1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
|
import os
import unittest
class NamedExpressionInvalidTest(unittest.TestCase):
def test_named_expression_invalid_01(self):
code = """x := 0"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_02(self):
code = """x = y := 0"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_03(self):
code = """y := f(x)"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_04(self):
code = """y0 = y1 := f(x)"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_06(self):
code = """((a, b) := (1, 2))"""
with self.assertRaisesRegex(SyntaxError, "cannot use named assignment with tuple"):
exec(code, {}, {})
def test_named_expression_invalid_07(self):
code = """def spam(a = b := 42): pass"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_08(self):
code = """def spam(a: b := 42 = 5): pass"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_09(self):
code = """spam(a=b := 'c')"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_10(self):
code = """spam(x = y := f(x))"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_11(self):
code = """spam(a=1, b := 2)"""
with self.assertRaisesRegex(SyntaxError,
"positional argument follows keyword argument"):
exec(code, {}, {})
def test_named_expression_invalid_12(self):
code = """spam(a=1, (b := 2))"""
with self.assertRaisesRegex(SyntaxError,
"positional argument follows keyword argument"):
exec(code, {}, {})
def test_named_expression_invalid_13(self):
code = """spam(a=1, (b := 2))"""
with self.assertRaisesRegex(SyntaxError,
"positional argument follows keyword argument"):
exec(code, {}, {})
def test_named_expression_invalid_14(self):
code = """(x := lambda: y := 1)"""
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_15(self):
code = """(lambda: x := 1)"""
with self.assertRaisesRegex(SyntaxError,
"cannot use named assignment with lambda"):
exec(code, {}, {})
def test_named_expression_invalid_16(self):
code = "[i + 1 for i in i := [1,2]]"
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_17(self):
code = "[i := 0, j := 1 for i, j in [(1, 2), (3, 4)]]"
with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
exec(code, {}, {})
def test_named_expression_invalid_18(self):
code = """class Foo():
[(42, 1 + ((( j := i )))) for i in range(5)]
"""
with self.assertRaisesRegex(TargetScopeError,
"named expression within a comprehension cannot be used in a class body"):
exec(code, {}, {})
class NamedExpressionAssignmentTest(unittest.TestCase):
def test_named_expression_assignment_01(self):
(a := 10)
self.assertEqual(a, 10)
def test_named_expression_assignment_02(self):
a = 20
(a := a)
self.assertEqual(a, 20)
def test_named_expression_assignment_03(self):
(total := 1 + 2)
self.assertEqual(total, 3)
def test_named_expression_assignment_04(self):
(info := (1, 2, 3))
self.assertEqual(info, (1, 2, 3))
def test_named_expression_assignment_05(self):
(x := 1, 2)
self.assertEqual(x, 1)
def test_named_expression_assignment_06(self):
(z := (y := (x := 0)))
self.assertEqual(x, 0)
self.assertEqual(y, 0)
self.assertEqual(z, 0)
def test_named_expression_assignment_07(self):
(loc := (1, 2))
self.assertEqual(loc, (1, 2))
def test_named_expression_assignment_08(self):
if spam := "eggs":
self.assertEqual(spam, "eggs")
else: self.fail("variable was not assigned using named expression")
def test_named_expression_assignment_09(self):
if True and (spam := True):
self.assertTrue(spam)
else: self.fail("variable was not assigned using named expression")
def test_named_expression_assignment_10(self):
if (match := 10) == 10:
pass
else: self.fail("variable was not assigned using named expression")
def test_named_expression_assignment_11(self):
def spam(a):
return a
input_data = [1, 2, 3]
res = [(x, y, x/y) for x in input_data if (y := spam(x)) > 0]
self.assertEqual(res, [(1, 1, 1.0), (2, 2, 1.0), (3, 3, 1.0)])
def test_named_expression_assignment_12(self):
def spam(a):
return a
res = [[y := spam(x), x/y] for x in range(1, 5)]
self.assertEqual(res, [[1, 1.0], [2, 1.0], [3, 1.0], [4, 1.0]])
def test_named_expression_assignment_13(self):
length = len(lines := [1, 2])
self.assertEqual(length, 2)
self.assertEqual(lines, [1,2])
def test_named_expression_assignment_14(self):
"""
Where all variables are positive integers, and a is at least as large
as the n'th root of x, this algorithm returns the floor of the n'th
root of x (and roughly doubling the number of accurate bits per
iteration):
"""
a = 9
n = 2
x = 3
while a > (d := x // a**(n-1)):
a = ((n-1)*a + d) // n
self.assertEqual(a, 1)
def test_named_expression_assignment_15(self):
while a := False:
pass # This will not run
self.assertEqual(a, False)
def test_named_expression_assignment_16(self):
a, b = 1, 2
fib = {(c := a): (a := b) + (b := a + c) - b for __ in range(6)}
self.assertEqual(fib, {1: 2, 2: 3, 3: 5, 5: 8, 8: 13, 13: 21})
class NamedExpressionScopeTest(unittest.TestCase):
def test_named_expression_scope_01(self):
code = """def spam():
(a := 5)
print(a)"""
with self.assertRaisesRegex(NameError, "name 'a' is not defined"):
exec(code, {}, {})
def test_named_expression_scope_02(self):
total = 0
partial_sums = [total := total + v for v in range(5)]
self.assertEqual(partial_sums, [0, 1, 3, 6, 10])
self.assertEqual(total, 10)
def test_named_expression_scope_03(self):
containsOne = any((lastNum := num) == 1 for num in [1, 2, 3])
self.assertTrue(containsOne)
self.assertEqual(lastNum, 1)
def test_named_expression_scope_04(self):
def spam(a):
return a
res = [[y := spam(x), x/y] for x in range(1, 5)]
self.assertEqual(y, 4)
def test_named_expression_scope_05(self):
def spam(a):
return a
input_data = [1, 2, 3]
res = [(x, y, x/y) for x in input_data if (y := spam(x)) > 0]
self.assertEqual(res, [(1, 1, 1.0), (2, 2, 1.0), (3, 3, 1.0)])
self.assertEqual(y, 3)
def test_named_expression_scope_06(self):
res = [[spam := i for i in range(3)] for j in range(2)]
self.assertEqual(res, [[0, 1, 2], [0, 1, 2]])
self.assertEqual(spam, 2)
def test_named_expression_scope_07(self):
len(lines := [1, 2])
self.assertEqual(lines, [1, 2])
def test_named_expression_scope_08(self):
def spam(a):
return a
def eggs(b):
return b * 2
res = [spam(a := eggs(b := h)) for h in range(2)]
self.assertEqual(res, [0, 2])
self.assertEqual(a, 2)
self.assertEqual(b, 1)
def test_named_expression_scope_09(self):
def spam(a):
return a
def eggs(b):
return b * 2
res = [spam(a := eggs(a := h)) for h in range(2)]
self.assertEqual(res, [0, 2])
self.assertEqual(a, 2)
def test_named_expression_scope_10(self):
res = [b := [a := 1 for i in range(2)] for j in range(2)]
self.assertEqual(res, [[1, 1], [1, 1]])
self.assertEqual(a, 1)
self.assertEqual(b, [1, 1])
def test_named_expression_scope_11(self):
res = [j := i for i in range(5)]
self.assertEqual(res, [0, 1, 2, 3, 4])
self.assertEqual(j, 4)
def test_named_expression_scope_12(self):
res = [i := i for i in range(5)]
self.assertEqual(res, [0, 1, 2, 3, 4])
self.assertEqual(i, 4)
def test_named_expression_scope_13(self):
res = [i := 0 for i, j in [(1, 2), (3, 4)]]
self.assertEqual(res, [0, 0])
self.assertEqual(i, 0)
def test_named_expression_scope_14(self):
res = [(i := 0, j := 1) for i, j in [(1, 2), (3, 4)]]
self.assertEqual(res, [(0, 1), (0, 1)])
self.assertEqual(i, 0)
self.assertEqual(j, 1)
def test_named_expression_scope_15(self):
res = [(i := i, j := j) for i, j in [(1, 2), (3, 4)]]
self.assertEqual(res, [(1, 2), (3, 4)])
self.assertEqual(i, 3)
self.assertEqual(j, 4)
def test_named_expression_scope_16(self):
res = [(i := j, j := i) for i, j in [(1, 2), (3, 4)]]
self.assertEqual(res, [(2, 2), (4, 4)])
self.assertEqual(i, 4)
self.assertEqual(j, 4)
def test_named_expression_scope_17(self):
b = 0
res = [b := i + b for i in range(5)]
self.assertEqual(res, [0, 1, 3, 6, 10])
self.assertEqual(b, 10)
def test_named_expression_scope_18(self):
def spam(a):
return a
res = spam(b := 2)
self.assertEqual(res, 2)
self.assertEqual(b, 2)
def test_named_expression_scope_19(self):
def spam(a):
return a
res = spam((b := 2))
self.assertEqual(res, 2)
self.assertEqual(b, 2)
def test_named_expression_scope_20(self):
def spam(a):
return a
res = spam(a=(b := 2))
self.assertEqual(res, 2)
self.assertEqual(b, 2)
def test_named_expression_scope_21(self):
def spam(a, b):
return a + b
res = spam(c := 2, b=1)
self.assertEqual(res, 3)
self.assertEqual(c, 2)
def test_named_expression_scope_22(self):
def spam(a, b):
return a + b
res = spam((c := 2), b=1)
self.assertEqual(res, 3)
self.assertEqual(c, 2)
def test_named_expression_scope_23(self):
def spam(a, b):
return a + b
res = spam(b=(c := 2), a=1)
self.assertEqual(res, 3)
self.assertEqual(c, 2)
def test_named_expression_scope_24(self):
a = 10
def spam():
nonlocal a
(a := 20)
spam()
self.assertEqual(a, 20)
def test_named_expression_scope_25(self):
ns = {}
code = """a = 10
def spam():
global a
(a := 20)
spam()"""
exec(code, ns, {})
self.assertEqual(ns["a"], 20)
if __name__ == "__main__":
unittest.main()
|
