Unfortunately we missed Postgres Open this year, but we did catch some of the slides. One of them was Embracing the web with JSON and PLV8 by Will Leinweber of Heroku. He had a great slide deck with a lot of interesting points. One surprising for us was that even in tasks that both PL/PgSQL and PL/V8 can do, PL/V8 is sometimes faster as demonstrated in his slides:
#51 thru #54
In one article we demonstrated a JQuery app with PLV8 and one of JQuery's foundations is the CSS like selector syntax it provides for JSON and HTML document elements which allows you to drill down a document using CSS3 style referencing, much like what xpath does for xml. One of the glaring features missing in PostgreSQL 9.2 basic JSON support is a function to navigate a JSON document comparable to the PostgreSQL built-in xpath function for xml.
So how do we get this json selector goodness available to us in the database? Like all good monkeys, we copy/emulate it.