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@ssanderson
Created September 14, 2017 13:25
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"Functional" Switchcase Example
from codetransformer.transformers.switchcase import switch
def foo(x):
print("Start: x={}".format(x))
with switch(x) as case:
@case(1)
def _1():
# Read and write x.
x = 'x was ' + str(x)
@case(2)
def _2():
# Introduce a new "local".
y = 'introduced y'
@case(3)
def _3():
# See the mutations from cases 1 and 2.
z = {'x': x, 'y': y}
break_ # Break out of the case construct.
@case(4)
def _4():
assert False, "Shouldn't be hit."
# See the mutations introduced in the cases.
print("End: x={!r}, y={!r}, z={!r}".format(x, y, z))
foo(1)
# Prints:
# -- Start: x=1
# -- End: x='x was 1', y='introduced y', z={'y': 'introduced y', 'x': 'x was 1'}
foo(2)
# Prints:
# -- Start: x=2
# -- End: x=2, y='introduced y', z={'y': 'introduced y', 'x': 2}
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