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Re: Re: What Are The Rules For Subs And Modules When Fed Wrong Input

by PhiRatE (Monk)
on Jul 22, 2002 at 01:16 UTC ( #183908=note: print w/replies, xml ) Need Help??


in reply to Re: What Are The Rules For Subs And Modules When Fed Wrong Input
in thread What Are The Rules For Subs And Modules When Fed Wrong Input

I disagree. Die. Always die. Die on everything except success.

The reasoning behind this is simple. Its easy to handle an exception, you can catch it, you can ignore it, you can re-throw it. All of this without cluttering the interface with random error variables and having to test returns at every single operation.

Exceptions didn't catch on for no reason, they are an elegant and effective method of error handling and indeed I find myself having a very hard time writing software in languages that don't support them.

Let us take the example of a database error for example. If the DBI module threw useful exceptions when things went wrong, I would no longer have to sit there checking the return on every little operation to make sure things went ok. I could wrap my entire atomic operation in an eval {}, catch any exceptions I found relevant and re-start the entire operation or provide *useful* input to the user if necessary. Easy, clean, effective.

Think twice before dissing die(), its a big strength. That said, no interface should die() without the documentation stating what exceptions are thrown and when :)

  • Comment on Re: Re: What Are The Rules For Subs And Modules When Fed Wrong Input

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Re: Re: Re: What Are The Rules For Subs And Modules When Fed Wrong Input
by gav^ (Curate) on Jul 22, 2002 at 02:03 UTC
    If the DBI module threw useful exceptions when things went wrong, I would no longer have to sit there checking the return on every little operation to make sure things went ok. I could wrap my entire atomic operation in an eval {}, catch any exceptions I found relevant and re-start the entire operation or provide *useful* input to the user if necessary.
    Strangely enough you can do that. It's just a matter of reading through the documentation (1.30 here, 1.19 here).

    You can use the RaiseError, PrintError (and on later DBI versions) HandleError database handles to pull this off. If you download Tim Bunce's Advanced Perl DBI slides there is more information.

    Hope this helps...

    gav^

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