Comment by guenthert
2 years ago
> The sad part is that it was impossible to get anybody else working on it and I had to rewrite it in Java (and destroy performance in the process).
Java has a CFFI and while it ain't pretty, I don't see where the performance impact would come from, when machine code is to be injected and the critical path is in machine code / C.
> extremely low level (like understand what the CPU does when it gets an instruction) as well as the highest level (complex abstractions with Lisp macros, etc.)
Those skills don't seem all that far apart. I'd rather think it'll be difficult to find someone willing/able to encode and maintain financial / legal safety limits in machine code :-}
I can't speak for onetimeuse92304, but it's probably because the program which generates machine code was in Common Lisp and SBCL using the techniques FTA, and it would basically be impossible to port in any reasonable way. Experimenting with and deploying assembly code generation in SBCL is very organized and flexible—much better in Lisp than in C even.
Technically, you can write a compiler in any programming language. So yeah, you can do it in Java, too. But why if Lisp already has a compiler built in that you can use for the advantage. That's pretty much the idea.
I also happen to know Java (almost 20 years of experience with it).
The point of rewriting it to Java wasn't just the Common Lisp. Compiling and injecting code into high throughput, live, mission critical application proved to be too much of a challenge for developers we tried to hire. Even if I rewrote this for Java (which I absolutely had no intention of doing) the problem would still persist. Most Java devs have even worse understanding of the low level operations than Common Lisp.