def _element_2_syntactic_node(cls, element):
cat = element.attrib["cat"]
if element.tag == "lf":
terminal_node = SyntacticNode(cat,
pos=element.attrib["pos"],
lemma=element.attrib["lemma"],
word=element.attrib["word"])
return terminal_node
else:
node = SyntacticNode(cat)
for child_element in element:
child_node = cls._element_2_syntactic_node(child_element)
node.add_child(child_node)
return node
def read_tree(cls, string):
"""Read a SyntacticTree from a string
Args:
string: the input string
For a PSG tree, the format of the tree is similar to a Penn Treebank
tree, without newline characters:
e.g. (S (NP (NNP Mary)) (VP (VBZ loves) (NP (NNP John))))
Returns:
the SyntacticTree represented by the input string
"""
# first, remove the brackets ()
string = string.strip()
if len(string) == 0:
raise ValueError("empty string cannot be a Synstactic Tree")
if string[0] == "(" and string[-1] == ")":
string = string[1:-1]
# split the string with blank character
# if the string has exactly or fewer than one element, it cannot be a
# tree
# if it has two elements, it must be a tree with a terminal node as the
# root
# if it has more than two elements, take the first element as the root
# and other elements as the branches
elements = string.split()
if len(elements) <= 1 or elements[1] == "":
raise ValueError("%s cannot be a tree or subtree" %string)
else:
if len(elements) == 2:
# TODO: if the label comes from CCG parser, turn [] into ()
root = cls._read_terminal_node(elements)
else:
branch_string = " ".join(elements[1:])
root = SyntacticNode(elements[0])
branches = cls._read_branches(branch_string)
for branch in branches:
root.add_child(branch._root)
return SyntacticTree(root)
class EnglishPluralizationSimple(LearningSimulation):
# Lexical
DOG_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'DOG', 1000, 'dog')
TABLE_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'TABLE', 1001, 'teibl')
TREE_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'TREE', 1010, 'tri')
CAR_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'CAR', 1011, 'car')
DEER_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'DEER', 1100, 'dir')
FISH_NODE = SyntacticNode(SyntacticNode.TYPE_ROOT, 'FISH', 1101, 'fish')
# Functional
PLURAL_NODE = SyntacticNode(SyntacticNode.TYPE_FEATURE, '+PL', 1100)
NODES = [
DOG_NODE, TABLE_NODE, TREE_NODE, CAR_NODE, DEER_NODE, FISH_NODE,
PLURAL_NODE
]
VOCABULARY = ['z']
RULES = [
Rule([PLURAL_NODE], 'z', []),
Rule([PLURAL_NODE], '', [DEER_NODE, FISH_NODE])
]
TARGET_GRAMMAR = Grammar(NODES, VOCABULARY, RULES)
DATA = [
Datum(DOG_NODE, [], 'dog'),
Datum(DOG_NODE, [PLURAL_NODE], 'dogz'),
Datum(TABLE_NODE, [], 'teibl'),
Datum(TABLE_NODE, [PLURAL_NODE], 'teiblz'),
Datum(TREE_NODE, [], 'tri'),
Datum(TREE_NODE, [PLURAL_NODE], 'triz'),
Datum(CAR_NODE, [], 'car'),
Datum(CAR_NODE, [PLURAL_NODE], 'carz'),
Datum(DEER_NODE, [], 'dir'),
Datum(DEER_NODE, [PLURAL_NODE], 'dir'),
Datum(FISH_NODE, [], 'fish'),
Datum(FISH_NODE, [PLURAL_NODE], 'fish'),
]
def __init__(self):
super().__init__(self.NODES, self.VOCABULARY, self.RULES, self.DATA)
