Hm... now that doesn't look all that consistent to me (after applying
the patch):
=# select ts_debug('simple', 'a...@123-yyy.zzz');
ts_debug
---------------------------------------------------------------------------
(email,"Email address",a...@123-yyy.zzz,{simple},simple,{a...@123-yyy.zzz})
(1 row)
But:
=# select ts_debug('simple', 'aaa@123_yyy.zzz');
ts_debug
---------------------------------------------------------
(asciiword,"Word, all ASCII",aaa,{simple},simple,{aaa})
(blank,"Space symbols",@,{},,)
(uint,"Unsigned integer",123,{simple},simple,{123})
(blank,"Space symbols",_,{},,)
(host,Host,yyy.zzz,{simple},simple,{yyy.zzz})
(5 rows)
One can also see that if we only keep the domain name, the result is
similar:
=# select ts_debug('simple', '123-yyy.zzz');
ts_debug
-------------------------------------------------------
(host,Host,123-yyy.zzz,{simple},simple,{123-yyy.zzz})
(1 row)
=# select ts_debug('simple', '123_yyy.zzz');
ts_debug
-----------------------------------------------------
(uint,"Unsigned integer",123,{simple},simple,{123})
(blank,"Space symbols",_,{},,)
(host,Host,yyy.zzz,{simple},simple,{yyy.zzz})
(3 rows)
But, this only has to do with 123 being recognized as a number, not with
the underscore:
=# select ts_debug('simple', 'abc_yyy.zzz');
ts_debug
-------------------------------------------------------
(host,Host,abc_yyy.zzz,{simple},simple,{abc_yyy.zzz})
(1 row)
=# select ts_debug('simple', '1abc_yyy.zzz');
ts_debug
-------------------------------------------------------
(host,Host,1abc_yyy.zzz,{simple},simple,{1abc_yyy.zzz})
(1 row)
In fact, the 123-yyy.zzz domain is not valid either according to the RFC
(subdomain can't start with a digit), but since we already allow it,
should we not allow 123_yyy.zzz to be recognized as a Host? Then why
not recognize aaa@123_yyy.zzz as an email address?
Another option is to prohibit underscore in recognized host names, but
this has more breakage potential IMO.
--
Alex
