Initial implementation of MessageContext

fluent/context.py

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+from __future__ import absolute_import, unicode_literals
+
+import six
+
+from .syntax import FluentParser
+from .syntax.ast import Message, Term
+
+
+class MessageContext(object):
+    """
+    Message contexts are single-language stores of translations.  They are
+    responsible for parsing translation resources in the Fluent syntax and can
+    format translation units (entities) to strings.
+
+    Always use `MessageContext.format` to retrieve translation units from
+    a context.  Translations can contain references to other entities or
+    external arguments, conditional logic in form of select expressions, traits
+    which describe their grammatical features, and can use Fluent builtins.
+    See the documentation of the Fluent syntax for more information.
+    """
+
+    def __init__(self, locales, functions=None, use_isolating=True):
+        self.locales = locales
+        self._functions = functions or {}
+        self._use_isolating = use_isolating
+        self._messages = {}
+        self._terms = {}
+
+    def add_messages(self, source):
+        parser = FluentParser()
+        resource = parser.parse(source)
+        # TODO - warn if items get overwritten
+        for item in resource.body:
+            if isinstance(item, Message):
+                self._messages[item.id.name] = item
+            elif isinstance(item, Term):
+                self._terms[item.id.name] = item
+
+    def has_message(self, message_id):
+        return message_id in self._messages
+
+    def messages(self):
+        """
+        Returns iterable of (id, message) for the messages in this context
+        """
+        return six.iteritems(self._messages)

tests/test_context.py

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+from __future__ import absolute_import, unicode_literals
+
+import unittest
+
+from fluent.context import MessageContext
+
+from tests.syntax import dedent_ftl
+
+
+class TestMessageContext(unittest.TestCase):
+    def setUp(self):
+        self.ctx = MessageContext(['en-US'])
+
+    def test_add_messages(self):
+        self.ctx.add_messages(dedent_ftl("""
+            foo = Foo
+            bar = Bar
+            -baz = Baz
+        """))
+        self.assertIn('foo', self.ctx._messages)
+        self.assertIn('bar', self.ctx._messages)
+        self.assertNotIn('-baz', self.ctx._messages)
+        self.assertIn('-baz', self.ctx._terms)
+
+    def test_messages(self):
+        self.ctx.add_messages(dedent_ftl("""
+            foo = Foo
+            bar = Bar
+            -baz = Baz
+        """))
+        self.assertEqual(sorted([i for i, m in self.ctx.messages()]),
+                         ['bar', 'foo'])
+
+    def test_has_message(self):
+        self.ctx.add_messages(dedent_ftl("""
+            foo = Foo
+        """))
+
+        self.assertTrue(self.ctx.has_message('foo'))
+        self.assertFalse(self.ctx.has_message('bar'))