todo.txt

- channel multiple in/out, FIFO
- IN, OUT, ALT if channel closed. Report errors. What to return on channel closure?
- correct error unwinding. report stack trace for the whole tree, error bubbling.
- ALT -> select
- pluto serialization
- lua checkstack everywhere
- catchterminate
- make it a module, non-invasive. Avoid LUAI_EXTRASPACE. how?

- TDD: runtime error must be test failure.
- lua variant for arguments (ref/unref is too slow). 
  Consider to use table with __gc instead of userdata. And put all the refs (ch+args) there.
  Use uservalue feature for userdata.
- userdata variant for C++ type checks.
- memory pools, HWMs.
- channel for in/out only (in/out qualifiers?)
- x64
- cmake
- 'defer' keyword.




ALT(
	ch1, function( arg1, arg2 )
	end
	,
	ch2, arg1, arg2, function()
	end
)

ALT(
	ch1, IN, function( arg1, arg2 )
	end
	,
	ch2, OUT, { arg1, arg2 }, function()
	end
)

ALT(
	ch1, function( arg1, arg2 )
	end
	,
	ch2, { arg1, arg2 }, function()
	end
)