Some of the things that Clojure generates are valid bytecode for which there is no Java source code equivalent.
Reusing the pieces:
In general, Clojure works so well because it is all of a piece, with many decisions and subsystems working together. Datomic's source is the same way, you can't really consume just part of the elephant, even if you had the source code. Many things that Datomic does simply don't make sense at all out of context.
Although it is true that "time traveling" queries are relatively rare for production needs, the basic architecture supports things that many applications really need:
- It is possible to make queries against the database PLUS additional data not yet added, that is, "what if" queries
- Having a stable database-as-value is really useful for paginating results; you don't have to worry about new values being inserted into your results during execution, the way you do with traditional databases no longer how long (minutes, hours, even days) you take to traverse the data
- Reified transactions makes it possible to store extra data with each transaction, trivially, such as who made the update and why
- Immutability is amazing for caching at all layers
That would be very ugly source, as Datomic is written in Clojure and AOT compiled to Java bytecode. Due to the architecture of Clojure (especially, the use of macros) it is not exactly possible to work backwards from JVM bytecode to anything that looks like the original source code. It's not like Java where a clever decompiler can exploit output patterns generated by the Java compiler to make reasonable guesses at the structure of the source code.
But this is all besides the point; Datomic is now free (as in beer) with a great license (Apache 2.0). You can use this amazing tool for free, and you have as much need to look at the source to do so as you might need to look at PostgreSQL's source.
Some of us have been hoping for this day since Datomic was first announced, but even as an insider (I have been working at NuBank NA for less than a year) I was stunned at the speed with which this decision was made and implemented.
A long, long, long, time ago I had a conversation with a Unix consultant at my Dad's business; his hobby was flying stunt planes with a twist: each plane had a 100 yard long ribbon tied to the tail; the winner was the pilot who landed with the longest tail.
This would be a terrific non-violent flight combat game; you could imagine with modern graphics and even VR it could be very satisfying.
Further, the consultant lost his license for a couple of years when he evaded an opponent by illegally flying under a highway overpass and a passer-by reported his plane's ID to the FAA; that could be a mechanic itself, extra risky maneuvers that had a chance of some big negative effect.
Some of the things that Clojure generates are valid bytecode for which there is no Java source code equivalent.
Reusing the pieces:
In general, Clojure works so well because it is all of a piece, with many decisions and subsystems working together. Datomic's source is the same way, you can't really consume just part of the elephant, even if you had the source code. Many things that Datomic does simply don't make sense at all out of context.