Allow SQL/plpgsql functions to accept record

Is there a fundamental reason SQL/plpgsql functions won't accept record 
as an input type? If not, can someone point me at a patch that might 
show how much work would be involved in adding support?

My particular use case is a generic function that will count how many 
fields in a record are NULL. I can do it in pure SQL (below), but was 
hoping to wrap the entire thing in a function. Right now, I have to add 
a call to row_to_json() to the function call.

SELECT count(*)  FROM json_each_text( row_to_json($1) ) a  WHERE value IS NULL
-- 
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com