In [1]:

    

with open('clockdeco.py') as fp:
    src = fp.read(60)


    

In [2]:

    

len(src)


    

    
Out[2]:





60

In [3]:

    

fp


    

    
Out[3]:





<_io.TextIOWrapper name='clockdeco.py' mode='r' encoding='cp1252'>

In [4]:

    

fp.closed, fp.encoding


    

    
Out[4]:





(True, 'cp1252')

In [5]:

    

fp.read(60)


    

    




---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-5-5fbd86132515> in <module>()
----> 1 fp.read(60)

ValueError: I/O operation on closed file.

In [33]:

    

from mirror import LookingGlass


    

In [2]:

    

with LookingGlass() as what:
    print('Alice, Kitty and Snowdrop')
    print(what)


    

    




pordwonS dna yttiK ,ecilA
YKCOWREBBAJ

In [8]:

    

from mirror import LookingGlass
manager = LookingGlass()
manager


    

    
Out[8]:





<mirror.LookingGlass at 0x86cd35afd0>

In [13]:

    

monster = manager.__enter__()


    

In [14]:

    

monster == 'JABBERWOCKY'


    

    
Out[14]:





True

In [15]:

    

monster


    

    
Out[15]:





'JABBERWOCKY'

In [16]:

    

manager


    

    
Out[16]:





<mirror.LookingGlass at 0x86cd35afd0>

In [17]:

    

manager.__exit__(None, None, None)


    

In [18]:

    

monster


    

    
Out[18]:





'JABBERWOCKY'

In [21]:

    

# from mirror_gen import looking_glass
# with looking_glass() as what:
#     print('Alice, Kitty and Snowdrop')
#     print(what)


    

In [24]:

    

import contextlib

@contextlib.contextmanager
def looking_glass():
    import sys
    original_write = sys.stdout.write
    
    def reverse_write(text):
        original_write(text[::-1])
        
    sys.stdout.write = reverse_write
    msg = ''
    try:
        yield 'JABBERWOCKY'
    except ZeroDivisionError:
        msg = 'Please DO NOT divice by zero!'
    finally:
        sys.stdout.write = original_write
        if msg:
            print(msg)


    

In [ ]: