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# -*- coding: UTF-8 -*-
# Copyright 2014 Red Hat, Inc.
# Part of clufter project
# Licensed under GPLv2+ (a copy included | http://gnu.org/licenses/gpl-2.0.txt)
"""Various functional-paradigm helpers"""
__author__ = "Jan Pokorný <jpokorny @at@ Red Hat .dot. com>"
from .utils import tuplist
apply_preserving_depth = \
lambda action: \
lambda item: \
type(item)(apply_preserving_depth(action)(i) for i in item) \
if tuplist(item) else action(item)
apply_aggregation_preserving_depth = \
lambda agg_fn: \
lambda item: \
agg_fn(type(item)(apply_aggregation_preserving_depth(agg_fn)(i)
for i in item)) \
if tuplist(item) else item
apply_aggregation_preserving_passing_depth = \
lambda agg_fn, d=0: \
lambda item: \
agg_fn(type(item)(
apply_aggregation_preserving_passing_depth(agg_fn, d+1)(i)
for i in item),
d+1
) \
if tuplist(item) else item
# name comes from Haskell
# note: always returns list even for input tuple
# note: when returning from recursion, should always observe scalar or list(?)
apply_intercalate = apply_aggregation_preserving_depth(
lambda i:
reduce(lambda a, b: a + (b if isinstance(b, list) else [b]),
i, [])
)
bifilter = \
lambda fnc, seq: \
reduce(lambda acc, x: acc[int(not fnc(x))].append(x) or acc,
seq, ([], []))
# Given the partitioning function, do the recursive refinement in a way
# the parts reaching the bottom line in more steps are continually "shaked"
# towards the end (with a stable relative order, though).
# Default partitioning function just distinguishes between tuples/lists
# and other values (presumably scalars) so when passed a tuple/list encoding
# a graph (tree/forest) in a DFS manner using unrestricted nesting, it will
# return serialized BFS walk of the same.
# NOTE if there are scalars already at the start-level depth, use
# `tail_shake_safe` (not that it provides much more guarantee :-p)
tailshake = \
lambda src, partitioner=(lambda x: not tuplist(x)): \
reduce(lambda a, b: a + (tailshake(b, partitioner) if b else b),
reduce(lambda a, b: (a[0] + b[0], a[1] + b[1]),
tuple(bifilter(partitioner, i) if tuplist(i) else (i, [])
for i in src), ([], [])))
tailshake_safe = \
lambda src, partitioner=(lambda x: not tuplist(x)): \
tailshake(src if all(tuplist(i) for i in src) else (src, ),
partitioner)
zipped_outlier = type('zipped_outlier', (tuple, ), {})
zip_empty = type('zip_filler', (str, ), {})("EMPTY")
loose_zip = lambda a, b: zip(
list(a) + (max(len(a), len(b)) - len(a)) * [zip_empty],
list(b) + (max(len(a), len(b)) - len(b)) * [zip_empty]
)
apply_loose_zip_preserving_depth = \
lambda a, b: \
(type(a) if type(a) == type(b) else type(a))(
[apply_loose_zip_preserving_depth(*p) for p in loose_zip(a, b)]
) if tuplist(a) == tuplist(b) == True else zipped_outlier([a, b])
# as previous, but with length checking of some sort
# NOTE: automatically shortens the longer counterpart in the pair
# to the length of the bigger one
apply_strict_zip_preserving_depth = \
lambda a, b: \
(type(a) if type(a) == type(b) else type(a))(
[apply_strict_zip_preserving_depth(*p) for p in zip(a, b)]
) if tuplist(a) == tuplist(b) == True and len(a) == len(b) \
else zipped_outlier([a, b])
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