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Re: etiology of exceptions

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On 9/25/12 7:29 AM, bob wrote:
> What is the etiology of exceptions?  Did they come about because people got tired of having to check a return value every time they called a function?
>
I don't know of how they came to be, but I can list several benefits.

1. The Error Condition and the Error Handler which-could-handle-it were 
often separated by several levels of calls.

2. Having a "magic" return value isn't always possible, or desirable, so 
some other mechanism needed to be employed.  Passing an argument by 
reference has additional overhead for a hopefully rare case.

3. In some languages, Exceptions can be compile-time checked, which 
helps reduce the number of bugs.  The compiler can even use its typing 
system to ensure that the *correct* exceptions are handled, further 
reducing human error.

4. Exceptions also allow easy polymorphism of error cases. Because of 
this, they are useful in more OO design patterns over simple return values.

5. In complicated programs, it is easier to visualize flow of execution 
with fewer "if" statements.  Using exceptions allows easier 
understanding of the "normal" flow vs "exceptional" flow.  It also helps 
to understand what code is actually responsible for handling error 
conditions (since its concentrated in the catch blocks).

This is all just off the top of my head, and some of it may be arguable, 
but IMHO the argument that you can just check return values is flawed. 
You *can* just check return values, just as you *can* turn off a 
light-bulb by unscrewing it.  There just is a better way.

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etiology of exceptions bob <bob@coolfone.comze.com> - 2012-09-25 07:29 -0700
  Re: etiology of exceptions Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-09-25 09:15 -0700
    Re: etiology of exceptions "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-09-25 18:50 +0200
    Re: etiology of exceptions Willem <willem@turtle.stack.nl> - 2012-09-25 20:51 +0000
      Re: etiology of exceptions Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-09-25 15:32 -0700
  Re: etiology of exceptions James Dow Allen <jdallen2000@yahoo.com> - 2012-09-25 23:43 -0700
  Re: etiology of exceptions "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2012-09-28 08:07 +0100
    Re: etiology of exceptions Rui Maciel <rui.maciel@gmail.com> - 2012-09-28 09:47 +0100
  Re: etiology of exceptions jussi.santti@ard.fi - 2012-10-07 23:13 -0700
    Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-08 22:37 +0100
      Re: etiology of exceptions Ian Collins <ian-news@hotmail.com> - 2012-10-09 10:46 +1300
        Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-08 22:52 +0100
    Re: etiology of exceptions Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-10 08:06 -0700
      Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-10 18:24 +0100
        Re: etiology of exceptions Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-11 05:35 -0700
          Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-11 14:40 +0100
            Re: etiology of exceptions Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-11 08:20 -0700
            Re: etiology of exceptions jussi.santti@ard.fi - 2012-10-15 08:28 -0700
              Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-15 22:13 +0100
          Re: etiology of exceptions Rui Maciel <rui.maciel@gmail.com> - 2012-10-11 15:35 +0100
            Re: etiology of exceptions Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-11 08:21 -0700
      Re: etiology of exceptions jussi.santti@ard.fi - 2012-10-15 08:10 -0700
        Re: etiology of exceptions "LudovicoVan" <julio@diegidio.name> - 2012-10-15 22:16 +0100

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