weave.blitz assignment bug.

blitz_bug.py

import numpy as np
from scipy.weave import blitz
import numpy.testing as npt


def test_blitz_bug():
    """Assignment to arr[i:] fails inside blitz expression."""
    N = 4
    expr_buggy = 'arr_blitz_buggy[{0}:] = arr[{0}:]'
    expr_not_buggy = 'arr_blitz_not_buggy[{0}:{1}] = arr[{0}:]'
    np.random.seed(7)
    arr = np.random.randn(N)
    sh = arr.shape[0]
    for lim in [0, 1, 2]:
        arr_blitz_buggy, arr_blitz_not_buggy, arr_np = np.zeros(N), np.zeros(N), np.zeros(N)
        blitz(expr_buggy.format(lim))
        blitz(expr_not_buggy.format(lim, 'sh'))
        arr_np[lim:] = arr[lim:]
        npt.assert_allclose(arr_blitz_buggy, arr_np)
        npt.assert_allclose(arr_blitz_not_buggy, arr_np)

if __name__ == '__main__':
    test_blitz_bug()