Returns true or false whatever the string given is a valid email or not

is_email.plpgsql.sql

CREATE OR REPLACE FUNCTION is_email(email VARCHAR) RETURNS BOOLEAN AS $$
BEGIN
  RETURN email ~* '^([^@s]+)@((?:[-a-z0-9]+.)+[a-z]{2,})$';
END;
$$ LANGUAGE plpgsql