json_array_elements_text?

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-array suggest using trim, and this does work:

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

Laurence