If a method, why not a property? On Jul 4, 2017 2:41 PM, "Terry Reedy" <tjreedy@udel.edu> wrote:
On 7/4/2017 3:32 PM, David Mertz wrote:
I don't see the usefulness rich exception data as at all as limited as this. Here's some toy code that shows a use:
----
# For some reason, imports might not be ready immediately # Maybe flaky network drive, maybe need to install modules, etc # The overall program can do things too make them available lazy_import("foo", "bar", "baz", "blat")
while True: try: x = foo(1) * bar(2) + baz(3)**blat(4) break except NameError as err: lazy_import(err.name <http://err.name>) sleep(1)
Alternate proposal: give the NameError class a .name instance method that extracts the name from the message. This should not increase the time to create an instance. You would then write 'err.name()' instead of ' err.name'. For 3.6
def name(self): msg = self.args[0] return msg[6:msg.rindex("'")]
# current test
try: xyz except NameError as e: print(name(e) == 'xyz')
# Exceptions unittest to ensure that the method # stays synchronized with future versions of instances
def test_nameerror_name(self): try: xyz except NameError as e: self.assertEqual(e.name(), 'xyz')
Generalize to other exceptions.
Further only-partially baked idea: Since exceptions are (in cpython) coded in C, I wonder if C data could be inexpensively attached to the instance to be retrieved and converted to python objects by methods when needed.
-- Terry Jan Reedy
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