Richard Newman » holygoat.co.uk

Wed 16 Feb 2005

Snippets

Some of the things I've seen this evening:

Very true:
Can you imagine Apple issuing a fix like: “In the Open box, type ‘Regsvr32 urlmon.dll’?”
I've seen a couple of links to this Nina Gordon cover of NWA's Straight Outta Compton. It's amazing, really.
A bit of justified bitching about iPhoto's awful keywords system.
FilmTrust, the latest thing out of Jen Golbeck and the rest of the Mindswap crew at Maryland. A social software site that's actually useful, and outputs really great FOAF.

Posted at 2005-02-16 14:46:02 by Richard • Link to Snippets
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Little Wilbur addon

As today is a “hacking day” I'm actually producing some useful code. The following is a little pair of recursive functions to turn a Lisp list into an rdf:List; i.e., (!ex:elem1 !ex:elem2 !ex:elem3) into

ex:listElem rdf:first ex:elem1; rdf:rest
  [ rdf:first ex:elem2; rdf:rest
    [ rdf:first ex:elem3; rdf:rest rdf:nil ] ] .

This adds directly into a Wilbur store.

`node-or-bnode`

If n is nil, returns a new bnode. Otherwise, n.

(defun node-or-bnode (n)
  (if n n (node nil)))

`add-list-triples`

Adds an rdf:List element to the database, returning the node. If list-node is provided, use that as the element; otherwise, a new bnode is created.

(defun add-list-triples (database 
                         first-elem rest-elem 
                         &optional list-node)
  (let ((sub (node-or-bnode list-node)))
    (db-add-triple database
	  (triple sub !rdf:first first-elem))
    (db-add-triple database
	  (triple sub !rdf:rest rest-elem))
    sub))

`list->rdf-list`

Convert a Lisp list into RDF triples, adding to database. list-node is an optional node to use as the root of the list.

(defun list->rdf-list (database elems 
                       &optional list-node)
  (if elems
    (add-list-triples database 
      (car elems) 
      (list->rdf-list database (cdr elems)) 
      list-node)
    !rdf:nil))

I hope someone else finds these useful! Maybe it'll make rdf:List a bit easier to work with… alternatively, if someone rewrites these to not be rubbish, do let me know!

Posted at 2005-02-16 06:35:17 by Richard • Link to Little Wilbur addo…
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