Remember that bash's grammar is derived from the specification of the POSIX shell (http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html). Also, any addition to the bash grammar should be backwards compatible (or enabled with a shopt, disabled by default), to avoid breaking already working scripts.
Due to the complexity of the above limitations, I'd just use perl or another language. It's not worth the effort. So don't feel discouraged if you send patches and these are rejected.
