Store and index YAML with PostgreSQL, with Javascript lib or reusable functions?

Question

PostgreSQL 9.2 has native JSON support. I'd like to store human readable config files, however, in YAML. And I think I'd like to index a few (but not all) of the config file values. Therefore I'm wondering:

1. Is it's somehow possible to include [a third party Javascript library that parses Yaml] in Postgres, for example js-yaml. Then I could have my own YAML Javascript helper, in the same way as there's the built-in JSON helper in PostgreSQL 9.2.

Alternatively:

1. is it possible to declare individual reusable Javascript functions? If so, then I could add my own YAML parsing functions (based on simple regexps), that are able to parse a subset of YAML, for example the top level key-value pairs here:

   # some "top level key-value paris":
   the_key: 'the value'
   another_key: 'another value'
   # But this however:
   would_be_too_complicated_to_parse_manually_with_regexps: |
     block string
     with newlines
   

Worst case scenario would be that I'd need to duplicate YAML parsing code in each PostgreSQL stored procedure (if I cannot add 3rd party libraries or declare reusable functions).

(Performance wouldn't be terribly important in my case.)

(I've googled a while for "postgresql plv8 reusable function" and "postgresql plv8 library" but found nothing of relevance)

Answer 1

The pl/v8 procedural language is probably the way to go. It's a 'trusted' language, which means (among other things) it does not provide any way to do the 'load an external module from this file' thing. But it does have a 'find_function()' method to let you define your own javascript function and call it from another function (js or not). See description of it in this blog post:
http://umitanuki.hatenablog.com/entry/2012/04/10/171935