cpython.git - https://github.com/python/cpython.git

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Diffstat (limited to 'Mac/BuildScript/build-installer.py')

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# Tests for extended unpacking, starred expressions. doctests = """ Unpack tuple >>> t = (1, 2, 3) >>> a, *b, c = t >>> a == 1 and b == [2] and c == 3 True Unpack list >>> l = [4, 5, 6] >>> a, *b = l >>> a == 4 and b == [5, 6] True Unpack implied tuple >>> *a, = 7, 8, 9 >>> a == [7, 8, 9] True Unpack string... fun! >>> a, *b = 'one' >>> a == 'o' and b == ['n', 'e'] True Unpack long sequence >>> a, b, c, *d, e, f, g = range(10) >>> (a, b, c, d, e, f, g) == (0, 1, 2, [3, 4, 5, 6], 7, 8, 9) True Unpack short sequence >>> a, *b, c = (1, 2) >>> a == 1 and c == 2 and b == [] True Unpack generic sequence >>> class Seq: ... def __getitem__(self, i): ... if i >= 0 and i < 3: return i ... raise IndexError ... >>> a, *b = Seq() >>> a == 0 and b == [1, 2] True Unpack in for statement >>> for a, *b, c in [(1,2,3), (4,5,6,7)]: ... print(a, b, c) ... 1 [2] 3 4 [5, 6] 7 Unpack in list >>> [a, *b, c] = range(5) >>> a == 0 and b == [1, 2, 3] and c == 4 True Multiple targets >>> a, *b, c = *d, e = range(5) >>> a == 0 and b == [1, 2, 3] and c == 4 and d == [0, 1, 2, 3] and e == 4 True Now for some failures Unpacking non-sequence >>> a, *b = 7 Traceback (most recent call last): ... TypeError: 'int' object is not iterable Unpacking sequence too short >>> a, *b, c, d, e = Seq() Traceback (most recent call last): ... ValueError: need more than 3 values to unpack Unpacking a sequence where the test for too long raises a different kind of error >>> class BozoError(Exception): ... pass ... >>> class BadSeq: ... def __getitem__(self, i): ... if i >= 0 and i < 3: ... return i ... elif i == 3: ... raise BozoError ... else: ... raise IndexError ... Trigger code while not expecting an IndexError (unpack sequence too long, wrong error) >>> a, *b, c, d, e = BadSeq() Traceback (most recent call last): ... test.test_unpack_ex.BozoError Now some general starred expressions (all fail). >>> a, *b, c, *d, e = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: two starred expressions in assignment >>> [*b, *c] = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: two starred expressions in assignment >>> *a = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: starred assignment target must be in a list or tuple >>> *a # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target >>> *1 # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target >>> x = *a # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target Some size constraints (all fail.) >>> s = ", ".join("a%d" % i for i in range(1<<8)) + ", *rest = range(1<<8 + 1)" >>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: too many expressions in star-unpacking assignment >>> s = ", ".join("a%d" % i for i in range(1<<8 + 1)) + ", *rest = range(1<<8 + 2)" >>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: too many expressions in star-unpacking assignment (there is an additional limit, on the number of expressions after the '*rest', but it's 1<<24 and testing it takes too much memory.) """ __test__ = {'doctests' : doctests} def test_main(verbose=False): import sys from test import support from test import test_unpack_ex support.run_doctest(test_unpack_ex, verbose) if __name__ == "__main__": test_main(verbose=True)


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