['inputs'])

  # Iterate through nodes, keeping only those whose output is used;
  # at the same time build up a mapping from old idxs to new idxs
  old_idx_to_new_idx = {}
  new_nodes_trimmed = []
  for old_idx, node in enumerate(new_nodes):
    if output_used[old_idx]:
      new_idx = len(new_nodes_trimmed)
      new_nodes_trimmed.append(node)
      old_idx_to_new_idx[old_idx] = new_idx

  # Finally go through the list of trimmed nodes and change the inputs
  for node in new_nodes_trimmed:
    new_inputs = []
    for old_idx in node['inputs']:
      new_inputs.append(old_idx_to_new_idx[old_idx])
    node['inputs'] = new_inputs

  return new_nodes_trimmed