spaCy/spacy/language.py

# coding: utf8
from __future__ import absolute_import, unicode_literals

import random
import itertools
from spacy.util import minibatch
import weakref
import functools
from collections import OrderedDict
from contextlib import contextmanager
from copy import copy, deepcopy
from thinc.neural import Model
import srsly
import multiprocessing as mp
from itertools import chain, cycle

from .tokenizer import Tokenizer
from .vocab import Vocab
from .lemmatizer import Lemmatizer
from .lookups import Lookups
from .analysis import analyze_pipes, analyze_all_pipes, validate_attrs
from .compat import izip, basestring_, is_python2, class_types
from .gold import GoldParse
from .scorer import Scorer
from ._ml import link_vectors_to_models, create_default_optimizer
from .attrs import IS_STOP, LANG
from .lang.punctuation import TOKENIZER_PREFIXES, TOKENIZER_SUFFIXES
from .lang.punctuation import TOKENIZER_INFIXES
from .lang.tokenizer_exceptions import TOKEN_MATCH
from .lang.tag_map import TAG_MAP
from .tokens import Doc
from .lang.lex_attrs import LEX_ATTRS, is_stop
from .errors import Errors, Warnings, deprecation_warning, user_warning
from . import util
from . import about


ENABLE_PIPELINE_ANALYSIS = False


class BaseDefaults(object):
    @classmethod
    def create_lemmatizer(cls, nlp=None, lookups=None):
        if lookups is None:
            lookups = cls.create_lookups(nlp=nlp)
        return Lemmatizer(lookups=lookups)

    @classmethod
    def create_lookups(cls, nlp=None):
        root = util.get_module_path(cls)
        filenames = {name: root / filename for name, filename in cls.resources}
        if LANG in cls.lex_attr_getters:
            lang = cls.lex_attr_getters[LANG](None)
            user_lookups = util.get_entry_point(util.ENTRY_POINTS.lookups, lang, {})
            filenames.update(user_lookups)
        lookups = Lookups()
        for name, filename in filenames.items():
            data = util.load_language_data(filename)
            lookups.add_table(name, data)
        return lookups

    @classmethod
    def create_vocab(cls, nlp=None):
        lookups = cls.create_lookups(nlp)
        lemmatizer = cls.create_lemmatizer(nlp, lookups=lookups)
        lex_attr_getters = dict(cls.lex_attr_getters)
        # This is messy, but it's the minimal working fix to Issue #639.
        lex_attr_getters[IS_STOP] = functools.partial(is_stop, stops=cls.stop_words)
        vocab = Vocab(
            lex_attr_getters=lex_attr_getters,
            tag_map=cls.tag_map,
            lemmatizer=lemmatizer,
            lookups=lookups,
        )
        for tag_str, exc in cls.morph_rules.items():
            for orth_str, attrs in exc.items():
                vocab.morphology.add_special_case(tag_str, orth_str, attrs)
        return vocab

    @classmethod
    def create_tokenizer(cls, nlp=None):
        rules = cls.tokenizer_exceptions
        token_match = cls.token_match
        prefix_search = (
            util.compile_prefix_regex(cls.prefixes).search if cls.prefixes else None
        )
        suffix_search = (
            util.compile_suffix_regex(cls.suffixes).search if cls.suffixes else None
        )
        infix_finditer = (
            util.compile_infix_regex(cls.infixes).finditer if cls.infixes else None
        )
        vocab = nlp.vocab if nlp is not None else cls.create_vocab(nlp)
        return Tokenizer(
            vocab,
            rules=rules,
            prefix_search=prefix_search,
            suffix_search=suffix_search,
            infix_finditer=infix_finditer,
            token_match=token_match,
        )

    pipe_names = ["tagger", "parser", "ner"]
    token_match = TOKEN_MATCH
    prefixes = tuple(TOKENIZER_PREFIXES)
    suffixes = tuple(TOKENIZER_SUFFIXES)
    infixes = tuple(TOKENIZER_INFIXES)
    tag_map = dict(TAG_MAP)
    tokenizer_exceptions = {}
    stop_words = set()
    morph_rules = {}
    lex_attr_getters = LEX_ATTRS
    syntax_iterators = {}
    resources = {}
    writing_system = {"direction": "ltr", "has_case": True, "has_letters": True}
    single_orth_variants = []
    paired_orth_variants = []


class Language(object):
    """A text-processing pipeline. Usually you'll load this once per process,
    and pass the instance around your application.

    Defaults (class): Settings, data and factory methods for creating the `nlp`
        object and processing pipeline.
    lang (unicode): Two-letter language ID, i.e. ISO code.

    DOCS: https://spacy.io/api/language
    """

    Defaults = BaseDefaults
    lang = None

    factories = {"tokenizer": lambda nlp: nlp.Defaults.create_tokenizer(nlp)}

    def __init__(
        self, vocab=True, make_doc=True, max_length=10 ** 6, meta={}, **kwargs
    ):
        """Initialise a Language object.

        vocab (Vocab): A `Vocab` object. If `True`, a vocab is created via
            `Language.Defaults.create_vocab`.
        make_doc (callable): A function that takes text and returns a `Doc`
            object. Usually a `Tokenizer`.
        meta (dict): Custom meta data for the Language class. Is written to by
            models to add model meta data.
        max_length (int) :
            Maximum number of characters in a single text. The current v2 models
            may run out memory on extremely long texts, due to large internal
            allocations. You should segment these texts into meaningful units,
            e.g. paragraphs, subsections etc, before passing them to spaCy.
            Default maximum length is 1,000,000 characters (1mb). As a rule of
            thumb, if all pipeline components are enabled, spaCy's default
            models currently requires roughly 1GB of temporary memory per
            100,000 characters in one text.
        RETURNS (Language): The newly constructed object.
        """
        user_factories = util.get_entry_points(util.ENTRY_POINTS.factories)
        self.factories.update(user_factories)
        self._meta = dict(meta)
        self._path = None
        if vocab is True:
            factory = self.Defaults.create_vocab
            vocab = factory(self, **meta.get("vocab", {}))
            if vocab.vectors.name is None:
                vocab.vectors.name = meta.get("vectors", {}).get("name")
        else:
            if (self.lang and vocab.lang) and (self.lang != vocab.lang):
                raise ValueError(Errors.E150.format(nlp=self.lang, vocab=vocab.lang))
        self.vocab = vocab
        if make_doc is True:
            factory = self.Defaults.create_tokenizer
            make_doc = factory(self, **meta.get("tokenizer", {}))
        self.tokenizer = make_doc
        self.pipeline = []
        self.max_length = max_length
        self._optimizer = None

    @property
    def path(self):
        return self._path

    @property
    def meta(self):
        if self.vocab.lang:
            self._meta.setdefault("lang", self.vocab.lang)
        else:
            self._meta.setdefault("lang", self.lang)
        self._meta.setdefault("name", "model")
        self._meta.setdefault("version", "0.0.0")
        self._meta.setdefault("spacy_version", ">={}".format(about.__version__))
        self._meta.setdefault("description", "")
        self._meta.setdefault("author", "")
        self._meta.setdefault("email", "")
        self._meta.setdefault("url", "")
        self._meta.setdefault("license", "")
        self._meta["vectors"] = {
            "width": self.vocab.vectors_length,
            "vectors": len(self.vocab.vectors),
            "keys": self.vocab.vectors.n_keys,
            "name": self.vocab.vectors.name,
        }
        self._meta["pipeline"] = self.pipe_names
        self._meta["factories"] = self.pipe_factories
        self._meta["labels"] = self.pipe_labels
        return self._meta

    @meta.setter
    def meta(self, value):
        self._meta = value

    # Conveniences to access pipeline components
    # Shouldn't be used anymore!
    @property
    def tensorizer(self):
        return self.get_pipe("tensorizer")

    @property
    def tagger(self):
        return self.get_pipe("tagger")

    @property
    def parser(self):
        return self.get_pipe("parser")

    @property
    def entity(self):
        return self.get_pipe("ner")

    @property
    def linker(self):
        return self.get_pipe("entity_linker")

    @property
    def matcher(self):
        return self.get_pipe("matcher")

    @property
    def pipe_names(self):
        """Get names of available pipeline components.

        RETURNS (list): List of component name strings, in order.
        """
        return [pipe_name for pipe_name, _ in self.pipeline]

    @property
    def pipe_factories(self):
        """Get the component factories for the available pipeline components.

        RETURNS (dict): Factory names, keyed by component names.
        """
        factories = {}
        for pipe_name, pipe in self.pipeline:
            factories[pipe_name] = getattr(pipe, "factory", pipe_name)
        return factories

    @property
    def pipe_labels(self):
        """Get the labels set by the pipeline components, if available (if
        the component exposes a labels property).

        RETURNS (dict): Labels keyed by component name.
        """
        labels = OrderedDict()
        for name, pipe in self.pipeline:
            if hasattr(pipe, "labels"):
                labels[name] = list(pipe.labels)
        return labels

    def get_pipe(self, name):
        """Get a pipeline component for a given component name.

        name (unicode): Name of pipeline component to get.
        RETURNS (callable): The pipeline component.

        DOCS: https://spacy.io/api/language#get_pipe
        """
        for pipe_name, component in self.pipeline:
            if pipe_name == name:
                return component
        raise KeyError(Errors.E001.format(name=name, opts=self.pipe_names))

    def create_pipe(self, name, config=dict()):
        """Create a pipeline component from a factory.

        name (unicode): Factory name to look up in `Language.factories`.
        config (dict): Configuration parameters to initialise component.
        RETURNS (callable): Pipeline component.

        DOCS: https://spacy.io/api/language#create_pipe
        """
        if name not in self.factories:
            if name == "sbd":
                raise KeyError(Errors.E108.format(name=name))
            else:
                raise KeyError(Errors.E002.format(name=name))
        factory = self.factories[name]
        return factory(self, **config)

    def add_pipe(
        self, component, name=None, before=None, after=None, first=None, last=None
    ):
        """Add a component to the processing pipeline. Valid components are
        callables that take a `Doc` object, modify it and return it. Only one
        of before/after/first/last can be set. Default behaviour is "last".

        component (callable): The pipeline component.
        name (unicode): Name of pipeline component. Overwrites existing
            component.name attribute if available. If no name is set and
            the component exposes no name attribute, component.__name__ is
            used. An error is raised if a name already exists in the pipeline.
        before (unicode): Component name to insert component directly before.
        after (unicode): Component name to insert component directly after.
        first (bool): Insert component first / not first in the pipeline.
        last (bool): Insert component last / not last in the pipeline.

        DOCS: https://spacy.io/api/language#add_pipe
        """
        if not hasattr(component, "__call__"):
            msg = Errors.E003.format(component=repr(component), name=name)
            if isinstance(component, basestring_) and component in self.factories:
                msg += Errors.E004.format(component=component)
            raise ValueError(msg)
        if name is None:
            name = util.get_component_name(component)
        if name in self.pipe_names:
            raise ValueError(Errors.E007.format(name=name, opts=self.pipe_names))
        if sum([bool(before), bool(after), bool(first), bool(last)]) >= 2:
            raise ValueError(Errors.E006)
        pipe_index = 0
        pipe = (name, component)
        if last or not any([first, before, after]):
            pipe_index = len(self.pipeline)
            self.pipeline.append(pipe)
        elif first:
            self.pipeline.insert(0, pipe)
        elif before and before in self.pipe_names:
            pipe_index = self.pipe_names.index(before)
            self.pipeline.insert(self.pipe_names.index(before), pipe)
        elif after and after in self.pipe_names:
            pipe_index = self.pipe_names.index(after) + 1
            self.pipeline.insert(self.pipe_names.index(after) + 1, pipe)
        else:
            raise ValueError(
                Errors.E001.format(name=before or after, opts=self.pipe_names)
            )
        if ENABLE_PIPELINE_ANALYSIS:
            analyze_pipes(self.pipeline, name, component, pipe_index)

    def has_pipe(self, name):
        """Check if a component name is present in the pipeline. Equivalent to
        `name in nlp.pipe_names`.

        name (unicode): Name of the component.
        RETURNS (bool): Whether a component of the name exists in the pipeline.

        DOCS: https://spacy.io/api/language#has_pipe
        """
        return name in self.pipe_names

    def replace_pipe(self, name, component):
        """Replace a component in the pipeline.

        name (unicode): Name of the component to replace.
        component (callable): Pipeline component.

        DOCS: https://spacy.io/api/language#replace_pipe
        """
        if name not in self.pipe_names:
            raise ValueError(Errors.E001.format(name=name, opts=self.pipe_names))
        if not hasattr(component, "__call__"):
            msg = Errors.E003.format(component=repr(component), name=name)
            if isinstance(component, basestring_) and component in self.factories:
                msg += Errors.E135.format(name=name)
            raise ValueError(msg)
        self.pipeline[self.pipe_names.index(name)] = (name, component)
        if ENABLE_PIPELINE_ANALYSIS:
            analyze_all_pipes(self.pipeline)

    def rename_pipe(self, old_name, new_name):
        """Rename a pipeline component.

        old_name (unicode): Name of the component to rename.
        new_name (unicode): New name of the component.

        DOCS: https://spacy.io/api/language#rename_pipe
        """
        if old_name not in self.pipe_names:
            raise ValueError(Errors.E001.format(name=old_name, opts=self.pipe_names))
        if new_name in self.pipe_names:
            raise ValueError(Errors.E007.format(name=new_name, opts=self.pipe_names))
        i = self.pipe_names.index(old_name)
        self.pipeline[i] = (new_name, self.pipeline[i][1])

    def remove_pipe(self, name):
        """Remove a component from the pipeline.

        name (unicode): Name of the component to remove.
        RETURNS (tuple): A `(name, component)` tuple of the removed component.

        DOCS: https://spacy.io/api/language#remove_pipe
        """
        if name not in self.pipe_names:
            raise ValueError(Errors.E001.format(name=name, opts=self.pipe_names))
        removed = self.pipeline.pop(self.pipe_names.index(name))
        if ENABLE_PIPELINE_ANALYSIS:
            analyze_all_pipes(self.pipeline)
        return removed

    def __call__(self, text, disable=[], component_cfg=None):
        """Apply the pipeline to some text. The text can span multiple sentences,
        and can contain arbtrary whitespace. Alignment into the original string
        is preserved.

        text (unicode): The text to be processed.
        disable (list): Names of the pipeline components to disable.
        component_cfg (dict): An optional dictionary with extra keyword arguments
            for specific components.
        RETURNS (Doc): A container for accessing the annotations.

        DOCS: https://spacy.io/api/language#call
        """
        if len(text) > self.max_length:
            raise ValueError(
                Errors.E088.format(length=len(text), max_length=self.max_length)
            )
        doc = self.make_doc(text)
        if component_cfg is None:
            component_cfg = {}
        for name, proc in self.pipeline:
            if name in disable:
                continue
            if not hasattr(proc, "__call__"):
                raise ValueError(Errors.E003.format(component=type(proc), name=name))
            doc = proc(doc, **component_cfg.get(name, {}))
            if doc is None:
                raise ValueError(Errors.E005.format(name=name))
        return doc

    def disable_pipes(self, *names):
        """Disable one or more pipeline components. If used as a context
        manager, the pipeline will be restored to the initial state at the end
        of the block. Otherwise, a DisabledPipes object is returned, that has
        a `.restore()` method you can use to undo your changes.

        DOCS: https://spacy.io/api/language#disable_pipes
        """
        if len(names) == 1 and isinstance(names[0], (list, tuple)):
            names = names[0]  # support list of names instead of spread
        return DisabledPipes(self, *names)

    def make_doc(self, text):
        return self.tokenizer(text)

    def _format_docs_and_golds(self, docs, golds):
        """Format golds and docs before update models."""
        expected_keys = ("words", "tags", "heads", "deps", "entities", "cats", "links")
        gold_objs = []
        doc_objs = []
        for doc, gold in zip(docs, golds):
            if isinstance(doc, basestring_):
                doc = self.make_doc(doc)
            if not isinstance(gold, GoldParse):
                unexpected = [k for k in gold if k not in expected_keys]
                if unexpected:
                    err = Errors.E151.format(unexp=unexpected, exp=expected_keys)
                    raise ValueError(err)
                gold = GoldParse(doc, **gold)
            doc_objs.append(doc)
            gold_objs.append(gold)

        return doc_objs, gold_objs

    def update(self, docs, golds, drop=0.0, sgd=None, losses=None, component_cfg=None):
        """Update the models in the pipeline.

        docs (iterable): A batch of `Doc` objects.
        golds (iterable): A batch of `GoldParse` objects.
        drop (float): The dropout rate.
        sgd (callable): An optimizer.
        losses (dict): Dictionary to update with the loss, keyed by component.
        component_cfg (dict): Config parameters for specific pipeline
            components, keyed by component name.

        DOCS: https://spacy.io/api/language#update
        """
        if len(docs) != len(golds):
            raise IndexError(Errors.E009.format(n_docs=len(docs), n_golds=len(golds)))
        if len(docs) == 0:
            return
        if sgd is None:
            if self._optimizer is None:
                self._optimizer = create_default_optimizer(Model.ops)
            sgd = self._optimizer
        # Allow dict of args to GoldParse, instead of GoldParse objects.
        docs, golds = self._format_docs_and_golds(docs, golds)
        grads = {}

        def get_grads(W, dW, key=None):
            grads[key] = (W, dW)

        get_grads.alpha = sgd.alpha
        get_grads.b1 = sgd.b1
        get_grads.b2 = sgd.b2
        pipes = list(self.pipeline)
        random.shuffle(pipes)
        if component_cfg is None:
            component_cfg = {}
        for name, proc in pipes:
            if not hasattr(proc, "update"):
                continue
            grads = {}
            kwargs = component_cfg.get(name, {})
            kwargs.setdefault("drop", drop)
            proc.update(docs, golds, sgd=get_grads, losses=losses, **kwargs)
            for key, (W, dW) in grads.items():
                sgd(W, dW, key=key)

    def rehearse(self, docs, sgd=None, losses=None, config=None):
        """Make a "rehearsal" update to the models in the pipeline, to prevent
        forgetting. Rehearsal updates run an initial copy of the model over some
        data, and update the model so its current predictions are more like the
        initial ones. This is useful for keeping a pretrained model on-track,
        even if you're updating it with a smaller set of examples.

        docs (iterable): A batch of `Doc` objects.
        drop (float): The dropout rate.
        sgd (callable): An optimizer.
        RETURNS (dict): Results from the update.

        EXAMPLE:
            >>> raw_text_batches = minibatch(raw_texts)
            >>> for labelled_batch in minibatch(zip(train_docs, train_golds)):
            >>>     docs, golds = zip(*train_docs)
            >>>     nlp.update(docs, golds)
            >>>     raw_batch = [nlp.make_doc(text) for text in next(raw_text_batches)]
            >>>     nlp.rehearse(raw_batch)
        """
        # TODO: document
        if len(docs) == 0:
            return
        if sgd is None:
            if self._optimizer is None:
                self._optimizer = create_default_optimizer(Model.ops)
            sgd = self._optimizer
        docs = list(docs)
        for i, doc in enumerate(docs):
            if isinstance(doc, basestring_):
                docs[i] = self.make_doc(doc)
        pipes = list(self.pipeline)
        random.shuffle(pipes)
        if config is None:
            config = {}
        grads = {}

        def get_grads(W, dW, key=None):
            grads[key] = (W, dW)

        get_grads.alpha = sgd.alpha
        get_grads.b1 = sgd.b1
        get_grads.b2 = sgd.b2
        for name, proc in pipes:
            if not hasattr(proc, "rehearse"):
                continue
            grads = {}
            proc.rehearse(docs, sgd=get_grads, losses=losses, **config.get(name, {}))
            for key, (W, dW) in grads.items():
                sgd(W, dW, key=key)
        return losses

    def preprocess_gold(self, docs_golds):
        """Can be called before training to pre-process gold data. By default,
        it handles nonprojectivity and adds missing tags to the tag map.

        docs_golds (iterable): Tuples of `Doc` and `GoldParse` objects.
        YIELDS (tuple): Tuples of preprocessed `Doc` and `GoldParse` objects.
        """
        for name, proc in self.pipeline:
            if hasattr(proc, "preprocess_gold"):
                docs_golds = proc.preprocess_gold(docs_golds)
        for doc, gold in docs_golds:
            yield doc, gold

    def begin_training(self, get_gold_tuples=None, sgd=None, component_cfg=None, **cfg):
        """Allocate models, pre-process training data and acquire a trainer and
        optimizer. Used as a contextmanager.

        get_gold_tuples (function): Function returning gold data
        component_cfg (dict): Config parameters for specific components.
        **cfg: Config parameters.
        RETURNS: An optimizer.

        DOCS: https://spacy.io/api/language#begin_training
        """
        if get_gold_tuples is None:
            get_gold_tuples = lambda: []
        # Populate vocab
        else:
            for _, annots_brackets in get_gold_tuples():
                _ = annots_brackets.pop()
                for annots, _ in annots_brackets:
                    for word in annots[1]:
                        _ = self.vocab[word]  # noqa: F841
        if cfg.get("device", -1) >= 0:
            util.use_gpu(cfg["device"])
            if self.vocab.vectors.data.shape[1] >= 1:
                self.vocab.vectors.data = Model.ops.asarray(self.vocab.vectors.data)
        link_vectors_to_models(self.vocab)
        if self.vocab.vectors.data.shape[1]:
            cfg["pretrained_vectors"] = self.vocab.vectors.name
        if sgd is None:
            sgd = create_default_optimizer(Model.ops)
        self._optimizer = sgd
        if component_cfg is None:
            component_cfg = {}
        for name, proc in self.pipeline:
            if hasattr(proc, "begin_training"):
                kwargs = component_cfg.get(name, {})
                kwargs.update(cfg)
                proc.begin_training(
                    get_gold_tuples,
                    pipeline=self.pipeline,
                    sgd=self._optimizer,
                    **kwargs
                )
        return self._optimizer

    def resume_training(self, sgd=None, **cfg):
        """Continue training a pretrained model.

        Create and return an optimizer, and initialize "rehearsal" for any pipeline
        component that has a .rehearse() method. Rehearsal is used to prevent
        models from "forgetting" their initialised "knowledge". To perform
        rehearsal, collect samples of text you want the models to retain performance
        on, and call nlp.rehearse() with a batch of Doc objects.
        """
        if cfg.get("device", -1) >= 0:
            util.use_gpu(cfg["device"])
            if self.vocab.vectors.data.shape[1] >= 1:
                self.vocab.vectors.data = Model.ops.asarray(self.vocab.vectors.data)
        link_vectors_to_models(self.vocab)
        if self.vocab.vectors.data.shape[1]:
            cfg["pretrained_vectors"] = self.vocab.vectors.name
        if sgd is None:
            sgd = create_default_optimizer(Model.ops)
        self._optimizer = sgd
        for name, proc in self.pipeline:
            if hasattr(proc, "_rehearsal_model"):
                proc._rehearsal_model = deepcopy(proc.model)
        return self._optimizer

    def evaluate(
        self, docs_golds, verbose=False, batch_size=256, scorer=None, component_cfg=None
    ):
        """Evaluate a model's pipeline components.

        docs_golds (iterable): Tuples of `Doc` and `GoldParse` objects.
        verbose (bool): Print debugging information.
        batch_size (int): Batch size to use.
        scorer (Scorer): Optional `Scorer` to use. If not passed in, a new one
            will be created.
        component_cfg (dict): An optional dictionary with extra keyword
            arguments for specific components.
        RETURNS (Scorer): The scorer containing the evaluation results.

        DOCS: https://spacy.io/api/language#evaluate
        """
        if scorer is None:
            scorer = Scorer(pipeline=self.pipeline)
        if component_cfg is None:
            component_cfg = {}
        docs, golds = zip(*docs_golds)
        docs = [
            self.make_doc(doc) if isinstance(doc, basestring_) else doc for doc in docs
        ]
        golds = list(golds)
        for name, pipe in self.pipeline:
            kwargs = component_cfg.get(name, {})
            kwargs.setdefault("batch_size", batch_size)
            if not hasattr(pipe, "pipe"):
                docs = _pipe(pipe, docs, kwargs)
            else:
                docs = pipe.pipe(docs, **kwargs)
        for doc, gold in zip(docs, golds):
            if not isinstance(gold, GoldParse):
                gold = GoldParse(doc, **gold)
            if verbose:
                print(doc)
            kwargs = component_cfg.get("scorer", {})
            kwargs.setdefault("verbose", verbose)
            scorer.score(doc, gold, **kwargs)
        return scorer

    @contextmanager
    def use_params(self, params, **cfg):
        """Replace weights of models in the pipeline with those provided in the
        params dictionary. Can be used as a contextmanager, in which case,
        models go back to their original weights after the block.

        params (dict): A dictionary of parameters keyed by model ID.
        **cfg: Config parameters.

        EXAMPLE:
            >>> with nlp.use_params(optimizer.averages):
            >>>     nlp.to_disk('/tmp/checkpoint')
        """
        contexts = [
            pipe.use_params(params)
            for name, pipe in self.pipeline
            if hasattr(pipe, "use_params")
        ]
        # TODO: Having trouble with contextlib
        # Workaround: these aren't actually context managers atm.
        for context in contexts:
            try:
                next(context)
            except StopIteration:
                pass
        yield
        for context in contexts:
            try:
                next(context)
            except StopIteration:
                pass

    def pipe(
        self,
        texts,
        as_tuples=False,
        n_threads=-1,
        batch_size=1000,
        disable=[],
        cleanup=False,
        component_cfg=None,
        n_process=1,
    ):
        """Process texts as a stream, and yield `Doc` objects in order.

        texts (iterator): A sequence of texts to process.
        as_tuples (bool): If set to True, inputs should be a sequence of
            (text, context) tuples. Output will then be a sequence of
            (doc, context) tuples. Defaults to False.
        batch_size (int): The number of texts to buffer.
        disable (list): Names of the pipeline components to disable.
        cleanup (bool): If True, unneeded strings are freed to control memory
            use. Experimental.
        component_cfg (dict): An optional dictionary with extra keyword
            arguments for specific components.
        n_process (int): Number of processors to process texts, only supported
            in Python3. If -1, set `multiprocessing.cpu_count()`.
        YIELDS (Doc): Documents in the order of the original text.

        DOCS: https://spacy.io/api/language#pipe
        """
        # raw_texts will be used later to stop iterator.
        texts, raw_texts = itertools.tee(texts)
        if is_python2 and n_process != 1:
            user_warning(Warnings.W023)
            n_process = 1
        if n_threads != -1:
            deprecation_warning(Warnings.W016)
        if n_process == -1:
            n_process = mp.cpu_count()
        if as_tuples:
            text_context1, text_context2 = itertools.tee(texts)
            texts = (tc[0] for tc in text_context1)
            contexts = (tc[1] for tc in text_context2)
            docs = self.pipe(
                texts,
                batch_size=batch_size,
                disable=disable,
                component_cfg=component_cfg,
            )
            for doc, context in izip(docs, contexts):
                yield (doc, context)
            return
        if component_cfg is None:
            component_cfg = {}

        pipes = (
            []
        )  # contains functools.partial objects so that easily create multiprocess worker.
        for name, proc in self.pipeline:
            if name in disable:
                continue
            kwargs = component_cfg.get(name, {})
            # Allow component_cfg to overwrite the top-level kwargs.
            kwargs.setdefault("batch_size", batch_size)
            if hasattr(proc, "pipe"):
                f = functools.partial(proc.pipe, **kwargs)
            else:
                # Apply the function, but yield the doc
                f = functools.partial(_pipe, proc=proc, kwargs=kwargs)
            pipes.append(f)

        if n_process != 1:
            docs = self._multiprocessing_pipe(texts, pipes, n_process, batch_size)
        else:
            # if n_process == 1, no processes are forked.
            docs = (self.make_doc(text) for text in texts)
            for pipe in pipes:
                docs = pipe(docs)

        # Track weakrefs of "recent" documents, so that we can see when they
        # expire from memory. When they do, we know we don't need old strings.
        # This way, we avoid maintaining an unbounded growth in string entries
        # in the string store.
        recent_refs = weakref.WeakSet()
        old_refs = weakref.WeakSet()
        # Keep track of the original string data, so that if we flush old strings,
        # we can recover the original ones. However, we only want to do this if we're
        # really adding strings, to save up-front costs.
        original_strings_data = None
        nr_seen = 0
        for doc in docs:
            yield doc
            if cleanup:
                recent_refs.add(doc)
                if nr_seen < 10000:
                    old_refs.add(doc)
                    nr_seen += 1
                elif len(old_refs) == 0:
                    old_refs, recent_refs = recent_refs, old_refs
                    if original_strings_data is None:
                        original_strings_data = list(self.vocab.strings)
                    else:
                        keys, strings = self.vocab.strings._cleanup_stale_strings(
                            original_strings_data
                        )
                        self.vocab._reset_cache(keys, strings)
                        self.tokenizer._reset_cache(keys)
                    nr_seen = 0

    def _multiprocessing_pipe(self, texts, pipes, n_process, batch_size):
        # raw_texts is used later to stop iteration.
        texts, raw_texts = itertools.tee(texts)
        # for sending texts to worker
        texts_q = [mp.Queue() for _ in range(n_process)]
        # for receiving byte encoded docs from worker
        bytedocs_recv_ch, bytedocs_send_ch = zip(
            *[mp.Pipe(False) for _ in range(n_process)]
        )

        batch_texts = minibatch(texts, batch_size)
        # Sender sends texts to the workers.
        # This is necessary to properly handle infinite length of texts.
        # (In this case, all data cannot be sent to the workers at once)
        sender = _Sender(batch_texts, texts_q, chunk_size=n_process)
        # send twice so that make process busy
        sender.send()
        sender.send()

        procs = [
            mp.Process(target=_apply_pipes, args=(self.make_doc, pipes, rch, sch))
            for rch, sch in zip(texts_q, bytedocs_send_ch)
        ]
        for proc in procs:
            proc.start()

        # Cycle channels not to break the order of docs.
        # The received object is batch of byte encoded docs, so flatten them with chain.from_iterable.
        byte_docs = chain.from_iterable(recv.recv() for recv in cycle(bytedocs_recv_ch))
        docs = (Doc(self.vocab).from_bytes(byte_doc) for byte_doc in byte_docs)
        try:
            for i, (_, doc) in enumerate(zip(raw_texts, docs), 1):
                yield doc
                if i % batch_size == 0:
                    # tell `sender` that one batch was consumed.
                    sender.step()
        finally:
            for proc in procs:
                proc.terminate()

    def to_disk(self, path, exclude=tuple(), disable=None):
        """Save the current state to a directory.  If a model is loaded, this
        will include the model.

        path (unicode or Path): Path to a directory, which will be created if
            it doesn't exist.
        exclude (list): Names of components or serialization fields to exclude.

        DOCS: https://spacy.io/api/language#to_disk
        """
        if disable is not None:
            deprecation_warning(Warnings.W014)
            exclude = disable
        path = util.ensure_path(path)
        serializers = OrderedDict()
        serializers["tokenizer"] = lambda p: self.tokenizer.to_disk(
            p, exclude=["vocab"]
        )
        serializers["meta.json"] = lambda p: p.open("w").write(
            srsly.json_dumps(self.meta)
        )
        for name, proc in self.pipeline:
            if not hasattr(proc, "name"):
                continue
            if name in exclude:
                continue
            if not hasattr(proc, "to_disk"):
                continue
            serializers[name] = lambda p, proc=proc: proc.to_disk(p, exclude=["vocab"])
        serializers["vocab"] = lambda p: self.vocab.to_disk(p)
        util.to_disk(path, serializers, exclude)

    def from_disk(self, path, exclude=tuple(), disable=None):
        """Loads state from a directory. Modifies the object in place and
        returns it. If the saved `Language` object contains a model, the
        model will be loaded.

        path (unicode or Path): A path to a directory.
        exclude (list): Names of components or serialization fields to exclude.
        RETURNS (Language): The modified `Language` object.

        DOCS: https://spacy.io/api/language#from_disk
        """
        if disable is not None:
            deprecation_warning(Warnings.W014)
            exclude = disable
        path = util.ensure_path(path)
        deserializers = OrderedDict()
        deserializers["meta.json"] = lambda p: self.meta.update(srsly.read_json(p))
        deserializers["vocab"] = lambda p: self.vocab.from_disk(
            p
        ) and _fix_pretrained_vectors_name(self)
        deserializers["tokenizer"] = lambda p: self.tokenizer.from_disk(
            p, exclude=["vocab"]
        )
        for name, proc in self.pipeline:
            if name in exclude:
                continue
            if not hasattr(proc, "from_disk"):
                continue
            deserializers[name] = lambda p, proc=proc: proc.from_disk(
                p, exclude=["vocab"]
            )
        if not (path / "vocab").exists() and "vocab" not in exclude:
            # Convert to list here in case exclude is (default) tuple
            exclude = list(exclude) + ["vocab"]
        util.from_disk(path, deserializers, exclude)
        self._path = path
        return self

    def to_bytes(self, exclude=tuple(), disable=None, **kwargs):
        """Serialize the current state to a binary string.

        exclude (list): Names of components or serialization fields to exclude.
        RETURNS (bytes): The serialized form of the `Language` object.

        DOCS: https://spacy.io/api/language#to_bytes
        """
        if disable is not None:
            deprecation_warning(Warnings.W014)
            exclude = disable
        serializers = OrderedDict()
        serializers["vocab"] = lambda: self.vocab.to_bytes()
        serializers["tokenizer"] = lambda: self.tokenizer.to_bytes(exclude=["vocab"])
        serializers["meta.json"] = lambda: srsly.json_dumps(self.meta)
        for name, proc in self.pipeline:
            if name in exclude:
                continue
            if not hasattr(proc, "to_bytes"):
                continue
            serializers[name] = lambda proc=proc: proc.to_bytes(exclude=["vocab"])
        exclude = util.get_serialization_exclude(serializers, exclude, kwargs)
        return util.to_bytes(serializers, exclude)

    def from_bytes(self, bytes_data, exclude=tuple(), disable=None, **kwargs):
        """Load state from a binary string.

        bytes_data (bytes): The data to load from.
        exclude (list): Names of components or serialization fields to exclude.
        RETURNS (Language): The `Language` object.

        DOCS: https://spacy.io/api/language#from_bytes
        """
        if disable is not None:
            deprecation_warning(Warnings.W014)
            exclude = disable
        deserializers = OrderedDict()
        deserializers["meta.json"] = lambda b: self.meta.update(srsly.json_loads(b))
        deserializers["vocab"] = lambda b: self.vocab.from_bytes(
            b
        ) and _fix_pretrained_vectors_name(self)
        deserializers["tokenizer"] = lambda b: self.tokenizer.from_bytes(
            b, exclude=["vocab"]
        )
        for name, proc in self.pipeline:
            if name in exclude:
                continue
            if not hasattr(proc, "from_bytes"):
                continue
            deserializers[name] = lambda b, proc=proc: proc.from_bytes(
                b, exclude=["vocab"]
            )
        exclude = util.get_serialization_exclude(deserializers, exclude, kwargs)
        util.from_bytes(bytes_data, deserializers, exclude)
        return self


class component(object):
    """Decorator for pipeline components. Can decorate both function components
    and class components and will automatically register components in the
    Language.factories. If the component is a class and needs access to the
    nlp object or config parameters, it can expose a from_nlp classmethod
    that takes the nlp object and **cfg arguments and returns the initialized
    component.
    """

    # NB: This decorator needs to live here, because it needs to write to
    # Language.factories. All other solutions would cause circular import.

    def __init__(self, name=None, assigns=tuple(), requires=tuple(), retokenizes=False):
        """Decorate a pipeline component.

        name (unicode): Default component and factory name.
        assigns (list): Attributes assigned by component, e.g. `["token.pos"]`.
        requires (list): Attributes required by component, e.g. `["token.dep"]`.
        retokenizes (bool): Whether the component changes the tokenization.
        """
        self.name = name
        self.assigns = validate_attrs(assigns)
        self.requires = validate_attrs(requires)
        self.retokenizes = retokenizes

    def __call__(self, *args, **kwargs):
        obj = args[0]
        args = args[1:]
        factory_name = self.name or util.get_component_name(obj)
        obj.name = factory_name
        obj.factory = factory_name
        obj.assigns = self.assigns
        obj.requires = self.requires
        obj.retokenizes = self.retokenizes

        def factory(nlp, **cfg):
            if hasattr(obj, "from_nlp"):
                return obj.from_nlp(nlp, **cfg)
            elif isinstance(obj, class_types):
                return obj()
            return obj

        Language.factories[obj.factory] = factory
        return obj


def _fix_pretrained_vectors_name(nlp):
    # TODO: Replace this once we handle vectors consistently as static
    # data
    if "vectors" in nlp.meta and nlp.meta["vectors"].get("name"):
        nlp.vocab.vectors.name = nlp.meta["vectors"]["name"]
    elif not nlp.vocab.vectors.size:
        nlp.vocab.vectors.name = None
    elif "name" in nlp.meta and "lang" in nlp.meta:
        vectors_name = "%s_%s.vectors" % (nlp.meta["lang"], nlp.meta["name"])
        nlp.vocab.vectors.name = vectors_name
    else:
        raise ValueError(Errors.E092)
    if nlp.vocab.vectors.size != 0:
        link_vectors_to_models(nlp.vocab)
    for name, proc in nlp.pipeline:
        if not hasattr(proc, "cfg"):
            continue
        proc.cfg.setdefault("deprecation_fixes", {})
        proc.cfg["deprecation_fixes"]["vectors_name"] = nlp.vocab.vectors.name


class DisabledPipes(list):
    """Manager for temporary pipeline disabling."""

    def __init__(self, nlp, *names):
        self.nlp = nlp
        self.names = names
        # Important! Not deep copy -- we just want the container (but we also
        # want to support people providing arbitrarily typed nlp.pipeline
        # objects.)
        self.original_pipeline = copy(nlp.pipeline)
        list.__init__(self)
        self.extend(nlp.remove_pipe(name) for name in names)

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self.restore()

    def restore(self):
        """Restore the pipeline to its state when DisabledPipes was created."""
        current, self.nlp.pipeline = self.nlp.pipeline, self.original_pipeline
        unexpected = [name for name, pipe in current if not self.nlp.has_pipe(name)]
        if unexpected:
            # Don't change the pipeline if we're raising an error.
            self.nlp.pipeline = current
            raise ValueError(Errors.E008.format(names=unexpected))
        self[:] = []


def _pipe(docs, proc, kwargs):
    # We added some args for pipe that __call__ doesn't expect.
    kwargs = dict(kwargs)
    for arg in ["n_threads", "batch_size"]:
        if arg in kwargs:
            kwargs.pop(arg)
    for doc in docs:
        doc = proc(doc, **kwargs)
        yield doc


def _apply_pipes(make_doc, pipes, reciever, sender):
    """Worker for Language.pipe

    receiver (multiprocessing.Connection): Pipe to receive text. Usually
        created by `multiprocessing.Pipe()`
    sender (multiprocessing.Connection): Pipe to send doc. Usually created by
        `multiprocessing.Pipe()`
    """
    while True:
        texts = reciever.get()
        docs = (make_doc(text) for text in texts)
        for pipe in pipes:
            docs = pipe(docs)
        # Connection does not accept unpickable objects, so send list.
        sender.send([doc.to_bytes() for doc in docs])


class _Sender:
    """Util for sending data to multiprocessing workers in Language.pipe"""

    def __init__(self, data, queues, chunk_size):
        self.data = iter(data)
        self.queues = iter(cycle(queues))
        self.chunk_size = chunk_size
        self.count = 0

    def send(self):
        """Send chunk_size items from self.data to channels."""
        for item, q in itertools.islice(
            zip(self.data, cycle(self.queues)), self.chunk_size
        ):
            # cycle channels so that distribute the texts evenly
            q.put(item)

    def step(self):
        """Tell sender that comsumed one item.

        Data is sent to the workers after every chunk_size calls."""
        self.count += 1
        if self.count >= self.chunk_size:
            self.count = 0
            self.send()