"""
Tag Interface
---------------
.. ``normalize_tags`` undocumented for now. (Not ready to commit.)
.. autofunction:: check_tag_uniqueness
.. autoclass:: Taggable
.. autoclass:: Tag
.. autoclass:: UniqueTag
Supporting Functionality
------------------------
.. autoclass:: DottedName
.. autoclass:: NonUniqueTagError
Internal stuff that is only here because the documentation tool wants it
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. class:: T_co
A covariant type variable used in, e.g. :meth:`Taggable.copy`.
"""
from dataclasses import dataclass
from typing import Tuple, Set, Any, FrozenSet, Union, Iterable, TypeVar
from pytools import memoize
__copyright__ = """
Copyright (C) 2020 Andreas Klöckner
Copyright (C) 2020 Matt Wala
Copyright (C) 2020 Xiaoyu Wei
Copyright (C) 2020 Nicholas Christensen
"""
__license__ = """
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
# {{{ dotted name
[docs]class DottedName:
"""
.. attribute:: name_parts
A tuple of strings, each of which is a valid
Python identifier. No name part may start with
a double underscore.
The name (at least morally) exists in the
name space defined by the Python module system.
It need not necessarily identify an importable
object.
.. automethod:: from_class
"""
def __init__(self, name_parts: Tuple[str, ...]):
if len(name_parts) == 0:
raise ValueError("empty name parts")
for p in name_parts:
if not p.isidentifier():
raise ValueError(f"{p} is not a Python identifier")
self.name_parts = name_parts
[docs] @classmethod
def from_class(cls, argcls: Any) -> "DottedName":
name_parts = tuple(
[str(part) for part in argcls.__module__.split(".")]
+ [str(argcls.__name__)])
if not all(not npart.startswith("__") for npart in name_parts):
raise ValueError(f"some name parts of {'.'.join(name_parts)} "
"start with double underscores")
return cls(name_parts)
# }}}
# {{{ tag
tag_dataclass = dataclass(init=True, eq=True, frozen=True, repr=True)
[docs]@tag_dataclass
class Tag:
"""
Generic metadata, applied to, among other things,
pytato Arrays.
.. attribute:: tag_name
A fully qualified :class:`DottedName` that reflects
the class name of the tag.
Instances of this type must be immutable, hashable,
picklable, and have a reasonably concise :meth:`__repr__`
of the form ``dotted.name(attr1=value1, attr2=value2)``.
Positional arguments are not allowed.
.. automethod:: __repr__
"""
@property
def tag_name(self) -> DottedName:
return DottedName.from_class(type(self))
def update_persistent_hash(self, key_hash, key_builder):
key_builder.rec(key_hash,
(self.__class__.__module__, self.__class__.__qualname__))
from dataclasses import fields
# Fields are ordered consistently, so ordered hashing is OK.
#
# No need to dispatch to superclass: fields() automatically gives us
# fields from the entire class hierarchy.
for f in fields(self):
key_builder.rec(key_hash, getattr(self, f.name))
# }}}
# {{{ unique tag
[docs]class UniqueTag(Tag):
"""
A superclass for tags that are unique on each :class:`Taggable`.
Each instance of :class:`Taggable` may have no more than one
instance of each subclass of :class:`UniqueTag` in its
set of `tags`. Multiple `UniqueTag` instances of
different (immediate) subclasses are allowed.
"""
pass
# }}}
TagsType = FrozenSet[Tag]
TagOrIterableType = Union[Iterable[Tag], Tag, None]
T_co = TypeVar("T_co", bound="Taggable")
# {{{ UniqueTag rules checking
@memoize
def _immediate_unique_tag_descendants(cls):
if UniqueTag in cls.__bases__:
return frozenset([cls])
else:
result = frozenset()
for base in cls.__bases__:
result = result | _immediate_unique_tag_descendants(base)
return result
[docs]class NonUniqueTagError(ValueError):
"""
Raised when a :class:`Taggable` object is instantiated with more
than one :class:`UniqueTag` instances of the same subclass in
its set of tags.
"""
pass
[docs]def check_tag_uniqueness(tags: TagsType):
"""Ensure that *tags* obeys the rules set forth in :class:`UniqueTag`.
If not, raise :exc:`NonUniqueTagError`. If any *tags* are not
subclasses of :class:`Tag`, a :exc:`TypeError` will be raised.
:returns: *tags*
"""
unique_tag_descendants: Set[Tag] = set()
for tag in tags:
if not isinstance(tag, Tag):
raise TypeError(f"'{tag}' is not an instance of pytools.tag.Tag")
tag_unique_tag_descendants = _immediate_unique_tag_descendants(
type(tag))
intersection = unique_tag_descendants & tag_unique_tag_descendants
if intersection:
raise NonUniqueTagError("Multiple tags are direct subclasses of "
"the following UniqueTag(s): "
f"{', '.join(d.__name__ for d in intersection)}")
else:
unique_tag_descendants.update(tag_unique_tag_descendants)
return tags
# }}}
def normalize_tags(tags: TagOrIterableType) -> TagsType:
if isinstance(tags, Tag):
tags = frozenset([tags])
elif tags is None:
tags = frozenset()
else:
tags = frozenset(tags)
return tags
# {{{ taggable
[docs]class Taggable:
"""
Parent class for objects with a `tags` attribute.
.. attribute:: tags
A :class:`frozenset` of :class:`Tag` instances
.. automethod:: __init__
.. automethod:: copy
.. automethod:: tagged
.. automethod:: without_tags
.. versionadded:: 2021.1
"""
# ReST references in docstrings must be fully qualified, as docstrings may
# be inherited and appear in different contexts.
[docs] def __init__(self, tags: TagsType = frozenset()):
"""
Constructor for all objects that possess a `tags` attribute.
:arg tags: a :class:`frozenset` of :class:`~pytools.tag.Tag` objects.
Tags can be modified via the :meth:`~pytools.tag.Taggable.tagged` and
:meth:`~pytools.tag.Taggable.without_tags` routines. Input checking
of *tags* should be performed before creating a
:class:`~pytools.tag.Taggable` instance, using
:func:`~pytools.tag.check_tag_uniqueness`.
"""
self.tags = tags
[docs] def copy(self: T_co, **kwargs: Any) -> T_co:
"""
Returns of copy of *self* with the specified tags. This method
should be overridden by subclasses.
"""
raise NotImplementedError("The copy function is not implemented.")
[docs] def tagged(self: T_co, tags: TagOrIterableType) -> T_co:
"""
Return a copy of *self* with the specified
tag or tags unioned. If *tags* is a :class:`pytools.tag.UniqueTag`
and other tags of this type are already present, an error is raised
Assumes `self.copy(tags=<NEW VALUE>)` is implemented.
:arg tags: An instance of :class:`~pytools.tag.Tag` or
an iterable with instances therein.
"""
return self.copy(
tags=check_tag_uniqueness(normalize_tags(tags) | self.tags))
# }}}
# vim: foldmethod=marker