[python-uk] Tell us what you did with Python this year....

Doug Winter doug.winter at isotoma.com
Mon Dec 20 19:29:01 CET 2010

On 20/12/10 17:53, Alec Battles wrote:
>>> I seem to remember that 'file' in Linux detects encodings, but it's
>>> also a matter of calling it by the exact same name...
>> There is no foolproof way of detecting encoding unfortunately - you just
>> need to know what it is before you read the file.
> That's interesting. I wonder if there's a mathematical proof of the
> 'undecidability' of text encodings.

Hofstadter describes the problem in Godel, Escher, Bach as the "Envelope 
Problem" IIRC - you need to have some idea of how to decode any message 
you are sent, and you even need to understand that it is a "message".

UNIX manages the latter for us by providing a filename - but how to 
interpret the contents is entirely up to you.  It might be UTF-8, it 
might be a jpeg, it might be encrypted using AES.  You need to know what 
to expect to try and interpret the contents.

I bet there is a name for this (although probably not a proof), but I 
don't know what it is ;)



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