From e9ecda5ebfb2be5d0e2e4f36419ce56983c66606 Mon Sep 17 00:00:00 2001
From: Jens Nolte <git@queezle.net>
Date: Sun, 13 Mar 2022 03:20:39 +0100
Subject: [PATCH] Call async only once for liftA2 Observable
Co-authored-by: Jan Beinke <git@janbeinke.com>
---
src/Quasar/Observable.hs | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/src/Quasar/Observable.hs b/src/Quasar/Observable.hs
index 7c69ac1..c17c59b 100644
--- a/src/Quasar/Observable.hs
+++ b/src/Quasar/Observable.hs
@@ -237,9 +237,8 @@ data LiftA2Observable r = forall r0 r1. LiftA2Observable (r0 -> r1 -> r) (Observ
instance IsRetrievable r (LiftA2Observable r) where
retrieve (LiftA2Observable fn fx fy) = liftQuasarIO do
-- LATER: keep backpressure for parallel network requests
- x <- async $ retrieve fx
- y <- async $ retrieve fy
- liftA2 fn (await x) (await y)
+ future <- async $ retrieve fy
+ liftA2 fn (retrieve fx) (await future)
instance IsObservable r (LiftA2Observable r) where
observe (LiftA2Observable fn fx fy) callback = ensureQuasarSTM do
@@ -254,10 +253,9 @@ instance IsObservable r (LiftA2Observable r) where
pingObservable (LiftA2Observable _ fx fy) = liftQuasarIO do
-- LATER: keep backpressure for parallel network requests
- x <- async $ pingObservable fx
- y <- async $ pingObservable fy
- await x
- await y
+ future <- async $ pingObservable fy
+ pingObservable fx
+ await future
--data BindObservable r = forall a. BindObservable (Observable a) (a -> Observable r)
--
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