substring syntax with regexp

hi,

Does anybody know offhand what is the correct way to use substr to extract the domain name from a client_referer column as logged by mod_pgsqllog (httpd module), by correcting the following:

the file 'hostname.sql' is pl/pgsql

main=> \e hostname.sql
ERROR: syntax error at or near "http" at character 290
LINE 13: newuri = substr(tempuri from 'http://[^/]*/.*');
^
I don't know, the docs are:

The substring function with two parameters, substring(string from pattern), provides extraction of a substring that matches a POSIX regular expression pattern.

(http://www.postgresql.org/docs/current/static/functions-matching.html)

the full 'hostname.sql' as is now is:

CREATE or replace FUNCTION hostname() RETURNS setof logpgsql.stats_type as
'
declare
row stats_type%ROWTYPE;
rec record;
newurl varchar(100);
tempurl varchar(100);
begin
for rec in SELECT * from stats
loop
row.c = rec.c;
tempurl = rec.url;
newuri = substr(tempuri from 'http://[^/]*/.*');
row.uri = newurl;
row.r = rec.r;
return next row;
end loop;
return next row;
return;
end
'
LANGUAGE 'plpgsql';