On Fri, 2009-12-18 at 07:12 -0500, Neal Becker wrote: > I haven't tried it, but it sounds really cool. I suppose I should expect a > lot more overhead compared to try/except, since it's not built-in to python?
It's a pretty thin layer on top of try/except so I'll be surprised if
there is *too* much overhead. The only overhead is at establishment
and/or invocation time - calling some extra functions, walking a few
stack frames, etc.
I've attached a highly scientific benchmark I threw together this
morning. Results:
Establishing a restart/tryexcept but not using it:
test_tryexcept0: 1.23 usec
test_restarts0: 34.90 usec
Establishing a restart/tryexcept, returning a new value:
test_tryexcept1: 3.56 usec
test_restarts1: 67.30 usec
Establishing a restart/tryexcept, raising a new error:
test_tryexcept2: 5.86 usec
test_restarts2: 90.20 usec
Not having to pass status flags or callback functions through every
layer of your API to properly recover from errors:
tryexcept: impossible :-(
withrestart: priceless :-)
Cheers,
Ryan
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from withrestart import *
def test_tryexcept0():
def raiser():
return 7
def invoker():
return raiser()
def catcher():
try:
return invoker()
except ValueError:
return 7
assert catcher() == 7
def test_tryexcept1():
def raiser():
raise ValueError
def invoker():
return raiser()
def catcher():
try:
return invoker()
except ValueError:
return 7
assert catcher() == 7
def test_tryexcept2():
def raiser():
raise ValueError
def invoker():
raiser()
def catcher():
try:
invoker()
except ValueError:
raise TypeError
try:
catcher()
except TypeError:
pass
else:
raise AssertionError
def test_restarts0():
def raiser():
return 7
def invoker():
with restarts(use_value) as invoke:
return invoke(raiser)
def catcher():
with Handler(ValueError,"use_value",7):
return invoker()
assert catcher() == 7
def test_restarts1():
def raiser():
raise ValueError
def invoker():
with restarts(use_value) as invoke:
return invoke(raiser)
def catcher():
with Handler(ValueError,"use_value",7):
return invoker()
assert catcher() == 7
def test_restarts2():
def raiser():
raise ValueError
def invoker():
with restarts(raise_error) as invoke:
invoke(raiser)
def catcher():
with Handler(ValueError,"raise_error",TypeError):
invoker()
try:
catcher()
except TypeError:
pass
else:
raise AssertionError
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