[pmwiki-users] Re: Properties

chr at home.se chr at home.se
Wed Dec 14 13:15:27 CST 2005


On Wed, 14 Dec 2005, Patrick R. Michaud wrote:

> >   It seems hard to remember if something is a variable, a property, a
> > saved property or an attribute, and what are the different behaviours
> > of each, and do they need to be that way?  Accessibility outside of a
> > page (scope?), provided by pmwiki (constants?), author alterable,
> > searchable, available to conditions, page invariant (constants?),
> > ...very confusing.
> 
> Yes, and for a variety of reasons we need to be able to support
> *all* of the above behaviors and restrictions, so unification 
> is going to be a bit tricky.

For what it's worth, VHDL defines both "signals" and "variables". Both
types can have a varying value (i.e. they are not "constants"), but a
signal retains its history.

I'm guessing 'properties' would retain their history, whereas 'attributes' 
don't? 

Anyway, I haven't followed this thread very closely... it seems a bit 
confusing :-)

/Christian

PS. As an aside. A signal assignment is only "there" at the next time
instant. Comparing this with wiki pages, we might implement it as saying
that it's value is only changed *after* a page is shown (or saved).

Anyway... maybe it'd be a good idea to illustrate why (and for what) we 
need all these things...

-- 
Christian Ridderström, +46-8-768 39 44               http://www.md.kth.se/~chr






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