antipattern.py

g = [locals().__setitem__('_x', (yield locals().get('_x', x)) or locals().get('_x', x)) for x in range(10)]
# >>> next(g)
# 0
# >>> next(g)
# 0
# >>> g.send(3)
# 3
# >>> next(g)
# 3
# >>> next(g)
# 3
# >>> g.send(4)
# 4

send_writer = lambda filename, max_lines: (lambda next_shim_target: (next_shim_target, next(next_shim_target))[0])((lambda file: [file.write((yield lines_written)) for lines_written in range(max_lines)])(open(filename, 'w')))
# >>> writer = send_writer('x.txt', 1000)
# >>> writer.send('lol\n')
# 1
# >>> writer.send("please don't do this")
# 2
# >>> writer.close()
# >>> open('x.txt').read()
# "lol\npleasedon't do this"