[Baypiggies] Python way to avoid usage of raise

[Nick S Kanakakorn]

Hi Andy,

Thanks for your comment.  I could wrap this in a class but I'm not so sure
how it would save me to have to do something like this.

class ReturnWrapper(object):
     def __init__(error_code, error_message, real_return_result)
           ....

def f1(arg):
    try
        x = some_function()
    except IndexError, e
        return ReturnWrapper(-1,'some error message' , None)
    # all good here
    return ReturnWrapper(0, None, 'some good value')

def f1caller()
    obj = f1(param1)
    if (obj.error_code < 0):
       # handle some error or just return obj
       return obj
    foo....
    obj = f1(param2)
    if (obj.error_code < 0):
       # handle some error or just return obj
       return obj
    bar....


I still have to use this pattern     if (obj.error_code < 0):  ....
It does not really make my code smaller than using tuple.
I used to code C similar to what you said I did not expect to have to do
the
same thing in python

Thanks,

On Tue, Oct 5, 2010 at 9:42 PM, Andy Wiggin <andywiggin at gmail.com> wrote:

> I must agree with the "it's an unmitigated disaster" comments already
> posted. But it does remind me of a C coding convention that was the
> standard at a company worked at a long time ago. Here, the return
> value from a function was always a coded int value where part of the
> int told you the boolean pass/fail info, part encoded the severity,
> part the product id, and part the specific message that could be
> looked up to print. All packed into 32 bits. The analogy I can think
> of is that you might want to return an instance of a standard class
> instead of a raw tuple. It could have pass/fail info, perhaps more
> extended info, plus a generic "payload" that would carry whatever the
> function was really trying to return. This would at least save you
> from interpreting ad hoc tuples everywhere, and might be a basis for
> building something a bit more elegant.
>
> -Andy
>
> On Tue, Oct 5, 2010 at 9:16 PM, Nick S Kanakakorn <bbdada at gmail.com>
> wrote:
> > I don't want to do this.  There is someone that against throwing
> exception
> > and that person has more seniority than me. He put in a guideline.  I
> lost
> > in the debate.  There is no proper research done and all the decisions
> were
> > made in less than 1 day.
> >
> > On Tue, Oct 5, 2010 at 9:03 PM, Tung Wai Yip <tungwaiyip at yahoo.com>
> wrote:
> >>
> >> Why do you want to do this? Is this just an internal coding guideline?
> Or
> >> is it done for interfacing to another language or running on
> non-standard
> >> VM? Is this apply to new code only or do you want to update existing
> code as
> >> well?
> >>
> >> There is no equivalent of C macro in Python. Just apply every code
> change
> >> as you describe it. Build a tuple every time you return something.
> Change
> >> raise into returning tuple. And change ever function call to expecting a
> >> tuple return value. I can't think of anything smarter. it looks like a
> >> complete disaster anyway.
> >>
> >> Wai yip
> >>
> >>
> >>
> >>> Let's skip the rationale discussion although I feel better for your
> >>> sympathy.  One non python solution I can think of is Macro (C/C++) or
> add
> >>> a
> >>> new command  which could work in any stack frame (TCL).
> >>> However, I'm quite new to python so I'm not so sure if there are some
> >>> ways
> >>> around this.
> >>>
> >>> Can we have something similar to macro in python ?
> >>>
> >>> On Tue, Oct 5, 2010 at 7:27 PM, Glen Jarvis <glen at glenjarvis.com>
> wrote:
> >>>
> >>>>
> >>>> > My work place has imposed a rules for no use of exception (catching
> is
> >>>> allowed).
> >>>>
> >>>> What?!?
> >>>>
> >>>> Forgive my reaction, I'm just very surprised. Why has your workplace
> >>>> implemented this policy? Has anyone else on BayPIGgies seen a  policy
> >>>> like
> >>>> this? What's the rationale?  Am I a Luddite for not hearing on this?
> >>>>
> >>>> I'm sorry. I know you asked a genuine question and I haven't answered
> >>>> it. I
> >>>> just found this very odd and am first getting my head around the
> >>>> question.
> >>>>
> >>>> Cheers,
> >>>>
> >>>>
> >>>> Glen
> >>>>
> >>>>
> >>>
> >>>
> >>
> >>
> >> --
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> >
> >
> >
> > --
> > -Nick Kanakakorn
> >
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>



-- 
-Nick Kanakakorn
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