[Jsdsi-users] Tag problem

[Sean R. <sra...@ae...>]

Sameer,

Did you have any thoughts on how I could implement my 'FilepathTag'
problem that I mentioned last week better using standard jsdsi tag
types?


Regards,

Sean

P.S. I hope to run my junit tests againgst the latest CVS code this w/e.


> > 2. Added a new Tag type (FilepathTag which is to specify a
Principal's
> > access rights to a file hierarchy)
> 
> Shouldn't this just be a combination of SimpleTags, SetTags, and
> PrefixTags?  For example:
> (file-access (*set read execute) (*prefix /home/ajmani))
> would grant read and execute permision on any files under my home
> directory.

One would think so. However at the time there were some issues in doing
this for the particular application (which is a bit of a playground
app)... The one I can think of at present is:

(file-access read /home/ajmani/ant/)
implies
(file-access read /home/ajmani/) and
(file-access read /home/) etc
but does not imply
(file-access read /home/ajmani/ant/bear)

whereas

(file-access admin /home/ajmani/ant/)
does not imply
(file-access admin /home/ajmani/) or
(file-access admin /home/) etc
but does imply
(file-access admin /home/ajmani/ant/bear)

I can see that one could model the 'admin' version using a PrefixTag for
the path element, but one as far as I can see one would need some form
of SuffixTag (ReversePrefixTag) for the 'read' version.

Can you see a way of doing it better?


-- 
Dr. Sean Radford, MBBS, MSc
sra...@ae...