LibtaskExt: state needs to include (1) VarInfo, (2) a boolean indicating whether to resample

[penelopeysm]

AdvancedPS.jl/ext/AdvancedPSLibtaskExt.jl

Lines 19 to 26 in 3cb7ec8

	# In Libtask.TapedTask.taped_globals, this extension sometimes needs to store an RNG,
	# and sometimes both an RNG and other information. In Turing.jl the other information
	# is a VarInfo. This struct puts those in a single struct. Note the abstract type of
	# the second field. This is okay, because `get_taped_globals` needs a type assertion anyway.
	struct TapedGlobals{RngType}
	rng::RngType
	other::Any
	end

Right now the other field only stores a VarInfo. By coincidence (okay, historical design), the varinfo also contains a flag called "del" which says whether we need to resample or not (i.e. whether it's the reference particle or not).

We want to get rid of "del" from varinfo. To do so though we need to have an equivalent source of information for Turing to pick up on and thus this other field probably needs to be a tuple of Bool + AbstractVarInfo.

[penelopeysm]

Ohh, I just realised this actually doesn't need any actual source code changes to AdvancedPS, so maybe the only thing that needs to be updated is the comment 😄