BUG #4207: EXTRACT function

The following bug has been logged online:

Bug reference: 4207
Logged by: Jeferson Kasper
Email address: jefersonkasper(at)gmail(dot)com
PostgreSQL version: 8.1.5
Operating system: Windows XP and Linux Redhat
Description: EXTRACT function
Details:

Hello.
First... sorry for poor english :)
My problem is quite simple.
the EXTRACT(field FROM source) function allows to use some kind of 'fields',
and i need to know if a time (like '07:00') is after the midday(12:00) or
not.
I know i can resolve it implementing some function like "select
('07:00'<'12:00')".. i just want to know if is difficult to implement a new
field called 'am', to use like.

select extract(AM from '07:00');

?column?
--------
t

i hope its not difficult, and i should use it, if it become available ...

Thanks for all.