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Hi,
On Feb 24, 2006, at 3:41 PM, Bullard, Claude L ((Len)) wrote:
> It's like
> asking your mailman to do your taxes instead of moving the
> form to the IRS and bringing the payment back.
To extend the analogy:
There is your mailman and your tax consultant, both having a
processThis() method.
You send you tax stuff to the tax consultant because you know it is a
tax consultant and you send your mail to your mail man because you
know that it is a mailman.
But the give-stuff-to-operation is uniform ("take this and do what
your job is"), I do not have to know about a processMail() or
processTaxStuff() method.
If the mailman changes jobs and you still hand him your mail (say
because he happens to live in the same street now and passes by)
he'll be able to respond: "No, go away...that ain'y my business anymore"
Aside: the 'that' in the last sentence implies that the (former)
mailman understands your intent.
I wonder if it is sufficient for the receiver to infer the intent
from recognizing what the stuff is that you handed to him (e.g. looks
like mail => must be mail[1]) or if a protocol mechanism is needed
such as HTTP's Expect header.
If not, the out of band coordination (besides the protocol) would be
reduced to a shared (loose?) understanding of what mail is.
Thoughts welcome.
Jan
[1] Aka "Duck Typing":
http://www.propylon.com/news/ctoarticles/040224_duckmodeling.html
________________________________________________________________________
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Jan Algermissen, Consultant & Programmer
http://jalgermissen.com
Tugboat Consulting, 'Applying Web technology to enterprise IT'
http://www.tugboat.de
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