Source code for


    :copyright: 2022 by Pint Authors, see AUTHORS for more details.
    :license: BSD, see LICENSE for more details.

from __future__ import annotations

from typing import TYPE_CHECKING, Dict, FrozenSet

from ... import errors

    from pint import Unit

from ...util import build_dependent_class, create_class_with_registry
from ..plain import PlainRegistry, UnitDefinition
from .definitions import GroupDefinition
from .objects import Group

[docs]class GroupRegistry(PlainRegistry): """Handle of Groups. Group units Capabilities: - Register groups. - Parse @group directive. """ # TODO: Change this to Group: Group to specify class # and use introspection to get system class as a way # to enjoy typing goodies _group_class = Group def __init__(self, **kwargs): super().__init__(**kwargs) #: Map group name to group. #: :type: dict[ str | Group] self._groups: Dict[str, Group] = {} self._groups["root"] = self.Group("root") def __init_subclass__(cls, **kwargs): super().__init_subclass__() cls.Group = build_dependent_class(cls, "Group", "_group_class") def _init_dynamic_classes(self) -> None: """Generate subclasses on the fly and attach them to self""" super()._init_dynamic_classes() self.Group = create_class_with_registry(self, self.Group) def _after_init(self) -> None: """Invoked at the end of ``__init__``. - Create default group and add all orphan units to it - Set default system """ super()._after_init() #: Copy units not defined in any group to the default group if "group" in self._defaults: grp = self.get_group(self._defaults["group"], True) group_units = frozenset( [ member for group in self._groups.values() if != "root" for member in group.members ] ) all_units = self.get_group("root", False).members grp.add_units(*(all_units - group_units)) def _register_definition_adders(self) -> None: super()._register_definition_adders() self._register_adder(GroupDefinition, self._add_group) def _add_unit(self, definition: UnitDefinition): super()._add_unit(definition) # TODO: delta units are missing self.get_group("root").add_units( def _add_group(self, gd: GroupDefinition): if in self._groups: raise ValueError(f"Group {} already present in registry") try: # As a Group is a SharedRegistryObject # it adds itself to the registry. self.Group.from_definition(gd) except KeyError as e: raise errors.DefinitionSyntaxError(f"unknown dimension {e} in context")
[docs] def get_group(self, name: str, create_if_needed: bool = True) -> Group: """Return a Group. Parameters ---------- name : str Name of the group to be create_if_needed : bool If True, create a group if not found. If False, raise an Exception. (Default value = True) Returns ------- Group Group """ if name in self._groups: return self._groups[name] if not create_if_needed: raise ValueError("Unknown group %s" % name) return self.Group(name)
def _get_compatible_units(self, input_units, group) -> FrozenSet["Unit"]: ret = super()._get_compatible_units(input_units, group) if not group: return ret if group in self._groups: members = self._groups[group].members else: raise ValueError("Unknown Group with name '%s'" % group) return frozenset(ret & members)