[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: RFC: ppath(3): property list paths library
On Wed, Nov 03, 2010 at 05:57:39AM +0000, David Holland wrote:
> On Mon, Nov 01, 2010 at 08:00:09PM -0500, David Young wrote:
> > I'm working on a library called ppath(3) for making property lists more
> > convenient to use in the kernel. With ppath(3), you refer to a property
> > to read/write/delete in a property list by the path from the list's
> > outermost container. Comments welcome.
> Speaking from the POV of someone who's been working on querying
> semistructured data for several years now... I have a pile of
> high-level questions: (1) can you articulate the expressive power you
> intend for your path expressions, and why that's a logical stopping
> point vs. more expressive things;
I want to index individual elements in a property list using succinct
and reliable C code. Ideally, I would be able to treat a property
dictionary/array as a C struct/array and use an expression such as
It's a logical stopping point because it meets my needs.
(2) what if any facilities do you
> envision for checking paths against proplist schemas when/if we ever
> manage to sort out a system for that;
> (3) what model do you have for
> dealing with cases when the values found at the paths provided are not
> what the user is expecting; and
ppath(3) routines return EFTYPE if the application code tries to read
one type (e.g., bool) from a path and ppath(3) finds another (e.g.,
number) at that path. Beyond that, it's up to the application.
> (4) what model do you have for dealing
> with cases where the path does not name a single unique value or
> position, if that's possible?
That's not possible.
David Young OJC Technologies
dyoung%ojctech.com@localhost Urbana, IL * (217) 278-3933
Main Index |
Thread Index |