Source code for pint.facets.system.definitions


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

from __future__ import annotations

import typing as ty
from dataclasses import dataclass

from ... import errors

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: ty.Optional[str] = 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: ty.Tuple[str, ...] #: rules to define new base unit within the system. rules: ty.Tuple[BaseUnitRule, ...] @classmethod def from_lines(cls, lines, non_int_type): # TODO: this is to keep it backwards compatible 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) -> ty.Tuple[ty.Tuple[str, str], ...]: 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( 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 )