BUG #6375: tsearch does not recognize all valid emails

The following bug has been logged on the website:

Bug reference: 6375
Logged by: Valentine Gogichashvili
Email address: valgog(at)gmail(dot)com
PostgreSQL version: 9.1.1
Operating system: Debian 4.4.5-8
Description:

Hello,

default tsearch parser does not recognize all valid email addresses and
tokenizes them as text, splitting into tokens.

For example:

postgres=# select to_tsquery('simple', 'normal(at)email(dot)com' );
to_tsquery
────────────────────
'normal(at)email(dot)com'
(1 row)

here it behaves ok;

postgres=# select to_tsquery('simple', '-still-normal(at)email(dot)com' );
to_tsquery
──────────────────────────
'still-normal(at)email(dot)com'
(1 row)

here it trims '-' from the beginning of an email. This is not correct, but
will at least find that email.

postgres=# select to_tsquery('simple', '-not-normal-with-dash-(at)email(dot)com'
);
to_tsquery

───────────────────────────────────────────────────────────────────────────────
'not-normal-with-dash' & 'not' & 'normal' & 'with' & 'dash' & 'email.com'
(1 row)

and this is now a real problem as it leads to finding emails that are not
the same, but are "super-sets" of that one.

Valid email characters, that are not correctly treated also are at least '+'
and '.'

With my best regards,

-- Valentine Gogichashvili