Source code for pint.facets.system.definitions
"""
pint.facets.systems.definitions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:copyright: 2022 by Pint Authors, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
from __future__ import annotations
from collections.abc import Iterable
from dataclasses import dataclass
from ... import errors
from ...compat import Self
@dataclass(frozen=True)
class BaseUnitRule:
"""A rule to define a base unit within a system."""
#: name of the unit to become base unit
#: (must exist in the registry)
new_unit_name: str
#: name of the unit to be kicked out to make room for the new base uni
#: If None, the current base unit with the same dimensionality will be used
old_unit_name: str | None = None
# Instead of defining __post_init__ here,
# it will be added to the container class
# so that the name and a meaningfull class
# could be used.
[docs]
@dataclass(frozen=True)
class SystemDefinition(errors.WithDefErr):
"""Definition of a System."""
#: name of the system
name: str
#: unit groups that will be included within the system
using_group_names: tuple[str, ...]
#: rules to define new base unit within the system.
rules: tuple[BaseUnitRule, ...]
@classmethod
def from_lines(
cls: type[Self], lines: Iterable[str], non_int_type: type
) -> Self | None:
# TODO: this is to keep it backwards compatible
# TODO: check when is None returned.
from ...delegates import ParserConfig, txt_defparser
cfg = ParserConfig(non_int_type)
parser = txt_defparser.DefParser(cfg, None)
pp = parser.parse_string("\n".join(lines) + "\n@end")
for definition in parser.iter_parsed_project(pp):
if isinstance(definition, cls):
return definition
@property
def unit_replacements(self) -> tuple[tuple[str, str | None], ...]:
# TODO: check if None can be dropped.
return tuple((el.new_unit_name, el.old_unit_name) for el in self.rules)
def __post_init__(self):
if not errors.is_valid_system_name(self.name):
raise self.def_err(errors.MSG_INVALID_SYSTEM_NAME)
for k in self.using_group_names:
if not errors.is_valid_group_name(k):
raise self.def_err(
f"refers to '{k}' that " + errors.MSG_INVALID_GROUP_NAME
)
for ndx, rule in enumerate(self.rules, 1):
if not errors.is_valid_unit_name(rule.new_unit_name):
raise self.def_err(
f"rule #{ndx} refers to '{rule.new_unit_name}' that "
+ errors.MSG_INVALID_UNIT_NAME
)
if rule.old_unit_name and not errors.is_valid_unit_name(rule.old_unit_name):
raise self.def_err(
f"rule #{ndx} refers to '{rule.old_unit_name}' that "
+ errors.MSG_INVALID_UNIT_NAME
)