spaCy/spacy/lang.pyx

283 lines
11 KiB
Cython

# cython: profile=True
# cython: embedsignature=True
"""Common classes and utilities across languages.
Provides the main implementation for the spacy tokenizer. Specific languages
subclass the Language class, over-writing the tokenization rules as necessary.
Special-case tokenization rules are read from data/<lang>/tokenization .
"""
from __future__ import unicode_literals
import json
import random
from os import path
import re
from cymem.cymem cimport Pool
from cython.operator cimport preincrement as preinc
from cython.operator cimport dereference as deref
from murmurhash.mrmr cimport hash64
from preshed.maps cimport PreshMap
from .lexeme cimport Lexeme
from .lexeme cimport from_dict as lexeme_from_dict
from .lexeme cimport from_string as lexeme_from_string
from . import orth
from . import util
from .util import read_lang_data
from .tokens import Tokens
cdef class Language:
"""Base class for language-specific tokenizers.
The language's name is used to look up default data-files, found in data/<name.
"""
def __init__(self, name, user_string_features, user_flag_features):
self.name = name
self._mem = Pool()
self.cache = PreshMap(2 ** 25)
self.specials = PreshMap(2 ** 16)
rules, prefix, suffix, infix, lexemes = util.read_lang_data(name)
self.prefix_re = re.compile(prefix)
self.suffix_re = re.compile(suffix)
self.infix_re = re.compile(infix)
self.lexicon = Lexicon(lexemes)
self._load_special_tokenization(rules)
cpdef Tokens tokenize(self, unicode string):
"""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.
Args:
string (unicode): The string to be tokenized.
Returns:
tokens (Tokens): A Tokens object, giving access to a sequence of Lexemes.
"""
cdef int length = len(string)
cdef Tokens tokens = Tokens(self.lexicon.strings, length)
if length == 0:
return tokens
cdef int i = 0
cdef int start = 0
cdef Py_UNICODE* chars = string
cdef bint in_ws = Py_UNICODE_ISSPACE(chars[0])
cdef String span
for i in range(1, length):
if Py_UNICODE_ISSPACE(chars[i]) != in_ws:
if start < i:
string_slice(&span, chars, start, i)
lexemes = <Lexeme**>self.cache.get(span.key)
if lexemes != NULL:
tokens.extend(start, lexemes, 0)
else:
self._tokenize(tokens, &span, start, i)
in_ws = not in_ws
start = i
if chars[i] == ' ':
start += 1
i += 1
if start < i:
string_slice(&span, chars, start, i)
lexemes = <Lexeme**>self.cache.get(span.key)
if lexemes != NULL:
tokens.extend(start, lexemes, 0)
else:
self._tokenize(tokens, &span, start, i)
return tokens
cdef int _tokenize(self, Tokens tokens, String* span, int start, int end) except -1:
cdef vector[Lexeme*] prefixes
cdef vector[Lexeme*] suffixes
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.lex[orig_size], orig_key, tokens.length - orig_size)
cdef String* _split_affixes(self, String* string, vector[Lexeme*] *prefixes,
vector[Lexeme*] *suffixes) except NULL:
cdef size_t i
cdef String prefix
cdef String suffix
cdef String minus_pre
cdef String 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:
string_slice(&prefix, string.chars, 0, pre_len)
string_slice(&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.lexicon.get(&prefix))
break
suf_len = self._find_suffix(string.chars, string.n)
if suf_len != 0:
string_slice(&suffix, string.chars, string.n - suf_len, string.n)
string_slice(&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.lexicon.get(&suffix))
break
if pre_len and suf_len and (pre_len + suf_len) <= string.n:
string_slice(string, string.chars, pre_len, string.n - suf_len)
prefixes.push_back(self.lexicon.get(&prefix))
suffixes.push_back(self.lexicon.get(&suffix))
elif pre_len:
string[0] = minus_pre
prefixes.push_back(self.lexicon.get(&prefix))
elif suf_len:
string[0] = minus_suf
suffixes.push_back(self.lexicon.get(&suffix))
if self.specials.get(string.key):
break
return string
cdef int _attach_tokens(self, Tokens tokens,
int idx, String* string,
vector[Lexeme*] *prefixes,
vector[Lexeme*] *suffixes) except -1:
cdef int split
cdef Lexeme** lexemes
cdef Lexeme* lexeme
cdef String span
if prefixes.size():
idx = tokens.extend(idx, prefixes.data(), prefixes.size())
if string.n != 0:
lexemes = <Lexeme**>self.cache.get(string.key)
if lexemes != NULL:
idx = tokens.extend(idx, lexemes, 0)
else:
split = self._find_infix(string.chars, string.n)
if split == 0 or split == -1:
idx = tokens.push_back(idx, self.lexicon.get(string))
else:
string_slice(&span, string.chars, 0, split)
idx = tokens.push_back(idx, self.lexicon.get(&span))
string_slice(&span, string.chars, split, split+1)
idx = tokens.push_back(idx, self.lexicon.get(&span))
string_slice(&span, string.chars, split + 1, string.n)
idx = tokens.push_back(idx, self.lexicon.get(&span))
cdef vector[Lexeme*].reverse_iterator it = suffixes.rbegin()
while it != suffixes.rend():
idx = tokens.push_back(idx, deref(it))
preinc(it)
cdef int _save_cached(self, Lexeme** tokens, hash_t key, int n) except -1:
lexemes = <Lexeme**>self._mem.alloc(n + 1, sizeof(Lexeme**))
cdef int i
for i in range(n):
lexemes[i] = tokens[i]
lexemes[i + 1] = NULL
self.cache.set(key, lexemes)
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
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, token_rules):
'''Load special-case tokenization rules.
Loads special-case tokenization rules into the Language.cache cache,
read from data/<lang>/tokenization . The special cases are loaded before
any language data is tokenized, giving these priority. For instance,
the English tokenization rules map "ain't" to ["are", "not"].
Args:
token_rules (list): A list of (chunk, tokens) pairs, where chunk is
a string and tokens is a list of strings.
'''
cdef Lexeme** lexemes
cdef hash_t hashed
cdef String string
for uni_string, substrings in token_rules:
lexemes = <Lexeme**>self._mem.alloc(len(substrings) + 1, sizeof(Lexeme*))
for i, substring in enumerate(substrings):
string_from_unicode(&string, substring)
lexemes[i] = <Lexeme*>self.lexicon.get(&string)
lexemes[i + 1] = NULL
string_from_unicode(&string, uni_string)
self.specials.set(string.key, lexemes)
self.cache.set(string.key, lexemes)
cdef class Lexicon:
def __init__(self, lexemes):
self.mem = Pool()
self._dict = PreshMap(2 ** 20)
self.strings = StringStore()
self.size = 0
cdef String string
cdef Lexeme* lexeme
#for py_string, lexeme_dict in lexemes.iteritems():
# string_from_unicode(&string, py_string)
# lexeme = <Lexeme*>self.mem.alloc(1, sizeof(Lexeme))
# lexeme_from_dict(lexeme, lexeme_dict, self.strings)
# self._dict.set(string.key, lexeme)
# self.lexemes.push_back(lexeme)
# self.size += 1
cdef Lexeme* get(self, String* string) except NULL:
cdef Lexeme* lex
lex = <Lexeme*>self._dict.get(string.key)
if lex != NULL:
return lex
lex = <Lexeme*>self.mem.alloc(1, sizeof(Lexeme))
lexeme_from_string(lex, string.chars[:string.n], self.strings)
self._dict.set(string.key, lex)
self.lexemes.push_back(lex)
self.size += 1
return lex
cpdef Lexeme lookup(self, unicode uni_string):
"""Retrieve (or create, if not found) a Lexeme for a string, and return it.
Args
string (unicode): The string to be looked up. Must be unicode, not bytes.
Returns:
lexeme (Lexeme): A reference to a lexical type.
"""
cdef String string
string_from_unicode(&string, uni_string)
cdef Lexeme* lexeme = self.get(&string)
return lexeme[0]
cdef void string_from_unicode(String* s, unicode uni):
cdef Py_UNICODE* c_uni = <Py_UNICODE*>uni
string_slice(s, c_uni, 0, len(uni))
cdef inline void string_slice(String* s, Py_UNICODE* chars, int start, int end) nogil:
s.chars = &chars[start]
s.n = end - start
s.key = hash64(s.chars, s.n * sizeof(Py_UNICODE), 0)