Add support for Vietnamese in spaCy by leveraging Pyvi, an external Vietnamese tokenizer (#2155)

* support for Vietnamese

* Contributor Agreement for adding Vietnamese support on spaCy

.github/contributors/trungtv.md

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+# spaCy contributor agreement
+
+This spaCy Contributor Agreement (**"SCA"**) is based on the
+[Oracle Contributor Agreement](http://www.oracle.com/technetwork/oca-405177.pdf).
+The SCA applies to any contribution that you make to any product or project
+managed by us (the **"project"**), and sets out the intellectual property rights
+you grant to us in the contributed materials. The term **"us"** shall mean
+[ExplosionAI UG (haftungsbeschränkt)](https://explosion.ai/legal). The term
+**"you"** shall mean the person or entity identified below.
+
+If you agree to be bound by these terms, fill in the information requested
+below and include the filled-in version with your first pull request, under the
+folder [`.github/contributors/`](/.github/contributors/). The name of the file
+should be your GitHub username, with the extension `.md`. For example, the user
+example_user would create the file `.github/contributors/example_user.md`.
+
+Read this agreement carefully before signing. These terms and conditions
+constitute a binding legal agreement.
+
+## Contributor Agreement
+
+1. The term "contribution" or "contributed materials" means any source code,
+object code, patch, tool, sample, graphic, specification, manual,
+documentation, or any other material posted or submitted by you to the project.
+
+2. With respect to any worldwide copyrights, or copyright applications and
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+
+    * you hereby assign to us joint ownership, and to the extent that such
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+    contribution as if each of us were the sole owners, and if one of us makes
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+    * at our option, to sublicense these same rights to third parties through
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+4. Except as set out above, you keep all right, title, and interest in your
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+on the date you first submitted a contribution to us, even if your submission
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+
+5. You covenant, represent, warrant and agree that:
+
+    * Each contribution that you submit is and shall be an original work of
+    authorship and you can legally grant the rights set out in this SCA;
+
+    * to the best of your knowledge, each contribution will not violate any
+    third party's copyrights, trademarks, patents, or other intellectual
+    property rights; and
+
+    * each contribution shall be in compliance with U.S. export control laws and
+    other applicable export and import laws. You agree to notify us if you
+    become aware of any circumstance which would make any of the foregoing
+    representations inaccurate in any respect. We may publicly disclose your 
+    participation in the project, including the fact that you have signed the SCA.
+
+6. This SCA is governed by the laws of the State of California and applicable
+U.S. Federal law. Any choice of law rules will not apply.
+
+7. Please place an “x” on one of the applicable statement below. Please do NOT
+mark both statements:
+
+    * [x] I am signing on behalf of myself as an individual and no other person
+    or entity, including my employer, has or will have rights with respect to my
+    contributions.
+
+    * [ ] I am signing on behalf of my employer or a legal entity and I have the
+    actual authority to contractually bind that entity.
+
+## Contributor Details
+
+| Field                          | Entry                              |
+|------------------------------- | --------------------               |
+| Name                           | Viet-Trung Tran                    |
+| Company name (if applicable)   |   |
+| Title or role (if applicable)  |           |
+| Date                           | 2018-03-28                   |
+| GitHub username                | trungtv                           |
+| Website (optional)             | https://datalab.vn        |

spacy/lang/vi/__init__.py

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+# coding: utf8
+from __future__ import unicode_literals
+
+from ...attrs import LANG, NORM
+from ..norm_exceptions import BASE_NORMS
+from ...language import Language
+from ...tokens import Doc
+from .stop_words import STOP_WORDS
+from ...util import update_exc, add_lookups
+from .lex_attrs import LEX_ATTRS
+#from ..tokenizer_exceptions import BASE_EXCEPTIONS
+#from .tokenizer_exceptions import TOKENIZER_EXCEPTIONS
+
+
+class VietnameseDefaults(Language.Defaults):
+    lex_attr_getters = dict(Language.Defaults.lex_attr_getters)
+    lex_attr_getters[LANG] = lambda text: 'vi'  # for pickling
+    # add more norm exception dictionaries here
+    lex_attr_getters[NORM] = add_lookups(Language.Defaults.lex_attr_getters[NORM], BASE_NORMS)
+
+    # overwrite functions for lexical attributes
+    lex_attr_getters.update(LEX_ATTRS)
+
+    # merge base exceptions and custom tokenizer exceptions
+    #tokenizer_exceptions = update_exc(BASE_EXCEPTIONS, TOKENIZER_EXCEPTIONS)
+    stop_words = STOP_WORDS
+    use_pyvi = True
+
+class Vietnamese(Language):
+    lang = 'vi'
+    Defaults = VietnameseDefaults  # override defaults
+
+    def make_doc(self, text):
+        if self.Defaults.use_pyvi:
+            try:
+                from pyvi import ViTokenizer
+            except ImportError:
+                msg = ("Pyvi not installed. Either set Vietnamese.use_pyvi = False, "
+                       "or install it https://pypi.python.org/pypi/pyvi")
+                raise ImportError(msg)
+            words, spaces = ViTokenizer.spacy_tokenize(text)
+            return Doc(self.vocab, words=words, spaces=spaces)
+        else:
+            words = []
+            spaces = []
+            doc = self.tokenizer(text)
+            for token in self.tokenizer(text):
+                words.extend(list(token.text))
+                spaces.extend([False]*len(token.text))
+                spaces[-1] = bool(token.whitespace_)
+            return Doc(self.vocab, words=words, spaces=spaces)
+
+__all__ = ['Vietnamese']

spacy/lang/vi/lex_attrs.py

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+# coding: utf8
+from __future__ import unicode_literals
+
+from ...attrs import LIKE_NUM
+
+
+_num_words = ['không', 'một', 'hai', 'ba', 'bốn', 'năm', 'sáu', 'bẩy',
+              'tám', 'chín', 'mười', 'trăm', 'tỷ']
+
+
+def like_num(text):
+    text = text.replace(',', '').replace('.', '')
+    if text.isdigit():
+        return True
+    if text.count('/') == 1:
+        num, denom = text.split('/')
+        if num.isdigit() and denom.isdigit():
+            return True
+    if text.lower() in _num_words:
+        return True
+    return False
+
+
+LEX_ATTRS = {
+    LIKE_NUM: like_num
+}

spacy/lang/vi/tag_map.py

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+# coding: utf8
+from __future__ import unicode_literals
+
+from ..symbols import POS, ADV, NOUN, ADP, PRON, SCONJ, PROPN, DET, SYM, INTJ
+from ..symbols import PUNCT, NUM, AUX, X, CONJ, ADJ, VERB, PART, SPACE, CCONJ
+
+
+# Add a tag map
+# Documentation: https://spacy.io/docs/usage/adding-languages#tag-map
+# Universal Dependencies: http://universaldependencies.org/u/pos/all.html
+# The keys of the tag map should be strings in your tag set. The dictionary must
+# have an entry POS whose value is one of the Universal Dependencies tags.
+# Optionally, you can also include morphological features or other attributes.
+
+
+TAG_MAP = {
+    "ADV":      {POS: ADV},
+    "NOUN":     {POS: NOUN},
+    "ADP":      {POS: ADP},
+    "PRON":     {POS: PRON},
+    "SCONJ":    {POS: SCONJ},
+    "PROPN":    {POS: PROPN},
+    "DET":      {POS: DET},
+    "SYM":      {POS: SYM},
+    "INTJ":     {POS: INTJ},
+    "PUNCT":    {POS: PUNCT},
+    "NUM":      {POS: NUM},
+    "AUX":      {POS: AUX},
+    "X":        {POS: X},
+    "CONJ":     {POS: CONJ},
+    "CCONJ":    {POS: CCONJ},
+    "ADJ":      {POS: ADJ},
+    "VERB":     {POS: VERB},
+    "PART":     {POS: PART},
+    "SP":     	{POS: SPACE}
+}