From: dblack@...
Date: 2006-07-13T05:08:11+09:00
Subject: Re: Help with a regexp

Hi --

On Thu, 13 Jul 2006, ara.t.howard@noaa.gov wrote:

> On Thu, 13 Jul 2006 dblack@wobblini.net wrote:
>
>> Hi --
>> 
>> On Thu, 13 Jul 2006, ara.t.howard@noaa.gov wrote:
>> 
>>> On Thu, 13 Jul 2006 dblack@wobblini.net wrote:
>>> 
>>>> OK, but how do you know whether or not this is valid?
>>>>
>>>>  3:ab23:cat
>>> 
>>> it is valid.
>> 
>> I guess what I mean is: how do you know whether it's valid by
>> coincidence but actually wrong?
>
> the same way ruby knows that this
>
>  a = false and must_call_this_function_but_do_not!
>
> is valid but actually wrong -- it doesn't!  that's why logic errors are the
> worst kind to debug...
>
> fortunately for us too - otherwise we programmers would be out of work!

I think what I'm groping toward (or not) is a case where backtracking
is necessary before the conclusion is drawn that it's invalid.  I know
backtracking wasn't specified... but I wonder whether there are cases
that can't be resolved otherwise.  (Just thinking out loud, so to
speak.)


David

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