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I am building an analog to pipes-concurrency (purescript-pipes-aff), and I am looking for a solution to buffer messages for the producer to read from. Currently bus just gives me a single message and I have to be fast not to miss it. I am wondering what would be involved (and if this would be the right place for this) to buffer a configurable amount of messages with configurable behavior. What I like and appreciate about purescript-aff-bus is the notable absence of FFI calls, leaving that entirely to the purescript-aff library and I think the buffer implementations could and should be implemented similarly. For reference, this is how it's implemented in haskell: https://github.com/Gabriel439/Haskell-Pipes-Concurrency-Library/blob/fccb359dbfb2988da83166d4e2bc6ff01dbe986d/src/Pipes/Concurrent.hs#L177-L198. Any input would be greatly appreciated.

Would be nice if we could avoid the delay before the kill

https://github.com/slamdata/purescript-aff-bus/blob/e57663b133864fc34ed29989f850c7b6a05c2052/test/Main.purs#L60-L63

Note there is a typo interpats should be interrupts

Hi,

noticed that Aff-Bus is leaking slowly memory in a toy project i have. Here is a minimal working example which shows the leakage quite well (on my machine after 30sec 500MB and rising):

loopy :: BusRW Unit -> Aff _ Unit
loopy bus = do
  _ <- Bus.read bus
  _ <- forkAff $ loopy bus
  Bus.write unit bus
  
main :: forall e. Eff _ Unit
main = launchAff_ $ do
  bus <- Bus.make
  _ <- forkAff $ loopy bus
  Bus.write unit bus

I have only tested this with node (v8.11.1) not in a browser.

After playing around a bit, i noticed that the problem seems to be the traverse with Either here https://github.com/slamdata/purescript-aff-bus/blob/master/src/Control/Monad/Aff/Bus.purs#L64

Replacing the traverse with pattern-matching seems to fix the problem e.g.

attempt (takeVar cell) >>= case _ of
    Left _ -> pure unit
    Right res -> do ....

Can anyone confirm the leakage? Is this even a problem in Aff-Bus or is it Aff making problems?

Comment on #6:

This might need to be an unsafe fork (liftEff <<< launchAff) unless you want to let users to control the lifecycle of the loop with supervised.

Based on the logs https://travis-ci.org/slamdata/purescript-aff-bus/builds/343317545#L1237

As I understand that after Bus.kill, execution of Aff stops and never reaches the assertion and log "ok"

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As described in the documentation section of the Library Guidelines, Contributors libraries are expected to have in their README a short summary of the library's purpose, installation instructions, a quick start with a minimal usage example, and links to the documentation and contributing guide.

This library currently doesn't have a completed quick start in the README.

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The library needs a quick start section after the installation instructions. argonaut-codecs is one example of a library with a quick start.

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Is your change request related to a problem? Please describe.
As described in the documentation section of the Library Guidelines, Contributors libraries are expected to have mostly complete module documentation, preferably uploaded to Pursuit.

This library currently doesn't have sufficient module documentation -- several publicly-exported types have no documentation at all.

Describe the solution you'd like
These types all need documentation:

Once updated, we should tag a release and upload new module documentation to Pursuit so that folks can use it.

Additional context
See the Governance repository for more information about requirements in the Contributors organization.

In some cases you might wanna allow "reader" (read :: Cap) to be able to kill a bus too.

I'm thinking on something like:

• add type BusRK = BusR' (kill :: Cap)
• add split' ∷ ∀ a. BusRW a → Tuple (BusRK a) (BusW a).
• changing kill ∷ ∀ eff a r. CanKill r => Exn.Error → Bus r a → Aff (avar ∷ AVAR | eff) Unit, this CanKill instance will be available for write :: Cap or kill :: Cap