Re: datatypes and MT

At 06:55 PM 11/5/01 -0600, Pat Hayes wrote:

>>So, returning to my DTLS, DTVS, DTLV musings [1]:
>>
>>- Sometimes, we know/express a value in DTLS (the literal space) -- the 
>>case noted above.

(I meant to say "lexical space").


>>- Sometimes, we know that the value of some node is in DTVS (the value 
>>space) -- this corresponds to the view of data type as describing a value 
>>space (The view I think Brian is expressing).  Of itself, this doesn't 
>>help us express a particular value.
>
>No, but *together with the literal itself* it enables you to figure out 
>the value intended. It disambiguates the literal, if you like. That's all 
>it needs to do; the literal itself provides the particular value, once you 
>know how to interpret it.

Hmmm...  When you say "the literal itself", do you mean the lexical string?

(I've tried to use the terms "literal string" and "literal value" to 
distinguish the lexical and  value spaces, but I may have slipped in places.)

I think we agree, but I'd prefer to say that we need a mapping scheme (my 
DTLV) to express a given value as a string.  That provides your "once we 
know how to interpret it".

>>- Sometimes, we know a particular value in DTVS;  but to *express* this 
>>value, we need a corresponding value in DTLS
>
>But the literal itself IS the particular value in DTLS. We don't need 
>another name for it: we have it in our syntax already. We don't have to 
>even mention or refer to it at all; we just have to know how to interpret it.

I don't see how that's different from what I'm saying.

There is a number value that designates the number of fingers on both of my 
hands.  I understand that number on various ways, some not 
linguistic.  That is my value in DTVS.  I want to express that number in a 
text-based communication, so I need a lexical representation for 
it.  Commonly, I might use "10" and many people would understand how to 
interpret it.  An ancient Roman might have used "X".  An early computer 
programmer might have used "1010" or "12" or "A".  These are all different 
literal strings (in some DTLS or other).  I don't see these as inventing 
"another name":  they're lexical representations of the given number value 
under different mapping schemes (DTLV).

#g


------------------------------------------------------------
Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Tuesday, 6 November 2001 09:25:58 UTC