regexp strangeness

I'm using PostgreSQL 6.4.2 regexps, and they don't seem to work the way
I'm used to (Perl).

Here's the records in a simple table:

select * from t5 where name ~ 'bar';
name
--------
bar
abar
xbar
not abar
(4 rows)

I'd like to match the ones that begin with 'bar' or 'abar'.

select * from t5 where name ~ '^a?bar';
name
----
abar
(1 row)

select * from t5 where name ~ '^bar|^abar';
name
----
(0 rows)

Neither of these works. I looked at
pgsql/src/backend/regex/re_format.7, and it claims that ^, ?, and | all
work as expected. The type of name is varchar(30), in case that is
relevant.

Am I misunderstanding PostgreSQL's use of regexps, or is this a bug
others have seen?

Thanks for your help.

Andrew Merrill