Consider changing the name of the package?

[cyberglot]

LVar is a thing that already exists and even though your package seems fairly related, LVars have precise semantics. It would be nicer if we could avoid confusion among all our vars.

[srid]

Ah, I didn't know that something else was already using the Data.LVar namespace.

Sure, let's change it. I would like to have something that is shortish and easy to remember, which is why I avoided names like TMVarL or TMLVar.

What about SVar (as subscribe-able)? Will have to look at other possibilities ...

EDIT: Or maybe TLVar, as a compromise.

EDIT(note to self): Pick a suitable name $foo, so that addon packages can be named appropriately, eg: $foo-filesystem for fsnotify based "mounting" on to LVar (or don't bother with this, and choose say fsmount as the package that uses tlvar package).

[ju1m]

@srid, your LVar looks rather like a special case (the TMVar case) of push-based reactive values.
For comparison, here's some other (more or less well implemented, more or less thread-safe) variants of reactive values:

• In keera-hails-reactivevalues, see especially the "Chapter 7. Use Case: Reactive Values" in Iván Pérez's thesis. See also Keera Studios' tutorial on reactive values.
  That's the simplest implementation I've seen, even though the interface is a bit convoluted, names too longs (eg. ReactiveFieldRead/ReactiveFieldWrite/ReactiveFieldReadWrite could just be RO/WO/RW), and would deserve an update to use modern features in GHC, like DuplicateRecordFields, OverloadedRecordDot and HasField, instead of using ad hoc classes like ReactiveValueRead/ReactiveValueWrite/ReactiveValueReadWrite.)
• In reactive-banana, notice how the notification uses Map's foldMap instead of mapM_ or forM_ to decrease the number of allocations.
• In arpeggigon's MCBMVar, based-upon keera-hails-reactivevalues but add support unregistering callbacks.
• In fay-base, which targets Javascript.
• In reactive, too complicated for me.

Anyway, just to attach some context around your LVar in case that might help naming it, or improve the interface.

EDIT: There's also transient's EVar.