spaCy/spacy/tokenizer.pyx

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# cython: embedsignature=True
from __future__ import unicode_literals
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from os import path
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import re
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from cython.operator cimport dereference as deref
from cython.operator cimport preincrement as preinc
from cymem.cymem cimport Pool
from preshed.maps cimport PreshMap
from .structs cimport UniStr
from .strings cimport slice_unicode
from .morphology cimport set_morph_from_dict
from . import util
from .util import read_lang_data
from .tokens import Tokens
cdef class Tokenizer:
def __init__(self, Vocab vocab, rules, prefix_re, suffix_re, infix_re,
pos_tags, tag_names):
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self.mem = Pool()
self._cache = PreshMap()
self._specials = PreshMap()
self._prefix_re = prefix_re
self._suffix_re = suffix_re
self._infix_re = infix_re
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self.vocab = vocab
self._load_special_tokenization(rules, pos_tags, tag_names)
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cpdef Tokens tokens_from_list(self, list strings):
cdef int length = sum([len(s) for s in strings])
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cdef Tokens tokens = Tokens(self.vocab, ' '.join(strings))
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if length == 0:
return tokens
cdef UniStr string_struct
cdef unicode py_string
cdef int idx = 0
for i, py_string in enumerate(strings):
slice_unicode(&string_struct, py_string, 0, len(py_string))
tokens.push_back(idx, <const LexemeC*>self.vocab.get(tokens.mem, &string_struct))
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idx += len(py_string) + 1
return tokens
def __call__(self, unicode string):
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"""Tokenize a string.
The tokenization rules are defined in three places:
* The data/<lang>/tokenization table, which handles special cases like contractions;
* The data/<lang>/prefix file, used to build a regex to split off prefixes;
* The data/<lang>/suffix file, used to build a regex to split off suffixes.
The string is first split on whitespace. To tokenize a whitespace-delimited
chunk, we first try to look it up in the special-cases. If it's not found,
we split off a prefix, and then try again. If it's still not found, we
split off a suffix, and repeat.
Args:
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string (unicode): The string to be tokenized.
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Returns:
tokens (Tokens): A Tokens object, giving access to a sequence of LexemeCs.
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"""
cdef int length = len(string)
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cdef Tokens tokens = Tokens(self.vocab, string)
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if length == 0:
return tokens
cdef int i = 0
cdef int start = 0
cdef bint cache_hit
cdef Py_UNICODE* chars = string
cdef bint in_ws = Py_UNICODE_ISSPACE(chars[0])
cdef UniStr span
for i in range(1, length):
# TODO: Allow control of hyphenation
if (Py_UNICODE_ISSPACE(chars[i]) or chars[i] == '-') != in_ws:
#if Py_UNICODE_ISSPACE(chars[i]) != in_ws:
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if start < i:
slice_unicode(&span, chars, start, i)
cache_hit = self._try_cache(start, span.key, tokens)
if not cache_hit:
self._tokenize(tokens, &span, start, i)
in_ws = not in_ws
start = i
if chars[i] == ' ':
start += 1
i += 1
if start < i:
slice_unicode(&span, chars, start, i)
cache_hit = self._try_cache(start, span.key, tokens)
if not cache_hit:
self._tokenize(tokens, &span, start, i)
return tokens
cdef int _try_cache(self, int idx, hash_t key, Tokens tokens) except -1:
cached = <_Cached*>self._cache.get(key)
if cached == NULL:
return False
cdef int i
if cached.is_lex:
for i in range(cached.length):
idx = tokens.push_back(idx, cached.data.lexemes[i])
else:
for i in range(cached.length):
idx = tokens.push_back(idx, &cached.data.tokens[i])
return True
cdef int _tokenize(self, Tokens tokens, UniStr* span, int start, int end) except -1:
cdef vector[LexemeC*] prefixes
cdef vector[LexemeC*] suffixes
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cdef hash_t orig_key
cdef int orig_size
orig_key = span.key
orig_size = tokens.length
self._split_affixes(span, &prefixes, &suffixes)
self._attach_tokens(tokens, start, span, &prefixes, &suffixes)
self._save_cached(&tokens.data[orig_size], orig_key, tokens.length - orig_size)
cdef UniStr* _split_affixes(self, UniStr* string, vector[const LexemeC*] *prefixes,
vector[const LexemeC*] *suffixes) except NULL:
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cdef size_t i
cdef UniStr prefix
cdef UniStr suffix
cdef UniStr minus_pre
cdef UniStr minus_suf
cdef size_t last_size = 0
while string.n != 0 and string.n != last_size:
last_size = string.n
pre_len = self._find_prefix(string.chars, string.n)
if pre_len != 0:
slice_unicode(&prefix, string.chars, 0, pre_len)
slice_unicode(&minus_pre, string.chars, pre_len, string.n)
# Check whether we've hit a special-case
if minus_pre.n >= 1 and self._specials.get(minus_pre.key) != NULL:
string[0] = minus_pre
prefixes.push_back(self.vocab.get(self.vocab.mem, &prefix))
break
suf_len = self._find_suffix(string.chars, string.n)
if suf_len != 0:
slice_unicode(&suffix, string.chars, string.n - suf_len, string.n)
slice_unicode(&minus_suf, string.chars, 0, string.n - suf_len)
# Check whether we've hit a special-case
if minus_suf.n >= 1 and self._specials.get(minus_suf.key) != NULL:
string[0] = minus_suf
suffixes.push_back(self.vocab.get(self.vocab.mem, &suffix))
break
if pre_len and suf_len and (pre_len + suf_len) <= string.n:
slice_unicode(string, string.chars, pre_len, string.n - suf_len)
prefixes.push_back(self.vocab.get(self.vocab.mem, &prefix))
suffixes.push_back(self.vocab.get(self.vocab.mem, &suffix))
elif pre_len:
string[0] = minus_pre
prefixes.push_back(self.vocab.get(self.vocab.mem, &prefix))
elif suf_len:
string[0] = minus_suf
suffixes.push_back(self.vocab.get(self.vocab.mem, &suffix))
if self._specials.get(string.key):
break
return string
cdef int _attach_tokens(self, Tokens tokens, int idx, UniStr* string,
vector[const LexemeC*] *prefixes,
vector[const LexemeC*] *suffixes) except -1:
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cdef bint cache_hit
cdef int split
cdef const LexemeC* const* lexemes
cdef LexemeC* lexeme
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cdef UniStr span
cdef int i
if prefixes.size():
for i in range(prefixes.size()):
idx = tokens.push_back(idx, prefixes[0][i])
if string.n != 0:
cache_hit = self._try_cache(idx, string.key, tokens)
if cache_hit:
# Get last idx
idx = tokens.data[tokens.length - 1].idx
# Increment by last length
idx += tokens.data[tokens.length - 1].lex.length
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else:
split = self._find_infix(string.chars, string.n)
if split == 0 or split == -1:
idx = tokens.push_back(idx, self.vocab.get(tokens.mem, string))
else:
slice_unicode(&span, string.chars, 0, split)
idx = tokens.push_back(idx, self.vocab.get(tokens.mem, &span))
slice_unicode(&span, string.chars, split, split+1)
idx = tokens.push_back(idx, self.vocab.get(tokens.mem, &span))
slice_unicode(&span, string.chars, split + 1, string.n)
idx = tokens.push_back(idx, self.vocab.get(tokens.mem, &span))
cdef vector[const LexemeC*].reverse_iterator it = suffixes.rbegin()
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while it != suffixes.rend():
idx = tokens.push_back(idx, deref(it))
preinc(it)
cdef int _save_cached(self, const TokenC* tokens, hash_t key, int n) except -1:
cdef int i
for i in range(n):
if tokens[i].lex.id == 1:
return 0
cached = <_Cached*>self.mem.alloc(1, sizeof(_Cached))
cached.length = n
cached.is_lex = True
lexemes = <const LexemeC**>self.mem.alloc(n, sizeof(LexemeC**))
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for i in range(n):
lexemes[i] = tokens[i].lex
cached.data.lexemes = <const LexemeC* const*>lexemes
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self._cache.set(key, cached)
cdef int _find_infix(self, Py_UNICODE* chars, size_t length) except -1:
cdef unicode string = chars[:length]
match = self._infix_re.search(string)
return match.start() if match is not None else 0
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cdef int _find_prefix(self, Py_UNICODE* chars, size_t length) except -1:
cdef unicode string = chars[:length]
match = self._prefix_re.search(string)
return (match.end() - match.start()) if match is not None else 0
cdef int _find_suffix(self, Py_UNICODE* chars, size_t length) except -1:
cdef unicode string = chars[:length]
match = self._suffix_re.search(string)
return (match.end() - match.start()) if match is not None else 0
def _load_special_tokenization(self, object rules, object tag_map, object tag_names):
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'''Add a special-case tokenization rule.
'''
cdef int i
cdef unicode chunk
cdef list substrings
cdef unicode form
cdef unicode lemma
cdef dict props
cdef LexemeC** lexemes
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cdef hash_t hashed
cdef UniStr string
for chunk, substrings in sorted(rules.items()):
tokens = <TokenC*>self.mem.alloc(len(substrings) + 1, sizeof(TokenC))
for i, props in enumerate(substrings):
form = props['F']
lemma = props.get("L", None)
slice_unicode(&string, form, 0, len(form))
tokens[i].lex = <LexemeC*>self.vocab.get(self.vocab.mem, &string)
if lemma is not None:
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tokens[i].lemma = self.vocab.strings[lemma]
else:
tokens[i].lemma = 0
if 'pos' in props:
# TODO: Clean up this mess...
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tokens[i].tag = self.vocab.strings[props['pos']]
tokens[i].pos = tag_map[props['pos']][0]
# These are defaults, which can be over-ridden by the
# token-specific props.
set_morph_from_dict(&tokens[i].morph, tag_map[props['pos']][1])
if tokens[i].lemma == 0:
tokens[i].lemma = tokens[i].lex.orth
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set_morph_from_dict(&tokens[i].morph, props)
cached = <_Cached*>self.mem.alloc(1, sizeof(_Cached))
cached.length = len(substrings)
cached.is_lex = False
cached.data.tokens = tokens
slice_unicode(&string, chunk, 0, len(chunk))
self._specials.set(string.key, cached)
self._cache.set(string.key, cached)