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comparison planemo/lib/python3.7/site-packages/past/builtins/noniterators.py @ 1:56ad4e20f292 draft

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"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"
author guerler
date Fri, 31 Jul 2020 00:32:28 -0400
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0:d30785e31577 1:56ad4e20f292
1 """
2 This module is designed to be used as follows::
3
4 from past.builtins.noniterators import filter, map, range, reduce, zip
5
6 And then, for example::
7
8 assert isinstance(range(5), list)
9
10 The list-producing functions this brings in are::
11
12 - ``filter``
13 - ``map``
14 - ``range``
15 - ``reduce``
16 - ``zip``
17
18 """
19
20 from __future__ import division, absolute_import, print_function
21
22 from itertools import chain, starmap
23 import itertools # since zip_longest doesn't exist on Py2
24 from past.types import basestring
25 from past.utils import PY3
26
27
28 def flatmap(f, items):
29 return chain.from_iterable(map(f, items))
30
31
32 if PY3:
33 import builtins
34
35 # list-producing versions of the major Python iterating functions
36 def oldfilter(*args):
37 """
38 filter(function or None, sequence) -> list, tuple, or string
39
40 Return those items of sequence for which function(item) is true.
41 If function is None, return the items that are true. If sequence
42 is a tuple or string, return the same type, else return a list.
43 """
44 mytype = type(args[1])
45 if isinstance(args[1], basestring):
46 return mytype().join(builtins.filter(*args))
47 elif isinstance(args[1], (tuple, list)):
48 return mytype(builtins.filter(*args))
49 else:
50 # Fall back to list. Is this the right thing to do?
51 return list(builtins.filter(*args))
52
53 # This is surprisingly difficult to get right. For example, the
54 # solutions here fail with the test cases in the docstring below:
55 # http://stackoverflow.com/questions/8072755/
56 def oldmap(func, *iterables):
57 """
58 map(function, sequence[, sequence, ...]) -> list
59
60 Return a list of the results of applying the function to the
61 items of the argument sequence(s). If more than one sequence is
62 given, the function is called with an argument list consisting of
63 the corresponding item of each sequence, substituting None for
64 missing values when not all sequences have the same length. If
65 the function is None, return a list of the items of the sequence
66 (or a list of tuples if more than one sequence).
67
68 Test cases:
69 >>> oldmap(None, 'hello world')
70 ['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
71
72 >>> oldmap(None, range(4))
73 [0, 1, 2, 3]
74
75 More test cases are in test_past.test_builtins.
76 """
77 zipped = itertools.zip_longest(*iterables)
78 l = list(zipped)
79 if len(l) == 0:
80 return []
81 if func is None:
82 result = l
83 else:
84 result = list(starmap(func, l))
85
86 # Inspect to see whether it's a simple sequence of tuples
87 try:
88 if max([len(item) for item in result]) == 1:
89 return list(chain.from_iterable(result))
90 # return list(flatmap(func, result))
91 except TypeError as e:
92 # Simple objects like ints have no len()
93 pass
94 return result
95
96 ############################
97 ### For reference, the source code for Py2.7 map function:
98 # static PyObject *
99 # builtin_map(PyObject *self, PyObject *args)
100 # {
101 # typedef struct {
102 # PyObject *it; /* the iterator object */
103 # int saw_StopIteration; /* bool: did the iterator end? */
104 # } sequence;
105 #
106 # PyObject *func, *result;
107 # sequence *seqs = NULL, *sqp;
108 # Py_ssize_t n, len;
109 # register int i, j;
110 #
111 # n = PyTuple_Size(args);
112 # if (n < 2) {
113 # PyErr_SetString(PyExc_TypeError,
114 # "map() requires at least two args");
115 # return NULL;
116 # }
117 #
118 # func = PyTuple_GetItem(args, 0);
119 # n--;
120 #
121 # if (func == Py_None) {
122 # if (PyErr_WarnPy3k("map(None, ...) not supported in 3.x; "
123 # "use list(...)", 1) < 0)
124 # return NULL;
125 # if (n == 1) {
126 # /* map(None, S) is the same as list(S). */
127 # return PySequence_List(PyTuple_GetItem(args, 1));
128 # }
129 # }
130 #
131 # /* Get space for sequence descriptors. Must NULL out the iterator
132 # * pointers so that jumping to Fail_2 later doesn't see trash.
133 # */
134 # if ((seqs = PyMem_NEW(sequence, n)) == NULL) {
135 # PyErr_NoMemory();
136 # return NULL;
137 # }
138 # for (i = 0; i < n; ++i) {
139 # seqs[i].it = (PyObject*)NULL;
140 # seqs[i].saw_StopIteration = 0;
141 # }
142 #
143 # /* Do a first pass to obtain iterators for the arguments, and set len
144 # * to the largest of their lengths.
145 # */
146 # len = 0;
147 # for (i = 0, sqp = seqs; i < n; ++i, ++sqp) {
148 # PyObject *curseq;
149 # Py_ssize_t curlen;
150 #
151 # /* Get iterator. */
152 # curseq = PyTuple_GetItem(args, i+1);
153 # sqp->it = PyObject_GetIter(curseq);
154 # if (sqp->it == NULL) {
155 # static char errmsg[] =
156 # "argument %d to map() must support iteration";
157 # char errbuf[sizeof(errmsg) + 25];
158 # PyOS_snprintf(errbuf, sizeof(errbuf), errmsg, i+2);
159 # PyErr_SetString(PyExc_TypeError, errbuf);
160 # goto Fail_2;
161 # }
162 #
163 # /* Update len. */
164 # curlen = _PyObject_LengthHint(curseq, 8);
165 # if (curlen > len)
166 # len = curlen;
167 # }
168 #
169 # /* Get space for the result list. */
170 # if ((result = (PyObject *) PyList_New(len)) == NULL)
171 # goto Fail_2;
172 #
173 # /* Iterate over the sequences until all have stopped. */
174 # for (i = 0; ; ++i) {
175 # PyObject *alist, *item=NULL, *value;
176 # int numactive = 0;
177 #
178 # if (func == Py_None && n == 1)
179 # alist = NULL;
180 # else if ((alist = PyTuple_New(n)) == NULL)
181 # goto Fail_1;
182 #
183 # for (j = 0, sqp = seqs; j < n; ++j, ++sqp) {
184 # if (sqp->saw_StopIteration) {
185 # Py_INCREF(Py_None);
186 # item = Py_None;
187 # }
188 # else {
189 # item = PyIter_Next(sqp->it);
190 # if (item)
191 # ++numactive;
192 # else {
193 # if (PyErr_Occurred()) {
194 # Py_XDECREF(alist);
195 # goto Fail_1;
196 # }
197 # Py_INCREF(Py_None);
198 # item = Py_None;
199 # sqp->saw_StopIteration = 1;
200 # }
201 # }
202 # if (alist)
203 # PyTuple_SET_ITEM(alist, j, item);
204 # else
205 # break;
206 # }
207 #
208 # if (!alist)
209 # alist = item;
210 #
211 # if (numactive == 0) {
212 # Py_DECREF(alist);
213 # break;
214 # }
215 #
216 # if (func == Py_None)
217 # value = alist;
218 # else {
219 # value = PyEval_CallObject(func, alist);
220 # Py_DECREF(alist);
221 # if (value == NULL)
222 # goto Fail_1;
223 # }
224 # if (i >= len) {
225 # int status = PyList_Append(result, value);
226 # Py_DECREF(value);
227 # if (status < 0)
228 # goto Fail_1;
229 # }
230 # else if (PyList_SetItem(result, i, value) < 0)
231 # goto Fail_1;
232 # }
233 #
234 # if (i < len && PyList_SetSlice(result, i, len, NULL) < 0)
235 # goto Fail_1;
236 #
237 # goto Succeed;
238 #
239 # Fail_1:
240 # Py_DECREF(result);
241 # Fail_2:
242 # result = NULL;
243 # Succeed:
244 # assert(seqs);
245 # for (i = 0; i < n; ++i)
246 # Py_XDECREF(seqs[i].it);
247 # PyMem_DEL(seqs);
248 # return result;
249 # }
250
251 def oldrange(*args, **kwargs):
252 return list(builtins.range(*args, **kwargs))
253
254 def oldzip(*args, **kwargs):
255 return list(builtins.zip(*args, **kwargs))
256
257 filter = oldfilter
258 map = oldmap
259 range = oldrange
260 from functools import reduce
261 zip = oldzip
262 __all__ = ['filter', 'map', 'range', 'reduce', 'zip']
263
264 else:
265 import __builtin__
266 # Python 2-builtin ranges produce lists
267 filter = __builtin__.filter
268 map = __builtin__.map
269 range = __builtin__.range
270 reduce = __builtin__.reduce
271 zip = __builtin__.zip
272 __all__ = []