"""Block Deproj for deprojectivization of pseudo-projective trees à la Nivre & Nilsson (2005).

See ud.transform.Proj for details.

TODO: implement also path and head+path strategies.

"""

from udapi.core.block import Block

class Deproj(Block):

"""De-projectivize the trees à la Nivre & Nilsson (2005)."""

def __init__(self, strategy='head', label='misc', **kwargs):

"""Create the Deproj block object."""

super().__init__(**kwargs)

self.strategy = strategy

self.label = label

def process_node(self, node):

if self.label == 'misc':

label = node.misc['pproj']

elif self.label == 'deprel':

parts = node.sdeprel.split('+', 1)

if len(parts) == 2:

label = parts[1]

node.deprel = node.udeprel + (':' + parts[0] if parts[0] else '')

else:

label = ''

else:

raise(ValueError('Unknown parameter label=%s' % self.label))

if label == '':

return

reconstructed_parent = self.head_strategy(node, label)

if reconstructed_parent:

node.parent = reconstructed_parent

def head_strategy(self, node, label):

queue = [n for n in node.parent.children if n != node] # TODO deque

while queue:

adept = queue.pop(0)

if adept.udeprel == label:

return adept

queue.extend(adept.children)

return None