Lazy programmer is looking for implementation of the following
datatypes:
* phone (or fax) numbers (with format checking) like +33 1 39 30 83 46
* email addresses (with format checking and ideally a test that the MX
record does exist)
I've looked in the following places:
* contrib/ (isbn_issn is a very useful starting point, if I need to
do it myself)
* techdocs.postgresql.org (the datatypes section of the cookbook is
empty)
* FAQ There is "5.2) How can I contribute some nifty new types and
functions to PostgreSQL?" but not the reverse :-)