On Wed, Jun 12, 2013 at 11:38 PM, Merlin Moncure <mmonc...@gmail.com> wrote:
> no argument against json_typeof, but why can you just peek the first > non-whitespace character? json is famously easy to parse (see here: > http://www.json.org/) > > create or replace function json_typeof(_json json) returns text as > $$ > select case substring(ltrim($1::text), 1, 1) > when '[' then 'array' > when '{' then 'object' > end; > $$ language sql immutable; > > you could expand this mechanic fairly easy to cover all json types. > note exception handlers are very heavy for this type of operation. Thanks for the suggestion -- hadn't thought of just looking at the first non-whitespace character. It should be trivial to make this into an efficient C function that could live in jsonfuncs.c as a built-in. I might do that and submit a patch for 9.4 CF2. Cheers, -Andrew
