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Jonathan Robie wrote:
> But I don't yet understand how the presence of a datatype can make reuse more
> difficult - except, perhaps, by requiring a cast. Can you help me with a
> concrete example or two?
Jonathan, I think you know that this question is ignoring my larger query--the
point which IMHO goes to the heart of what you are asking--which is whether
datatypes inhere in the representation of data (or in something like the terms
of Uche's article, whether class is intrinsic (the divine right of kings?)).
Nevertheless, since you ask for angle brackets, here is a snippet from my
morning's work:
<PLO021204>
<C37042GHW9>S5M</C37042GHW9>
</PLO021204>
This is actually an order to sell $5000 face of some notes. You'll have to
forgive the ugly *ML, but it's a genuine sample of what comes in to me from the
wild. If this were decorated with datatypes, those would presumably have to be
the datatypes expected by the process for which this documents is
'intended'--the process which will handle it as an order. Such datatyping would
essentially see the point of this document revolving around a USD$5000 face
amount on the sell side. However, the contractor for whom I am handling this
document cares only that this is one part of a larger order ('PLO') in the
day's trading. That contractor's job is to keep track of how many PLO pieces
are processed for each order in a given day--and the definition of what is a
given order depends on how many pieces there are. The process operated by that
contractor is specialized for, and understands only how to aggregate the pieces
into an order, and what the definition of an order is, based on how the
(potential) pieces of it are actually handled in the course of a day's trading.
The software which will be used against this document understands *nothing* of
the document's content, as that content would be understood in datatyping it
for processing this document as an order. This means that you are asking my
contractor to implement an understanding of order content--as opposed to order
form--in his software, just so that he will be able to understand the
datatyping of content, in order ultimately to know that such content, datatyped
or not, is of no use to him and will be thrown away unused. In other words, you
want me to demand an understanding in my software of what by definition of its
function it will never use. Yes, that is making my life, and my
contractor's--far more difficult and, yes, it is utterly unnecessary to impose
that burden and, no, the problem you insist on creating cannot be solved with a
simple cast.
Respectfully,
Walter Perry
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