Resent at Drummond's request as not everyone got it the first time.
Thanks Drummond! Glad to be on board.
How do the two roles of $is form a single coherent concept? Right now the modifier role (as a passive voice marker modifying the following verb) and the standalone role (as the copulative verb) seem like distinct definitions to me. I realize this is analogous to the English verb "to be" that also serves in both these roles, but is there a philosophical / semantic / formal (take your pick) argument that this should logically be the case in XDI?
One difference I notice between XDI terminology and linguistics terminology is that in the latter, "predicate" means verb together with object, not simply the verb.
On May 28, 2010, at 6:27 PM, Drummond Reed wrote:
Although I was not able to attend the last TC call, Giovanni and Joseph Boyle (our newest TC member -- welcome Joe!) still held a chat thread. On that thread, they discussed a line of the example PDX document that I posted to http://wiki.oasis-open.org/xdi/PdxExample last week.
The line was right near the start:
$ <-- Pattern: Context Self Descriptor -->
$is$a
($xdi$v$1) <-- Pattern: Context Type -->
($pdx$v$1)
$is($xdi$v$1) <-- Pattern: Context Authority -->
=!1111.aaaa.bbbb.cccc!9999.xxxx.yyyy.zzzz
They were discussing what the predicate "$is($xdi$v$1)" meant.
I thought this was fairly straightforward from the definition of $is as the universal XDI inverse predicate when used as a restriction on any other XDI predicate. Examples:
PREDICATE INVERSE
+father $is+father
+author $is$author
EXAMPLES
=gardner/+father/=drummond
=drummond/$is+father/=gardner
+davinci.code/+author/=dan.brown
=dan.brown/$is+author/+davinci.code
So, the statement
$
$is($xdi$v$1)
=drummond
...is the equivalent to saying
=drummond
($xdi$v$1)
$
..which is simply a way of sayiing that the current XDI context (XDI
