mark++

The essence of JIT is that it defers a substantial portion of compile-time to run-time. In a JIT scenario, we generate machine code just-in-time to execute it.

Now consider “scripting” languages like Perl, Python, Ruby, etc. These guys don’t even bother parsing ahead of time. My 2+ GHz processor hardly breaks a sweat.

OK lets review:

1. Programming is hard
2. Good design is difficult
3. Optimization sucks
4. Processor cycles are free

Clearly, if I can spend processor cycles to make programming easier, it’s worth it.

So why am I blathering on about this? Well, I thought there was nothing left for us to usefully push into run-time. I was wrong: we can still combine edit-time and run-time. Check out the Subtext programming language and this cool demo.