Bag

Bag by Ørjan Johansen is derived from John Conway's Fractran game/language, adding syntax and side effects to make it a "practical" programming language (although still an esoteric one), while being backwards compatible with it, and perhaps allowing a semi-efficient implementation.

The power, indeed Turing completeness of Fractran comes from viewing a natural number as the product of a bag (multiset) of prime factors, where the order of primes is immaterial but the number of each is important. The name of Bag is derived from this.

Author's note
Many details of the language are still under construction. There might even be a module system...

External resources

 * Author's Bag page, including original message to the esoteric language mailing list.