#!/usr/bin/env python3
#
# utils.py
"""
General utilities.
"""
#
# Copyright (c) 2020 Dominic Davis-Foster <dominic@davis-foster.co.uk>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301, USA.
#
# Based on ChemPy (https://github.com/bjodah/chempy)
# | Copyright (c) 2015-2018, Björn Dahlgren
# | All rights reserved.
# |
# | Redistribution and use in source and binary forms, with or without modification,
# | are permitted provided that the following conditions are met:
# |
# | Redistributions of source code must retain the above copyright notice, this
# | list of conditions and the following disclaimer.
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# | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#
# stdlib
import types
from collections import namedtuple, OrderedDict
from collections.abc import ItemsView, Mapping
from itertools import product
def identity(x):
return x
[docs]def defaultnamedtuple(typename, field_names, defaults=()):
"""
Generates a new subclass of tuple with default values.
Parameters
----------
typename : string
The name of the class.
field_names : str or iterable
An iterable of splitable string.
defaults : iterable
Default values for ``field_names``, counting ``[-len(defaults):]``.
Examples
--------
>>> Body = defaultnamedtuple('Body', 'x y z density', (1.0,))
>>> Body.__doc__
'Body(x, y, z, density)'
>>> b = Body(10, z=3, y=5)
>>> b._asdict() == dict(x=10, y=5, z=3, density=1.0)
True
Returns
-------
A new tuple subclass named ``typename``
"""
Tuple = namedtuple(typename, field_names)
Tuple.__new__.__defaults__ = (None,) * len(Tuple._fields)
if isinstance(defaults, Mapping):
Tuple.__new__.__defaults__ = tuple(Tuple(**defaults))
else:
nmissing = len(Tuple._fields) - len(defaults)
defaults = (None,) * nmissing + tuple(defaults)
Tuple.__new__.__defaults__ = tuple(Tuple(*defaults))
return Tuple