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Re: The worth of comments

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On 2011-05-28, Roy Smith <roy@panix.com> wrote:
> One reasonable definition of a bug is something the code
> actually does which differs from the documented interface.
> Unless you know what the code is supposed to do, how can you
> possibly look at it and say whether it has a bug or not?  For
> example, take this function:
>
> def foo():
>    l = [1, 2, 3]
>    return l[3]
>
> Is this code correct?  I'll bet most people would look at this
> and say, "I'm not sure what he had in mind, but whatever it
> was, this has to be a bug because he's indexing past the end of
> the list".  Well, what if I showed you the interface contract:
>
> def foo():
>    "Raise IndexError.  This is useful as a testing fixture."
>    l = [1, 2, 3]
>    return l[3]
>
> Now it's obvious that the function does exactly what it's
> supposed to do (even if it's not the best way to do it).

That's an excellent illustration of bad code hid by a bad comment.

Perhaps better:

def foo():
  raise IndexError()

-- 
Neil Cerutti

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The worth of comments Richard Parker <r.richardparker@comcast.net> - 2011-05-26 11:50 -0700
  Re: The worth of comments Ben Finney <ben+python@benfinney.id.au> - 2011-05-27 11:42 +1000
    Re: The worth of comments Grant Edwards <invalid@invalid.invalid> - 2011-05-27 13:54 +0000
      Re: The worth of comments Irmen de Jong <irmen@-NOSPAM-xs4all.nl> - 2011-05-27 19:05 +0200
        Re: The worth of comments Grant Edwards <invalid@invalid.invalid> - 2011-05-27 17:53 +0000
          Re: The worth of comments Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2011-05-28 15:09 +0200
            Re: The worth of comments python@bdurham.com - 2011-05-28 09:34 -0400
          Re: The worth of comments Roy Smith <roy@panix.com> - 2011-05-28 09:36 -0400
            Re: The worth of comments Chris Angelico <rosuav@gmail.com> - 2011-05-29 00:02 +1000
            Re: The worth of comments Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2011-05-28 16:05 +0200
              Re: The worth of comments Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-05-29 12:47 +1200
                Re: The worth of comments Ben Finney <ben+python@benfinney.id.au> - 2011-05-29 11:41 +1000
                Re: The worth of comments Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-05-29 23:05 +1200
                Re: The worth of comments Grant Edwards <invalid@invalid.invalid> - 2011-05-29 14:43 +0000
                Re: The worth of comments Roy Smith <roy@panix.com> - 2011-05-29 11:39 -0400
                Re: The worth of comments Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2011-05-29 03:49 +0200
                Re: The worth of comments Alister Ware <alister.ware@ntlworld.com> - 2011-05-29 17:26 +0000
            Re: The worth of comments Neil Cerutti <neilc@norwich.edu> - 2011-05-31 14:47 +0000
  Re: The worth of comments Roy Smith <roy@panix.com> - 2011-05-26 22:08 -0400
    Re: The worth of comments Chris Angelico <rosuav@gmail.com> - 2011-05-27 15:13 +1000
      Re: The worth of comments Roy Smith <roy@panix.com> - 2011-05-27 09:25 -0400
    Re: The worth of comments Tim Roberts <timr@probo.com> - 2011-05-27 00:02 -0700
      Re: The worth of comments "D'Arcy J.M. Cain" <darcy@druid.net> - 2011-05-27 09:29 -0400
    RE: The worth of comments "Prasad, Ramit" <ramit.prasad@jpmchase.com> - 2011-05-27 14:17 -0400

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