Everything below happens in this tab: the parser, the type checker, the
lowering and the VM are one WebAssembly module, and no source leaves the
browser. A task spawn is refused rather than emulated —
a Cove task is a thread and a worker has one.
Run & record runs the program under a debugger that
writes down what it saw, and the timeline below scrubs through it,
marking where you are in the editor itself: a worker cannot block
waiting for the page, so the machine is not stepped, it is recorded.
The editor is read-only while a recording is open, because the mark has
to point at the source that ran; End replay closes it
and gives the editor back. Pick a sample to see what the language looks like, or
write your own — the picker never replaces something you have changed
without asking, and nothing here is saved anywhere.