Adding basic support for Sinhala language. (#2788)

* adding Sinhala language package, stop words, examples and lex_attrs.

* Adding contributor agreement

* Updating contributor agreement

.github/contributors/keshan.md

@@ -0,0 +1,106 @@
+# 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
+registrations, in your contribution:
+
+    * you hereby assign to us joint ownership, and to the extent that such
+    assignment is or becomes invalid, ineffective or unenforceable, you hereby
+    grant to us a perpetual, irrevocable, non-exclusive, worldwide, no-charge,
+    royalty-free, unrestricted license to exercise all rights under those
+    copyrights. This includes, at our option, the right to sublicense these same
+    rights to third parties through multiple levels of sublicensees or other
+    licensing arrangements;
+
+    * you agree that each of us can do all things in relation to your
+    contribution as if each of us were the sole owners, and if one of us makes
+    a derivative work of your contribution, the one who makes the derivative
+    work (or has it made will be the sole owner of that derivative work;
+
+    * you agree that you will not assert any moral rights in your contribution
+    against us, our licensees or transferees;
+
+    * you agree that we may register a copyright in your contribution and
+    exercise all ownership rights associated with it; and
+
+    * you agree that neither of us has any duty to consult with, obtain the
+    consent of, pay or render an accounting to the other for any use or
+    distribution of your contribution.
+
+3. With respect to any patents you own, or that you can license without payment
+to any third party, you hereby grant to us a perpetual, irrevocable,
+non-exclusive, worldwide, no-charge, royalty-free license to:
+
+    * make, have made, use, sell, offer to sell, import, and otherwise transfer
+    your contribution in whole or in part, alone or in combination with or
+    included in any product, work or materials arising out of the project to
+    which your contribution was submitted, and
+
+    * at our option, to sublicense these same rights to third parties through
+    multiple levels of sublicensees or other licensing arrangements.
+
+4. Except as set out above, you keep all right, title, and interest in your
+contribution. The rights that you grant to us under these terms are effective
+on the date you first submitted a contribution to us, even if your submission
+took place before the date you sign these terms.
+
+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                           | Keshan Sodimana |
+| Company name (if applicable)   |                      |
+| Title or role (if applicable)  |                      |
+| Date                           | Sep 21, 2018  |
+| GitHub username                | keshan     |
+| Website (optional)             |                      |

spacy/lang/char_classes.py

@@ -16,6 +16,7 @@ _latin = r'[[\p{Ll}||\p{Lu}]&&\p{Latin}]'
 _persian = r'[\p{L}&&\p{Arabic}]'
 _russian_lower = r'[ёа-я]'
 _russian_upper = r'[ЁА-Я]'
+_sinhala = r'[\p{L}&&\p{Sinhala}]'
 _tatar_lower = r'[әөүҗңһ]'
 _tatar_upper = r'[ӘӨҮҖҢҺ]'
 _greek_lower = r'[α-ωάέίόώήύ]'
@@ -23,7 +24,7 @@ _greek_upper = r'[Α-ΩΆΈΊΌΏΉΎ]'
 
 _upper = [_latin_upper, _russian_upper, _tatar_upper, _greek_upper]
 _lower = [_latin_lower, _russian_lower, _tatar_lower, _greek_lower]
-_uncased = [_bengali, _hebrew, _persian]
+_uncased = [_bengali, _hebrew, _persian, _sinhala]
 
 ALPHA = merge_char_classes(_upper + _lower + _uncased)
 ALPHA_LOWER = merge_char_classes(_lower + _uncased)

spacy/lang/si/__init__.py

@@ -0,0 +1,23 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+from .stop_words import STOP_WORDS
+from .lex_attrs import LEX_ATTRS
+
+from ...language import Language
+from ...attrs import LANG
+
+
+class SinhalaDefaults(Language.Defaults):
+    lex_attr_getters = dict(Language.Defaults.lex_attr_getters)
+    lex_attr_getters.update(LEX_ATTRS)
+    lex_attr_getters[LANG] = lambda text: 'si'
+    stop_words = STOP_WORDS
+
+
+class Sinhala(Language):
+    lang = 'si'
+    Defaults = SinhalaDefaults
+
+
+__all__ = ['Sinhala']

spacy/lang/si/examples.py

@@ -0,0 +1,22 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+
+"""
+Example sentences to test spaCy and its language models.
+
+>>> from spacy.lang.si.examples import sentences
+>>> docs = nlp.pipe(sentences)
+"""
+
+
+sentences = [
+    "ඔබ කවුද?",
+    "ගූගල් සමාගම ඩොලර් මිලියන 500 කට එම ආයතනය මිලදී ගන්නා ලදී.",
+    "කොළඹ ශ්‍රී ලංකාවේ ප්‍රධානතම නගරය යි.",
+    "ප්‍රංශයේ ජනාධිපති කවරෙක් ද?",
+    "මට බිස්කට් 1 ක් දෙන්න",
+    "ඔවුන් ලකුණු 59 කින් තරඟය පරාජයට පත් විය.",
+    "1 ත් 10 ත් අතර සංඛ්‍යාවක් කියන්න",
+    "ඔහු සහ ඇය නුවර හෝ කොළඹ පදිංචි කරුවන් නොවේ",
+]

spacy/lang/si/lex_attrs.py

@@ -0,0 +1,28 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+from ...attrs import LIKE_NUM
+
+_num_words = ['බින්දුව', 'බිංදුව', 'එක', 'දෙක', 'තුන', 'හතර', 'පහ', 'හය', 'හත',
+              'අට', 'නවය', 'නමය', 'දහය', 'එකොළහ', 'දොළහ', 'දහතුන', 'දහහතර',
+              'දාහතර', 'පහළව', 'පහළොව', 'දහසය', 'දහහත', 'දාහත', 'දහඅට',
+              'දහනවය', 'විස්ස', 'තිහ', 'හතළිහ', 'පනහ', 'හැට', 'හැත්තෑව', 'අසූව',
+              'අනූව', 'සියය', 'දහස', 'දාහ', 'ලක්ෂය', 'මිලියනය', 'කෝටිය',
+              'බිලියනය', 'ට්‍රිලියනය']
+
+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/si/stop_words.py

@@ -0,0 +1,51 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+
+# Stop words
+
+STOP_WORDS = set("""
+අතර
+එච්චර
+එපමණ
+එලෙස
+එවිට
+ඒ
+කට
+කදී
+කින්
+ක්
+ට
+තුර
+ත්
+ද
+නමුත්
+නොහොත්
+පමණ
+පමණි
+ම
+මෙච්චර
+මෙපමණ
+මෙලෙස
+මෙවිට
+මේ
+ය
+යි
+ලදී
+ලෙස
+වගේ
+වන
+විට
+විටෙක
+විතර
+විය
+වුව
+වුවත්
+වුවද
+වූ
+සමඟ
+සහ
+හා
+හෙවත්
+හෝ  
+""".split())