json_array_elements_text?

Hello,

I'm trying to unpack a json array into it's constituent text values so I
can join them to a table. I can successfully unpack json values, but am
having trouble converting these to text so I can cast them to the UUIDs
needed for the join.

http://dba.stackexchange.com/questions/54283/how-to-turn-json-array-into-postgres-arraysuggest
using trim, and this does work:

SELECT trim(json_array_elements(biosample.properties->'treatments')::text,
'"')::uuid
FROM object biosample WHERE biosample.item_type = 'biosample'

But it seems kinda ugly. Am I missing something obvious or is postgres 9.3
just missing a json_array_elements_text function?

Laurence