Re: [Plastic-devs] Select or show colums message

[Mark T. <m.b...@br...>]

On Thu, 20 Jul 2006, John Taylor wrote:

> Thinking again about this, I have an idea that might allow us to combine 
> the increased "pluggability" of having a generic message with the 
> control implied by a more specific one and thus keep both you and 
> Richard happy.
> 
> If we think of a generic selectCols(id, cols[]) message as just implying 
> "here are a bunch of columns, do with them what you will", then we need 
> a way of the recipient stating what it is able to do with the message, 
> and the sender choosing amongst the options.   We could do this by 
> decorating the message with the extra information.   URI fragments are a 
> natural way to do this, since (IIRC) the fragment is intended to be 
> interpreted by the client (the recipient of the message in this case).

  ...

> Comments?

John, unless there's some subtle gotcha that hasn't occurred to me yet, 
I call that brilliant thinking.  It's the message receiver, not the
sender which is able to give specifics on what the effect of a 
generic message will be, and trying to tackle it the other way
round by defining a load of disjoint messages which cover all the
things that a client might want to do with data is doomed to 
not working very well.  Top marks for spotting this and working out
what to do about it.  I am in full agreement with your proposal.

Mark

-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b...@br... +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/