masak
Introduce a runtime environment
I think in practice, it will be very similar to the globals, and something we load right after the globals.
err should go there; according to bellanguage.txt, that's the right place for it. (Edit: #217 disagrees — though I must say the evidence is a little inconclusive.) (Edit edit: No, back to believing it should be a global, "supplied by the runtime environment".)
PicoLisp also has a bye function; it should go there too.
Maybe other things also deserve to go there, such as things having to do with debugging (#52) and the REPL itself.
Another candidate for this is to have a (breakpoint) function. Python has the prior art. Maybe we should call it (bp) to better align with Bel's own penchant for brevity.