From: Josef 'Jupp' SCHUGT <jupp@...>
Date: 2006-01-07T07:18:26+09:00
Subject: Re: Email Address Regex

Hi!

At Wed, 4 Jan 2006 21:47:34 +0900, Andreas S. wrote:

> It is trivial to create a formally correct address that makes
> absolutely no sense, so what's the point of doing such a complicated
> and error-prone validation?

To give one example: On German keyboards "@" is entered using
"AltGr-q". If one releases "AltGr" before pushing "q" (which may well
happen if you type the quick-and-dirty way) "nobody@example.com"
becomes "nobodyqexample.com".

Also one should keep in mind the three commandments of distrust:

1. He who inputs is guilty.

2. He who inputs remains guilty unless he proofs that he is *not*
   guilty.

3. If the proof under rule 2 leaves any doubt (no matter how tiny it
   may be) the first rule applies.

In short: Input is evil unless you know for sure that it is not.

Josef 'Jupp' Schugt
-- 
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gleichen Grunde umgehend zu entziehen.