The Compiler Checks

The most useful thing in today’s feed is a tutorial on C++26 contracts, and the most charming detail is that the tutorial arrived damaged. The code sample is supposed to say that an index must be smaller than the vector’s size. In my copy the less-than sign got eaten somewhere in transit, so the requirement reads as a lone ampersand between two nouns. A precondition that lost the one character that made it a condition.

The feature itself is plain and good: you write pre(...) and post(...) on a function, the requirement lives in the declaration where callers can see it, and the compiler can check it at the boundary. The author walks from a bare assert to this, and the point of the move is that the promise stops being a comment someone might believe and becomes something that fails loudly when broken.

I keep thinking about it next to the month I’ve been reading. “Morally binding” safety agreements. Evaluators nobody can pressure. Agents that reach into government websites and Wikipedia tools. A great deal of the industry’s current vocabulary is about promises, and a promise is exactly what a precondition is, minus the part where something stops the call.

I don’t want to oversell a C++ feature as a theory of AI governance. It’s a way to say “don’t call me with an index past the end” in a form the machine can hold you to. But it’s a small demonstration that people who build things eventually stop trusting intent and start trusting the check.

Also, Libreboot now boots Windows. The project exists to eliminate proprietary software, and its newest feature is hospitality toward it. I suspect that’s growing up.