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# -*- coding: utf-8 -*- 

 

u'''Basic definitions, decorators and functions. 

''' 

from pygeodesy.errors import _AttributeError, _IsnotError, \ 

_TypesError, _ValueError 

from pygeodesy.interns import NEG0, NN, _COMMA_SPACE_, _DOT_, \ 

joined_, _UNDERSCORE_, _utf_8_, \ 

_version_, _0_0 

from pygeodesy.lazily import _ALL_LAZY, _FOR_DOCS 

 

from copy import copy as _copy, deepcopy as _deepcopy 

from inspect import isclass as _isclass 

from math import copysign, isinf, isnan 

 

__all__ = _ALL_LAZY.basics 

__version__ = '20.10.10' 

 

try: # Luciano Ramalho, "Fluent Python", page 395, O'Reilly, 2016 

from numbers import Integral as _Ints # int objects 

except ImportError: # PYCHOK no cover 

try: 

_Ints = int, long # int objects (C{tuple}) 

except NameError: # Python 3+ 

_Ints = int, # int objects (C{tuple}) 

 

try: # similarly ... 

from numbers import Real as _Scalars # scalar objects 

except ImportError: # PYCHOK no cover 

try: 

_Scalars = int, long, float # scalar objects (C{tuple}) 

except NameError: 

_Scalars = int, float # scalar objects (C{tuple}) 

 

try: 

try: # use C{from collections.abc import ...} in Python 3.9+ 

from collections.abc import Sequence as _Sequence # imported by .points 

except ImportError: # no .abc in Python 2.7- 

from collections import Sequence as _Sequence # imported by .points 

if isinstance([], _Sequence) and isinstance((), _Sequence): 

# and isinstance(range(1), _Sequence): 

_Seqs = _Sequence 

else: 

raise ImportError # _AssertionError 

except ImportError: # PYCHOK no cover 

_Sequence = tuple # immutable for .points._Basequence 

_Seqs = list, _Sequence # , range for function len2 below 

 

try: 

_Bytes = unicode, bytearray # PYCHOK expected 

_Strs = basestring, str 

except NameError: # Python 3+ 

_Bytes = bytes, bytearray 

_Strs = str, 

 

 

def _bkwds(inst, Error=AttributeError, **name_value_pairs): # in .frechet, .hausdorff, .heights 

'''(INTERNAL) Set applicable C{bool} properties/attributes. 

''' 

for n, v in name_value_pairs.items(): 

b = getattr(inst, n, None) 

if b is None: # invalid bool attr 

t = n, v, inst.__class__.__name__ # XXX .classname 

raise Error('not applicable: %s=%r for %s' % t) 

if v in (False, True) and v != b: 

setattr(inst, _UNDERSCORE_ + n, v) 

 

 

def clips(bstr, limit=50, white=NN): 

'''Clip a string to the given length limit. 

 

@arg bstr: String (C{bytes} or C{str}). 

@kwarg limit: Length limit (C{int}). 

@kwarg white: Optionally, replace all whitespace (C{str}). 

 

@return: The clipped or unclipped B{C{bstr}}. 

''' 

if len(bstr) > limit > 8: 

h = limit // 2 

bstr = bstr[:h] + type(bstr)('....') + bstr[-h:] 

if white: # replace whitespace 

bstr = type(bstr)(white).join(bstr.split()) 

return bstr 

 

 

def halfs2(str2): 

'''Split a string in 2 halfs. 

 

@arg str2: String to split (C{str}). 

 

@return: 2-Tuple (_1st, _2nd) half (C{str}). 

 

@raise ValueError: Zero or odd C{len}(B{C{str2}}). 

''' 

h, r = divmod(len(str2), 2) 

if r or not h: 

raise _ValueError(str2=str2, txt='odd') 

return str2[:h], str2[h:] 

 

 

if _FOR_DOCS: # XXX avoid epidoc Python 2.7 error 

def isclass(obj): 

'''Return C{True} if B{C{obj}} is a C{class}. 

 

@see: Python's C{inspect.isclass}. 

''' 

return _isclass(obj) 

else: 

isclass = _isclass 

 

 

try: 

from math import isfinite # new in Python 3+ 

except ImportError: 

 

def isfinite(obj): 

'''Check for C{Inf} and C{NaN} values. 

 

@arg obj: Value (C{scalar}). 

 

@return: C{False} if B{C{obj}} is C{INF} or C{NAN}, 

C{True} otherwise. 

 

@raise TypeError: Non-scalar B{C{obj}}. 

''' 

if not isscalar(obj): 

raise _IsnotError(isscalar.__name__, obj=obj) 

return not (isinf(obj) or isnan(obj)) 

 

 

try: 

isidentifier = str.isidentifier # Python 3, must be str 

except AttributeError: # Python 2- 

 

def isidentifier(obj): 

'''Return C{True} if B{C{obj}} is a valid Python identifier. 

''' 

return True if (obj and obj.replace(_UNDERSCORE_, NN).isalnum() 

and not obj[:1].isdigit()) else False 

 

 

def isint(obj, both=False): 

'''Check for C{int} type or an integer C{float} value. 

 

@arg obj: The object (any C{type}). 

@kwarg both: Optionally, check C{float} type and value (C{bool}). 

 

@return: C{True} if B{C{obj}} is C{int} or an integer 

C{float}, C{False} otherwise. 

''' 

if both and isinstance(obj, float): # NOT _Scalars! 

try: 

return obj.is_integer() 

except AttributeError: # PYCHOK no cover 

return False # XXX float(int(obj)) == obj? 

return isinstance(obj, _Ints) 

 

 

try: 

from keyword import iskeyword # Python 2.7+ 

except ImportError: 

 

def iskeyword(unused): 

'''Not Implemented. Return C{False}, always. 

''' 

return False 

 

 

def isneg0(obj): 

'''Check for L{NEG0}, negative 0.0. 

 

@arg obj: Value (C{scalar}). 

 

@return: C{True} if B{C{obj}} is C{NEG0} or -0.0, 

C{False} otherwise. 

''' 

return obj in (_0_0, NEG0) and copysign(1, obj) < 0 

# and str(obj).rstrip(_0_) == '-0.' 

 

 

def isscalar(obj): 

'''Check for scalar types. 

 

@arg obj: The object (any C{type}). 

 

@return: C{True} if B{C{obj}} is C{scalar}, C{False} otherwise. 

''' 

return isinstance(obj, _Scalars) 

 

 

def issequence(obj, *excluded): 

'''Check for sequence types. 

 

@arg obj: The object (any C{type}). 

@arg excluded: Optional exclusions (C{type}). 

 

@note: Excluding C{tuple} implies excluding C{namedtuple}. 

 

@return: C{True} if B{C{obj}} is a sequence, C{False} otherwise. 

''' 

return False if (excluded and isinstance(obj, excluded)) else \ 

isinstance(obj, _Seqs) 

 

 

def isstr(obj): 

'''Check for string types. 

 

@arg obj: The object (any C{type}). 

 

@return: C{True} if B{C{obj}} is C{str}, C{False} otherwise. 

''' 

return isinstance(obj, _Strs) 

 

 

def issubclassof(Sub, Super): 

'''Check whether a class is a sub-class of a super class. 

 

@arg Sub: The sub-class (C{class}). 

@arg Super: The super class (C{class}). 

 

@return: C{True} if B{C{Sub}} is a sub-class of B{C{Super}}, 

C{False} otherwise (C{bool}). 

''' 

return isclass(Sub) and isclass(Super) and issubclass(Sub, Super) 

 

 

def len2(items): 

'''Make built-in function L{len} work for generators, iterators, 

etc. since those can only be started exactly once. 

 

@arg items: Generator, iterator, list, range, tuple, etc. 

 

@return: 2-Tuple C{(n, items)} of the number of items (C{int}) 

and the items (C{list} or C{tuple}). 

''' 

if not isinstance(items, _Seqs): # NOT hasattr(items, '__len__'): 

items = list(items) 

return len(items), items 

 

 

def map1(func, *xs): # XXX map_ 

'''Apply each argument to a single-argument function and 

return a C{tuple} of results. 

 

@arg func: Function to apply (C{callable}). 

@arg xs: Arguments to apply (C{any positional}). 

 

@return: Function results (C{tuple}). 

''' 

return tuple(map(func, xs)) # note, NO *xs 

 

 

def map2(func, *xs): 

'''Apply arguments to a function and return a C{tuple} of results. 

 

Unlike Python 2's built-in L{map}, Python 3+ L{map} returns a 

L{map} object, an iterator-like object which generates the 

results only once. Converting the L{map} object to a tuple 

maintains Python 2 behavior. 

 

@arg func: Function to apply (C{callable}). 

@arg xs: Arguments to apply (C{list, tuple, ...}). 

 

@return: Function results (C{tuple}). 

''' 

return tuple(map(func, *xs)) # note, *xs 

 

 

def property_doc_(doc): 

'''Decorator for a property with documentation. 

 

@arg doc: The property documentation (C{str}). 

 

@example: 

 

>>> @property_doc_("documentation text.") 

>>> def name(self): 

>>> ... 

>>> 

>>> @name.setter 

>>> def name(self, value): 

>>> ... 

''' 

# See Luciano Ramalho, "Fluent Python", page 212ff, O'Reilly, 2016, 

# "Parameterized Decorators", especially Example 7-23. Also, see 

# <https://Python-3-Patterns-Idioms-Test.ReadTheDocs.io/en/latest/PythonDecorators.html> 

 

def _property(method): 

'''(INTERNAL) Return C{method} as documented C{property.getter}. 

''' 

t = 'get and set' if doc.startswith(' ') else NN 

return property(method, None, None, 'Property to ' + t + doc) 

 

return _property 

 

 

class property_RO(property): 

# No __doc__ on purpose 

 

def __init__(self, method): # PYCHOK signature 

'''New immutable, read-only L{property_RO} to be used as C{decorator}. 

 

@arg method: The callable being decorated as C{property.getter}. 

 

@note: Like standard Python C{property} without a C{property.setter} 

and with a more descriptive error message when set. 

''' 

if _FOR_DOCS and method.__doc__: 

self.__doc__ = method.__doc__ 

self.name = method.__name__ # == self.fget.__name__ 

 

# U{Descriptor HowTo Guide<https://docs.Python.org/3/howto/descriptor.html>} 

def immutable(inst, value): 

'''Throws an C{AttributeError}, always. 

''' 

t = immutable.__name__, inst, method.__name__, value 

raise _AttributeError('%s property: %r.%s = %r' % t) 

 

property.__init__(self, method, immutable, None, method.__doc__ or 'N/A') 

 

 

# def property_RO(method): # OBSOLETE 

# '''An immutable property (C{Read Only}). 

# 

# @arg method: The callable to be decorated as C{property.getter}. 

# 

# @note: Like standard Python C{property} without a C{property.setter}, 

# but with a more descriptive error message when set. 

# ''' 

# def Read_Only(inst, value): 

# '''Throws an C{AttributeError}, always. 

# ''' 

# t = Read_Only.__name__, inst, method.__name__, value 

# raise AttributeError('%s property: %r.%s = %r' % t) 

# 

# return property(method, Read_Only, None, method.__doc__ or 'N/A') 

 

 

def ub2str(ub): 

'''Convert C{unicode} or C{bytes} to C{str}. 

''' 

if isinstance(ub, _Bytes): 

ub = str(ub.decode(_utf_8_)) 

return ub 

 

 

def _xattrs(insto, other, *attrs): 

'''(INTERNAL) Copy attribute values from B{C{other}} to B{C{insto}}. 

 

@arg insto: Object to copy attribute values to (any C{type}). 

@arg other: Object to copy attribute values from (any C{type}). 

@arg attrs: One or more attribute names (C{str}s). 

 

@return: Object B{C{insto}}, updated. 

 

@raise AttributeError: An B{C{attrs}} doesn't exist 

or is not settable. 

''' 

def _getattr(o, a): 

if hasattr(o, a): 

return getattr(o, a) 

raise _AttributeError('.%s' % (a,), o) 

 

for a in attrs: 

s = _getattr(other, a) 

g = _getattr(insto, a) 

if (g is None and s is not None) or g != s: 

setattr(insto, a, s) # not settable? 

return insto 

 

 

def _xcopy(inst, deep=False): 

'''(INTERNAL) Copy an object, shallow or deep. 

 

@arg inst: The object to copy (any C{type}). 

@kwarg deep: If C{True} make a deep, otherwise 

a shallow copy (C{bool}). 

 

@return: The copy of B{C{inst}}. 

''' 

return _deepcopy(inst) if deep else _copy(inst) 

 

 

def _xinstanceof(*Types, **name_value_pairs): 

'''(INTERNAL) Check C{Types} of all C{name=value} pairs. 

 

@arg Types: One or more classes or types (C{class}). 

@kwarg name_value_pairs: One or more B{C{name=value}} pairs 

with the C{value} to be checked. 

 

@raise TypeError: At least one of the B{C{name_value_pairs}} 

is not any of the B{C{Types}}. 

''' 

for n, v in name_value_pairs.items(): 

if not isinstance(v, Types): 

raise _TypesError(n, v, *Types) 

 

 

def _xkwds(kwds, **dflts): 

'''(INTERNAL) Override C{dflts} with C{kwds}. 

''' 

d = dflts 

if kwds: 

d = _copy(d) 

d.update(kwds) 

return d 

 

 

def _xnumpy(where, *required): 

'''(INTERNAL) Import C{numpy} and check required version 

''' 

import numpy 

return _xversion(numpy, where, *required) 

 

 

def _xscipy(where, *required): 

'''(INTERNAL) Import C{scipy} and check required version 

''' 

import scipy 

return _xversion(scipy, where, *required) 

 

 

def _xsubclassof(Class, **name_value_pairs): 

'''(INTERNAL) Check super C{Class} of all C{name=value} pairs. 

 

@arg Class: A class or type (C{class}). 

@kwarg name_value_pairs: One or more B{C{name=value}} pairs 

with the C{value} to be checked. 

 

@raise TypeError: At least one of the B{C{name_value_pairs}} 

is not a sub-class of B{C{Class}}. 

''' 

for n, v in name_value_pairs.items(): 

if not issubclassof(v, Class): 

raise _TypesError(n, v, Class) 

 

 

def _xversion(package, where, *required): # in .karney 

'''(INTERNAL) Check the C{package} version vs B{C{required}}. 

''' 

t = map2(int, package.__version__.split(_DOT_)[:2]) 

if t < required: 

from pygeodesy.named import modulename as mn 

t = joined_(package.__name__, _version_, 

_DOT_.join(map2(str, t)), 'below', 

_DOT_.join(map2(str, required)), 

'required', 'by', mn(where, True)) 

raise ImportError(t) 

return package 

 

 

def _xzipairs(lefts, rights, sep=_COMMA_SPACE_, fmt=NN, pair='%s:%s'): 

'''(INTERNAL) Zip C{lefts} and C{rights} into a C{str}. 

''' 

t = sep.join(pair % t for t in zip(lefts, rights)) 

if fmt: 

t = fmt % (t,) 

return t 

 

# **) MIT License 

# 

# Copyright (C) 2016-2020 -- mrJean1 at Gmail -- All Rights Reserved. 

# 

# 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.