def induce(parsed_sents):
def get_rule_from_node(node):
if not node.is_leaf():
child_tags = []
for child in node.children:
if child.is_leaf():
leafs[node.tag].add(child.text)
else:
child_tags.append(child.tag)
if len(child_tags):
key = slugify(child_tags)
nodes[node.tag].add(key)
g = Grammar()
for parsed_sent in parsed_sents:
root = Node()
current = root
for char in str(parsed_sent):
if char == '(':
child = Node()
child.parent = current
current.children.append(child)
current = child
elif char == ')':
if isinstance(current, Leaf):
current = current.parent
current = current.parent
elif re.match(r'\s', char):
current.tag_parsed = True
else:
if isinstance(current, Leaf):
current.text += char
elif current.tag_parsed:
leaf = Leaf()
leaf.parent = current
leaf.text += char
current.children.append(leaf)
current = leaf
else:
current.tag += char
leafs = defaultdict(set)
nodes = defaultdict(set)
root.children[0].descend(get_rule_from_node)
for (src, tar_set) in nodes.items():
for slugged_tars in tar_set:
tars = deslugify(slugged_tars)
g.add_rule(src, tars, False)
for (src, tars) in leafs.items():
g.add_rule(src, tars, True)
g.dedup()
return g
