File size: 9,212 Bytes
19b8775 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 |
"""
Reads ParseTree objects from a file, string, or similar input
Works by first splitting the input into (, ), and all other tokens,
then recursively processing those tokens into trees.
"""
from collections import deque
import logging
import os
import re
from stanza.models.constituency.parse_tree import Tree
from stanza.utils.get_tqdm import get_tqdm
tqdm = get_tqdm()
OPEN_PAREN = "("
CLOSE_PAREN = ")"
logger = logging.getLogger('stanza.constituency')
# A few specific exception types to clarify parsing errors
# They store the line number where the error occurred
class UnclosedTreeError(ValueError):
"""
A tree looked like (Foo
"""
def __init__(self, line_num):
super().__init__("Found an unfinished tree (missing close brackets). Tree started on line %d" % line_num)
self.line_num = line_num
class ExtraCloseTreeError(ValueError):
"""
A tree looked like (Foo))
"""
def __init__(self, line_num):
super().__init__("Found a broken tree (extra close brackets). Tree started on line %d" % line_num)
self.line_num = line_num
class UnlabeledTreeError(ValueError):
"""
A tree had no label, such as ((Foo) (Bar))
This does not actually happen at the root, btw, as ROOT is silently added
"""
def __init__(self, line_num):
super().__init__("Found a tree with no label on a node! Line number %d" % line_num)
self.line_num = line_num
class MixedTreeError(ValueError):
"""
Leaf and constituent children are mixed in the same node
"""
def __init__(self, line_num, child_label, children):
super().__init__("Found a tree with both text children and bracketed children! Line number {} Child label {} Children {}".format(line_num, child_label, children))
self.line_num = line_num
self.child_label = child_label
self.children = children
def normalize(text):
return text.replace("-LRB-", "(").replace("-RRB-", ")")
def read_single_tree(token_iterator, broken_ok):
"""
Build a tree from the tokens in the token_iterator
"""
# we were called here at a open paren, so start the stack of
# children with one empty list already on it
children_stack = deque()
children_stack.append([])
text_stack = deque()
text_stack.append([])
token = next(token_iterator, None)
token_iterator.set_mark()
while token is not None:
if token == OPEN_PAREN:
children_stack.append([])
text_stack.append([])
elif token == CLOSE_PAREN:
text = text_stack.pop()
children = children_stack.pop()
if text:
pieces = " ".join(text).split()
if len(pieces) == 1:
child = Tree(pieces[0], children)
else:
# the assumption here is that a language such as VI may
# have spaces in the words, but it still represents
# just one child
label = pieces[0]
child_label = " ".join(pieces[1:])
if children:
if broken_ok:
child = Tree(label, children + [Tree(normalize(child_label))])
else:
raise MixedTreeError(token_iterator.line_num, child_label, children)
else:
child = Tree(label, Tree(normalize(child_label)))
if not children_stack:
return child
else:
if not children_stack:
return Tree("ROOT", children)
elif broken_ok:
child = Tree(None, children)
else:
raise UnlabeledTreeError(token_iterator.line_num)
children_stack[-1].append(child)
else:
text_stack[-1].append(token)
token = next(token_iterator, None)
raise UnclosedTreeError(token_iterator.get_mark())
LINE_SPLIT_RE = re.compile(r"([()])")
class TokenIterator:
"""
A specific iterator for reading trees from a tree file
The idea is that this will keep track of which line
we are processing, so that an error can be logged
from the correct line
"""
def __init__(self):
self.token_iterator = iter([])
self.line_num = -1
self.mark = None
def set_mark(self):
"""
The mark is used for determining where the start of a tree occurs for an error
"""
self.mark = self.line_num
def get_mark(self):
if self.mark is None:
raise ValueError("No mark set!")
return self.mark
def __iter__(self):
return self
def __next__(self):
n = next(self.token_iterator, None)
while n is None:
self.line_num = self.line_num + 1
line = next(self.line_iterator)
if line is None:
raise StopIteration
line = line.strip()
if not line:
continue
pieces = LINE_SPLIT_RE.split(line)
pieces = [x.strip() for x in pieces]
pieces = [x for x in pieces if x]
self.token_iterator = iter(pieces)
n = next(self.token_iterator, None)
return n
class TextTokenIterator(TokenIterator):
def __init__(self, text, use_tqdm=True):
super().__init__()
self.lines = text.split("\n")
self.num_lines = len(self.lines)
if self.num_lines > 1000 and use_tqdm:
self.line_iterator = iter(tqdm(self.lines))
else:
self.line_iterator = iter(self.lines)
class FileTokenIterator(TokenIterator):
def __init__(self, filename):
super().__init__()
self.filename = filename
def __enter__(self):
# TODO: use the file_size instead of counting the lines
# file_size = Path(self.filename).stat().st_size
with open(self.filename) as fin:
num_lines = sum(1 for _ in fin)
self.file_obj = open(self.filename)
if num_lines > 1000:
self.line_iterator = iter(tqdm(self.file_obj, total=num_lines))
else:
self.line_iterator = iter(self.file_obj)
return self
def __exit__(self, exc_type, exc_value, exc_tb):
if self.file_obj:
self.file_obj.close()
def read_token_iterator(token_iterator, broken_ok, tree_callback):
trees = []
token = next(token_iterator, None)
while token:
if token == OPEN_PAREN:
next_tree = read_single_tree(token_iterator, broken_ok=broken_ok)
if next_tree is None:
raise ValueError("Tree reader somehow created a None tree! Line number %d" % token_iterator.line_num)
if tree_callback is not None:
transformed = tree_callback(next_tree)
if transformed is not None:
trees.append(transformed)
else:
trees.append(next_tree)
token = next(token_iterator, None)
elif token == CLOSE_PAREN:
raise ExtraCloseTreeError(token_iterator.line_num)
else:
raise ValueError("Tree document had text between trees! Line number %d" % token_iterator.line_num)
return trees
def read_trees(text, broken_ok=False, tree_callback=None, use_tqdm=True):
"""
Reads multiple trees from the text
TODO: some of the error cases we hit can be recovered from
"""
token_iterator = TextTokenIterator(text, use_tqdm)
return read_token_iterator(token_iterator, broken_ok=broken_ok, tree_callback=tree_callback)
def read_tree_file(filename, broken_ok=False, tree_callback=None):
"""
Read all of the trees in the given file
"""
with FileTokenIterator(filename) as token_iterator:
trees = read_token_iterator(token_iterator, broken_ok=broken_ok, tree_callback=tree_callback)
return trees
def read_directory(dirname, broken_ok=False, tree_callback=None):
"""
Read all of the trees in all of the files in a directory
"""
trees = []
for filename in sorted(os.listdir(dirname)):
full_name = os.path.join(dirname, filename)
trees.extend(read_tree_file(full_name, broken_ok, tree_callback))
return trees
def read_treebank(filename, tree_callback=None):
"""
Read a treebank and alter the trees to be a simpler format for learning to parse
"""
logger.info("Reading trees from %s", filename)
trees = read_tree_file(filename, tree_callback=tree_callback)
trees = [t.prune_none().simplify_labels() for t in trees]
illegal_trees = [t for t in trees if len(t.children) > 1]
if len(illegal_trees) > 0:
raise ValueError("Found {} tree(s) which had non-unary transitions at the ROOT. First illegal tree: {:P}".format(len(illegal_trees), illegal_trees[0]))
return trees
def main():
"""
Reads a sample tree
"""
text="( (SBARQ (WHNP (WP Who)) (SQ (VP (VBZ sits) (PP (IN in) (NP (DT this) (NN seat))))) (. ?)))"
trees = read_trees(text)
print(trees)
if __name__ == '__main__':
main()
|