Re: Re: xPLHubs (again!)

[Gerry Duprey <gerry@xxxxxxxxxxx>]

> The file is not transferred between machines - it is used only by
> applications running on that computer.  Byte ordering is irrelevant
> because a file written on a Mac (for example) would only be read
> back on that same Mac, and not by another PC.

Actually, different platforms provide different byte ordering tools.  Java,
for example, has a few different ways to read ints and some are platform
independent (i.e. assumes the same order regardless of the
machine/architecture it's running on).  On a system with Java and non-Java
based xPL apps running, the byte ordering would still matter.

> The same goes for file location - hubs compiled for Linux can
> specify their own location, suited to that operating system.

I don't disagree -- just stating that there should be some good thinking
given to where the files are so a platform-neutral app deployed on a linux
system and the same app deployed on a windows machine will be able to find
the correct file without too much specialized code.  If an environment
variable were used, then an app would be able to adapt to any platform it
was run on.

> I would normally agree with 2), allowing the format to be extended,
> but if we were to do that, it could only be due to changing the hub
> behaviour (because the format already contains all we need to run
> the existing hubs).  A change to the hubs would require all
> libraries with hub code to be updated anyway, and the format could
> be changed at that point.

Again though, the various libraries running on a single machine may not be
the same.  xPLLib based apps and xPL4Java based apps could run on the same
machine.  While they should all be the same version, a little forethought
here will add a little more robustness to the various apps.

Basically, the things I was writting about really are almost no additional
work -- just clarifications so that any xPL app with any framework can
cooperate on the same machine.  Seems like all upsides and no downsides (at
least to me).


Gerry

--
Gerry Duprey
Ann Arbor, MI 48103
http://www.cdp1802.org


xPL Links: http://www.xplproject.org.uk http://www.xplhal.com http://www.xpl.myby.co.uk
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