namespaces

5 files changed, 237 insertions, 0 deletions

diff --git a/bsfs/namespace/__init__.py b/bsfs/namespace/__init__.py
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+++ b/bsfs/namespace/__init__.py
@@ -0,0 +1,21 @@
+"""
+
+Part of the BlackStar filesystem (bsfs) module.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import typing
+
+# inner-module imports
+from . import predefined as ns
+from .namespace import ClosedNamespace, Namespace
+
+# exports
+__all__: typing.Sequence[str] = (
+    'ClosedNamespace',
+    'Namespace',
+    'ns',
+    )
+
+## EOF ##
diff --git a/bsfs/namespace/namespace.py b/bsfs/namespace/namespace.py
new file mode 100644
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+++ b/bsfs/namespace/namespace.py
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+"""
+
+Part of the BlackStar filesystem (bsfs) module.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import typing
+
+# bsfs imports
+from bsfs.utils import URI, typename
+
+# exports
+__all__: typing.Sequence[str] = (
+    'ClosedNamespace',
+    'Namespace',
+    )
+
+
+## code ##
+
+class Namespace():
+    """A namespace consists of a common prefix that is used in a set of URIs.
+
+    Note that the prefix must include the separator between
+    path and fragment (typically a '#' or a '/').
+    """
+
+    # namespace prefix.
+    prefix: URI
+
+    def __init__(self, prefix: URI):
+        self.prefix = URI(prefix)
+
+    def __eq__(self, other: typing.Any) -> bool:
+        return isinstance(other, type(self)) and self.prefix == other.prefix
+
+    def __hash__(self) -> int:
+        return hash((type(self), self.prefix))
+
+    def __str__(self) -> str:
+        return f'{typename(self)}({self.prefix})'
+
+    def __repr__(self) -> str:
+        return f'{typename(self)}({self.prefix})'
+
+    def __getattr__(self, fragment: str) -> URI:
+        """Return prefix + fragment."""
+        return URI(self.prefix + fragment)
+
+    def __getitem__(self, fragment: str) -> URI:
+        """Alias for getattr(self, fragment)."""
+        return self.__getattr__(fragment)
+
+
+class ClosedNamespace(Namespace):
+    """Namespace that covers a restricted set of URIs."""
+
+    # set of permissible fragments.
+    fragments: typing.Set[str]
+
+    def __init__(self, prefix: URI, *args: str):
+        super().__init__(prefix)
+        self.fragments = set(args)
+
+    def __eq__(self, other: typing.Any) -> bool:
+        return super().__eq__(other) and self.fragments == other.fragments
+
+    def __hash__(self) -> int:
+        return hash((type(self), self.prefix, tuple(sorted(self.fragments))))
+
+    def __getattr__(self, fragment: str) -> URI:
+        """Return prefix + fragment.
+        Raises a KeyError if the fragment is not allowed in this namespace.
+        """
+        if fragment not in self.fragments:
+            raise KeyError('fragment')
+        return super().__getattr__(fragment)
+
+## EOF ##
diff --git a/bsfs/namespace/predefined.py b/bsfs/namespace/predefined.py
new file mode 100644
index 0000000..21ca560
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+++ b/bsfs/namespace/predefined.py
@@ -0,0 +1,39 @@
+"""
+
+Part of the BlackStar filesystem (bsfs) module.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import typing
+
+# bsfs imports
+from bsfs.utils import URI
+
+# inner-module imports
+from . import namespace
+
+# essential bsfs namespaces
+bsfs: namespace.Namespace = namespace.Namespace(URI('http://bsfs.ai/schema/'))
+
+# additional bsfs namespaces
+bse: namespace.Namespace = namespace.Namespace(URI('http://bsfs.ai/schema/Entity#'))
+bsm: namespace.Namespace = namespace.Namespace(URI('http://bsfs.ai/schema/Meta#'))
+
+# generic namespaces
+rdf: namespace.Namespace = namespace.Namespace(URI('http://www.w3.org/1999/02/22-rdf-syntax-ns#'))
+rdfs: namespace.Namespace = namespace.Namespace(URI('http://www.w3.org/2000/01/rdf-schema#'))
+schema: namespace.Namespace = namespace.Namespace(URI('http://schema.org/'))
+xsd: namespace.Namespace = namespace.Namespace(URI('http://www.w3.org/2001/XMLSchema#'))
+
+__all__: typing.Sequence[str] = (
+    'bse',
+    'bsfs',
+    'bsm',
+    'rdf',
+    'rdfs',
+    'schema',
+    'xsd',
+    )
+
+## EOF ##
diff --git a/test/namespace/__init__.py b/test/namespace/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/namespace/__init__.py
diff --git a/test/namespace/test_namespace.py b/test/namespace/test_namespace.py
new file mode 100644
index 0000000..1ad53e3
--- /dev/null
+++ b/test/namespace/test_namespace.py
@@ -0,0 +1,97 @@
+"""
+
+Part of the tagit test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import unittest
+
+# objects to test
+from bsfs.namespace.namespace import Namespace, ClosedNamespace
+
+
+## code ##
+
+class TestNamespace(unittest.TestCase):
+    def test_essentials(self):
+        # string conversion
+        self.assertEqual(str(Namespace('http://example.org/')), 'Namespace(http://example.org/)')
+        self.assertEqual(str(Namespace('http://example.org#')), 'Namespace(http://example.org#)')
+        self.assertEqual(repr(Namespace('http://example.org/')), 'Namespace(http://example.org/)')
+        self.assertEqual(repr(Namespace('http://example.org#')), 'Namespace(http://example.org#)')
+        # comparison
+        class Foo(Namespace): pass
+        self.assertEqual(Namespace('http://example.org/'), Namespace('http://example.org/'))
+        self.assertNotEqual(Namespace('http://example.org/'), Foo('http://example.org/'))
+        self.assertNotEqual(Foo('http://example.org/'), Namespace('http://example.org/'))
+        self.assertNotEqual(Namespace('http://example.org/'), Namespace('http://example.org#'))
+        self.assertNotEqual(Namespace('http://example.org#'), Namespace('http://example.org/'))
+        # hashing
+        self.assertEqual(hash(Namespace('http://example.org/')), hash(Namespace('http://example.org/')))
+        self.assertNotEqual(hash(Namespace('http://example.org/')), hash(Foo('http://example.org/')))
+        self.assertNotEqual(hash(Foo('http://example.org/')), hash(Namespace('http://example.org/')))
+        self.assertNotEqual(hash(Namespace('http://example.org/')), hash(Namespace('http://example.org#')))
+        self.assertNotEqual(hash(Namespace('http://example.org#')), hash(Namespace('http://example.org/')))
+
+    def test_getattr(self):
+        self.assertEqual(Namespace('http://example.org/').foo, 'http://example.org/foo')
+        self.assertEqual(Namespace('http://example.org/').bar, 'http://example.org/bar')
+        self.assertEqual(Namespace('http://example.org/me#').foo, 'http://example.org/me#foo')
+        self.assertEqual(Namespace('http://example.org/me#').bar, 'http://example.org/me#bar')
+
+    def test_getitem(self):
+        self.assertEqual(Namespace('http://example.org/')['foo'], 'http://example.org/foo')
+        self.assertEqual(Namespace('http://example.org/')['bar'], 'http://example.org/bar')
+        self.assertEqual(Namespace('http://example.org/me#')['foo'], 'http://example.org/me#foo')
+        self.assertEqual(Namespace('http://example.org/me#')['bar'], 'http://example.org/me#bar')
+
+
+class TestClosedNamespace(unittest.TestCase):
+    def test_essentials(self):
+       # string conversion
+        self.assertEqual(str(ClosedNamespace('http://example.org/')), 'ClosedNamespace(http://example.org/)')
+        self.assertEqual(str(ClosedNamespace('http://example.org#')), 'ClosedNamespace(http://example.org#)')
+        self.assertEqual(repr(ClosedNamespace('http://example.org/')), 'ClosedNamespace(http://example.org/)')
+        self.assertEqual(repr(ClosedNamespace('http://example.org#')), 'ClosedNamespace(http://example.org#)')
+        # comparison
+        class Foo(ClosedNamespace): pass
+        self.assertEqual(ClosedNamespace('http://example.org/'), ClosedNamespace('http://example.org/'))
+        self.assertEqual(ClosedNamespace('http://example.org/', 'foo', 'bar'), ClosedNamespace('http://example.org/', 'foo', 'bar'))
+        self.assertNotEqual(ClosedNamespace('http://example.org/', 'foo'), ClosedNamespace('http://example.org/', 'bar'))
+        self.assertNotEqual(ClosedNamespace('http://example.org/'), Foo('http://example.org/'))
+        self.assertNotEqual(Foo('http://example.org/'), ClosedNamespace('http://example.org/'))
+        self.assertNotEqual(ClosedNamespace('http://example.org/'), ClosedNamespace('http://example.org#'))
+        self.assertNotEqual(ClosedNamespace('http://example.org#'), ClosedNamespace('http://example.org/'))
+        # hashing
+        self.assertEqual(hash(ClosedNamespace('http://example.org/')), hash(ClosedNamespace('http://example.org/')))
+        self.assertEqual(hash(ClosedNamespace('http://example.org/', 'foo', 'bar')), hash(ClosedNamespace('http://example.org/', 'foo', 'bar')))
+        self.assertNotEqual(hash(ClosedNamespace('http://example.org/', 'foo')), hash(ClosedNamespace('http://example.org/', 'bar')))
+        self.assertNotEqual(hash(ClosedNamespace('http://example.org/')), hash(Foo('http://example.org/')))
+        self.assertNotEqual(hash(Foo('http://example.org/')), hash(ClosedNamespace('http://example.org/')))
+        self.assertNotEqual(hash(ClosedNamespace('http://example.org/')), hash(ClosedNamespace('http://example.org#')))
+        self.assertNotEqual(hash(ClosedNamespace('http://example.org#')), hash(ClosedNamespace('http://example.org/')))
+
+    def test_getattr(self):
+        self.assertEqual(ClosedNamespace('http://example.org/', 'foo', 'bar').foo, 'http://example.org/foo')
+        self.assertEqual(ClosedNamespace('http://example.org/', 'bar', 'bar').bar, 'http://example.org/bar')
+        self.assertEqual(ClosedNamespace('http://example.org/me#', 'foo', 'bar').foo, 'http://example.org/me#foo')
+        self.assertEqual(ClosedNamespace('http://example.org/me#', 'foo', 'bar').bar, 'http://example.org/me#bar')
+        self.assertRaises(KeyError, getattr, ClosedNamespace('http://example.org/', 'bar', 'bar'), 'foobar')
+        self.assertRaises(KeyError, getattr, ClosedNamespace('http://example.org#', 'bar', 'bar'), 'foobar')
+
+    def test_getitem(self):
+        self.assertEqual(ClosedNamespace('http://example.org/', 'foo', 'bar')['foo'], 'http://example.org/foo')
+        self.assertEqual(ClosedNamespace('http://example.org/', 'foo', 'bar')['bar'], 'http://example.org/bar')
+        self.assertEqual(ClosedNamespace('http://example.org/me#', 'foo', 'bar')['foo'], 'http://example.org/me#foo')
+        self.assertEqual(ClosedNamespace('http://example.org/me#', 'foo', 'bar')['bar'], 'http://example.org/me#bar')
+        self.assertRaises(KeyError, ClosedNamespace('http://example.org/', 'bar', 'bar').__getitem__, 'foobar')
+        self.assertRaises(KeyError, ClosedNamespace('http://example.org#', 'bar', 'bar').__getitem__, 'foobar')
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##