Design
These pages are designs for things slate has not got yet, written before the work so that the decisions are argued once and in one place. Nothing here describes the compiler as it stands today.
Their programs are not run. Every other page under docs/ is executed by the test suite, which is
what makes it trustworthy; a design page shows syntax that does not compile yet, so its blocks carry no
language tag and the harness reads none of them. A page is rewritten as a
reference page when the thing it describes is built, and the design page goes.
| Actors | parallelism: one thread, one heap and one loop per actor, and messages that are copied |