Source code for lz.right

import functools as _functools
import itertools as _itertools
import typing as _t

from . import left as _left
from ._core.right import Applier as _Applier
from .functional import (compose as _compose,
                         flip as _flip)
from .iterating import expand as _expand
from .reversal import reverse as _reverse

_T1 = _t.TypeVar('_T1')
_T2 = _t.TypeVar('_T2')


[docs]def accumulator( _function: _t.Callable[[_T1, _T2], _T2], _initial: _T2 ) -> _t.Callable[[_t.Iterable[_T1]], _t.Iterable[_t.Iterable[_T2]]]: """ Returns function that yields cumulative results of given binary function starting from given initial object in direction from right to left. >>> def to_next_fraction(partial_denominator: int, ... reciprocal: float) -> float: ... return partial_denominator + 1 / reciprocal >>> to_simple_continued_fractions = accumulator(to_next_fraction, 1) >>> from itertools import repeat >>> [round(fraction, 4) ... for fraction in to_simple_continued_fractions(list(repeat(1, 10)))] [1, 2.0, 1.5, 1.6667, 1.6, 1.625, 1.6154, 1.619, 1.6176, 1.6182, 1.618] """ return _t.cast(_t.Callable[[_t.Iterable[_T1]], _t.Iterable[_t.Iterable[_T2]]], _compose(_left.accumulator(_flip(_function), _initial), _reverse))
[docs]def accumulate(_function: _t.Callable[[_T1, _T2], _T2], _initial: _T2, _iterable: _t.Iterable[_T1]) -> _t.Iterable[_T2]: """ Yields cumulative results of given binary function starting from given initial object in direction from right to left. >>> def to_next_fraction(partial_denominator: int, ... reciprocal: float) -> float: ... return partial_denominator + 1 / reciprocal >>> from itertools import repeat >>> [round(fraction, 4) ... for fraction in accumulate(to_next_fraction, 1, list(repeat(1, 10)))] [1, 2.0, 1.5, 1.6667, 1.6, 1.625, 1.6154, 1.619, 1.6176, 1.6182, 1.618] """ return _left.accumulate(_flip(_function), _initial, _reverse(_iterable))
[docs]def attacher(_value: _T1) -> _t.Callable[[_t.Iterable[_T1]], _t.Iterable[_T1]]: """ Returns function that appends given object to iterable. >>> attach_hundred = attacher(100) >>> list(attach_hundred(range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 100] """ return _t.cast(_t.Callable[[_t.Iterable[_T1]], _t.Iterable[_T1]], _Applier(attach, _value))
[docs]@_functools.singledispatch def attach(_iterable: _t.Iterable[_T1], _value: _T1) -> _t.Iterable[_T1]: """ Appends given object to the iterable. """ yield from _itertools.chain(_iterable, _expand(_value))
@attach.register(list) def _(_iterable: _t.List[_T1], _value: _T1) -> _t.List[_T1]: """ Appends given object to the list. """ return _iterable + [_value] @attach.register(tuple) def _(_iterable: _t.Tuple[_T1, ...], _value: _T1) -> _t.Tuple[_T1, ...]: """ Appends given object to the tuple. """ return _iterable + (_value,)
[docs]def folder(_function: _t.Callable[[_T1, _T2], _T2], _initial: _T2) -> _t.Callable[[_t.Iterable[_T1]], _T2]: """ Returns function that cumulatively applies given binary function starting from given initial object in direction from right to left. >>> to_sum_evaluation_order = folder('({} + {})'.format, 0) >>> to_sum_evaluation_order(range(1, 10)) '(1 + (2 + (3 + (4 + (5 + (6 + (7 + (8 + (9 + 0)))))))))' """ left_folder = _left.folder(_flip(_function), _initial) return _t.cast(_t.Callable[[_t.Iterable[_T1]], _T2], _compose(left_folder, _reverse))
[docs]def fold(_function: _t.Callable[[_T2, _T1], _T2], _initial: _T2, _iterable: _t.Iterable[_T1]) -> _T2: """ Cumulatively applies given binary function starting from given initial object in direction from left to right. >>> fold('({} + {})'.format, 0, range(1, 10)) '(1 + (2 + (3 + (4 + (5 + (6 + (7 + (8 + (9 + 0)))))))))' """ return _functools.reduce(_flip(_function), _reverse(_iterable), _initial)
[docs]def applier(_function: _t.Callable[..., _T2], *args: _t.Any, **kwargs: _t.Any) -> _t.Callable[..., _T2]: """ Returns function that behaves like given function with given arguments partially applied. Given positional arguments will be added to the right end. >>> square = applier(pow, 2) >>> square(10) 100 """ return _Applier(_function, *args, **kwargs)