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ch18: update from book draft

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This commit is contained in:
Luciano Ramalho 2020-02-19 00:15:20 -03:00
parent d63b4844f1
commit 0ca34e2676
3 changed files with 22 additions and 22 deletions
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16
18-context-mngr/mirror.py
View File

@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context.
While active, the context manager reverses text output to
``stdout``::
# BEGIN MIRROR_DEMO_1
# tag::MIRROR_DEMO_1[]
>>> from mirror import LookingGlass
>>> with LookingGlass() as what: # <1>
@ -18,12 +18,12 @@ While active, the context manager reverses text output to
>>> print('Back to normal.') # <5>
Back to normal.
# END MIRROR_DEMO_1
# end::MIRROR_DEMO_1[]
This exposes the context manager operation::
# BEGIN MIRROR_DEMO_2
# tag::MIRROR_DEMO_2[]
>>> from mirror import LookingGlass
>>> manager = LookingGlass() # <1>
@ -40,11 +40,11 @@ This exposes the context manager operation::
>>> monster
'JABBERWOCKY'
# END MIRROR_DEMO_2
# end::MIRROR_DEMO_2[]
The context manager can handle and "swallow" exceptions.
# BEGIN MIRROR_DEMO_3
# tag::MIRROR_DEMO_3[]
>>> from mirror import LookingGlass
>>> with LookingGlass():
@ -63,12 +63,12 @@ The context manager can handle and "swallow" exceptions.
...
NameError: name 'no_such_name' is not defined
# END MIRROR_DEMO_3
# end::MIRROR_DEMO_3[]
"""
# BEGIN MIRROR_EX
# tag::MIRROR_EX[]
class LookingGlass:
def __enter__(self): # <1>
@ -89,4 +89,4 @@ class LookingGlass:
# <11>
# END MIRROR_EX
# end::MIRROR_EX[]

12
18-context-mngr/mirror_gen.py
View File

@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context manager.
While active, the context manager reverses text output to
``stdout``::
# BEGIN MIRROR_GEN_DEMO_1
# tag::MIRROR_GEN_DEMO_1[]
>>> from mirror_gen import looking_glass
>>> with looking_glass() as what: # <1>
@ -16,12 +16,12 @@ While active, the context manager reverses text output to
>>> what
'JABBERWOCKY'
# END MIRROR_GEN_DEMO_1
# end::MIRROR_GEN_DEMO_1[]
This exposes the context manager operation::
# BEGIN MIRROR_GEN_DEMO_2
# tag::MIRROR_GEN_DEMO_2[]
>>> from mirror_gen import looking_glass
>>> manager = looking_glass() # <1>
@ -38,12 +38,12 @@ This exposes the context manager operation::
>>> monster
'JABBERWOCKY'
# END MIRROR_GEN_DEMO_2
# end::MIRROR_GEN_DEMO_2[]
"""
# BEGIN MIRROR_GEN_EX
# tag::MIRROR_GEN_EX[]
import contextlib
@ -61,4 +61,4 @@ def looking_glass():
sys.stdout.write = original_write # <6>
# END MIRROR_GEN_EX
# end::MIRROR_GEN_EX[]

16
18-context-mngr/mirror_gen_exc.py
View File

@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context manager.
While active, the context manager reverses text output to
``stdout``::
# BEGIN MIRROR_GEN_DEMO_1
# tag::MIRROR_GEN_DEMO_1[]
>>> from mirror_gen import looking_glass
>>> with looking_glass() as what: # <1>
@ -16,12 +16,12 @@ While active, the context manager reverses text output to
>>> what
'JABBERWOCKY'
# END MIRROR_GEN_DEMO_1
# end::MIRROR_GEN_DEMO_1[]
This exposes the context manager operation::
# BEGIN MIRROR_GEN_DEMO_2
# tag::MIRROR_GEN_DEMO_2[]
>>> from mirror_gen import looking_glass
>>> manager = looking_glass() # <1>
@ -38,7 +38,7 @@ This exposes the context manager operation::
>>> monster
'JABBERWOCKY'
# END MIRROR_GEN_DEMO_2
# end::MIRROR_GEN_DEMO_2[]
The context manager can handle and "swallow" exceptions.
The following test does not pass under doctest (a
@ -46,7 +46,7 @@ ZeroDivisionError is reported by doctest) but passes
if executed by hand in the Python 3 console (the exception
is handled by the context manager):
# BEGIN MIRROR_GEN_DEMO_3
# tag::MIRROR_GEN_DEMO_3[]
>>> from mirror_gen import looking_glass
>>> with looking_glass():
@ -57,7 +57,7 @@ is handled by the context manager):
ytpmuD ytpmuH
Please DO NOT divide by zero!
# END MIRROR_GEN_DEMO_3
# end::MIRROR_GEN_DEMO_3[]
>>> with looking_glass():
... print('Humpty Dumpty')
@ -73,7 +73,7 @@ is handled by the context manager):
"""
# BEGIN MIRROR_GEN_EXC
# tag::MIRROR_GEN_EXC[]
import contextlib
@ -98,4 +98,4 @@ def looking_glass():
print(msg) # <4>
# END MIRROR_GEN_EXC
# end::MIRROR_GEN_EXC[]