Yeah, I didn't even really register his prediction because I'm used to taking such statements with piles of salt.
Without a clear niche and "killer app", most languages don't have any way to draw attention or attract new programmers. I've run across Julia before, but never had a reason to look at it for more than a few seconds. Today I looked at it long enough to read half of the metaprogramming page, and file it away for potential future use if I need an array-oriented language or have a data science project, just for fun.
But most people won't hear about it, and won't have the same tendencies I do to try doing new projects in new languages. Perhaps Julia does have a specific problem it's trying to solve, and people with that problem are more likely to discover and adopt it, but that doesn't translate to the broader community very quickly.
> I'm bootstrapping from machine code not to keep things fast but to control the total implementation stack and so keep it comprehensible.
Yes, and I think you've made that point fairly well, but this was a fairly helpful clarification and restatement. Perhaps there are several dimensions to "exposed internals": visibility, accessibility (that is, manipulatability), and comprehensibility or traceability. And I think attempting to maximize these attributes will lead to a design much like you have in Mu of minimizing the overall surface area of the internals - otherwise they may start to obscure each other. Traceability at least is facilitated by shorter traces; that is, fewer layers of abstractions to navigate.
It seems that formal systems often follow an axiomatic model, parsimoniously adding layers as necessary, while industrial systems are more of the 'large, flat' model that build on top of an existing platform but don't add more than a few layers of abstraction. Generally just classes, interfaces, and service APIs. At the same time, the formal systems don't necessarily add true "layers", because identities are preserved across abstractions. Something to ponder more I guess.
Also, regarding performance, I'm not really sure how merely seeing the assembly code output by Julia helps that much if you can't directly control it. I could see it being helpful for sanity checks, or for learning about how the machine works (that's why I thought it was relevant), but it would be really hard to use for tuning.
> Do you know if building the Julia compiler relies on a previous version of the Julia compiler?
I don't know for certain, but it looks like the src directory contains a lot of CPP and some "flisp", so I would guess not.
