> On 13 Oct 2020, at 16:08, [email protected] wrote:
>
> Steven,
> Thanks for the responses. In response to your responses....:
> Steven D'Aprano wrote:
>> Hi jmward01,
>> I'm not really sure what you mean by "boilerplate heavy objects".
>> Boilerplate generally applies to the amount of source code you have to
>> write. I don't think that a two line class (perhaps a couple of extra
>> lines if you give it a docstring) justifies the name "boilerplate":
>> class MySpecialException(Exception):
>> pass
>>
>> In my experience, that covers the majority of custom exceptions I've
>> needed. (More on this below.)
>> As for "heavy objects", it's true that classes are moderately
>> heavyweight:
>> py> sys.getsizeof(Exception)
>> 400
>>
>> but the instances are relatively lightweight:
>> py> sys.getsizeof(Exception('spam eggs'))
>> 96
>>
>> and if you're stressed out by that, you might be using the wrong
>> language :-)
>> So I'm not quite sure what specific part of this you are worried about:
>> memory consumption or lines of code.
> I am not particularly concerned with performance here. I am more worried
> about code clarity, boilerplate that de-incentivizes a feature and hidden
> values. The current exception mechanism encourages passing, effectively,
> un-named lists of parameters or building boilerplate to create the equivalent
> of named tuples (e.args[0] or building an __init__ that defines members). If
> the only value is the name, why not just define it where you use it instead
> of creating an intermediary class definition? I use string literals for state
> names all the time instead of creating objects and importing them all over my
> code because most of the time the mental overhead of imports and the like
> isn't worth the ease and clarity of just passing a string. This is the same
> argument I am making for most exceptions by suggesting this syntax.
Using exception.args or an explicit __init__ isn’t necessary:
#— (python 3.9)
import dataclasses
@dataclasses.dataclass
class MyException (Exception):
a : int
b : str
try:
raise MyException(a=1, b="hello")
except MyException as exc:
print(f"{exc.a=}, {exc.b=}”)
# —
Ronald
—
Twitter / micro.blog: @ronaldoussoren
Blog: https://blog.ronaldoussoren.net/
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