Dumping SQL type names

A while ago I suggested to create a backend internal function that takes
an internal type name and an atttypmod and formats it to a canonical SQL
type, to be used by pg_dump, psql, and anyone who feels like it.

I have it written now, here's an example of how it works. Any comments?

regression=# select c.relname, a.attname, format_type(t.typname, a.atttypmod)
from pg_class c, pg_attribute a, pg_type t
where c.oid=a.attrelid and t.oid=a.atttypid
and c.relname not like 'pg\_%' and a.attnum > 0
order by 1;

relname | attname | format_type
-------------------------+---------------+------------------------
a | aa | text
a_star | class | character(1)
a_star | aa | integer
a_star | a | text
abstime_tbl | f1 | abstime
aggtest | a | smallint
aggtest | b | real
arrtest | a | smallint[]
arrtest | b | integer[]
arrtest | c | name[]
arrtest | d | text[]
arrtest | e | double precision[]
arrtest | f | character(5)[]
arrtest | g | character varying(5)[]
b | aa | text
...

--
Peter Eisentraut Sernanders väg 10:115
peter_e(at)gmx(dot)net 75262 Uppsala
http://yi.org/peter-e/ Sweden