2025/12/03

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2025-12-03 16:12:22 +0100califax_(~califax@user/califx) califx
2025-12-03 16:11:00 +0100 <lambdabot> [2,4,6,8,5,6,7,8,9,10]
2025-12-03 16:11:00 +0100 <__monty__> But the idea works.
2025-12-03 16:10:56 +0100 <kuribas`> > foldr (\(x:xs) cont s -> if (s > 7) then (x:xs) else (x*2) : cont (s+x)) (const []) (tails [1..10]) 0
2025-12-03 16:10:56 +0100spew(~spew@user/spew) spew
2025-12-03 16:10:44 +0100 <__monty__> This is the missing case analysis I was referring to.
2025-12-03 16:10:39 +0100spew(~spew@user/spew) (Quit: nyaa~)
2025-12-03 16:10:30 +0100 <lambdabot> [2,4,6,8,10,12,14,16,18,20*Exception: <interactive>:3:8-59: Non-exhaustive p...
2025-12-03 16:10:27 +0100 <__monty__> > foldr (\(x:xs) xs2 -> if False then (x:xs) else (x*2) : xs2) [] (tails [1..10])
2025-12-03 16:10:08 +0100gawen(~gawen@user/gawen) gawen
2025-12-03 16:09:40 +0100wbooze(~inline@cgn-195-14-221-120.nc.de) (Quit: Leaving)
2025-12-03 16:09:08 +0100 <kuribas`> You can use the continuation if you need to pass some state.
2025-12-03 16:08:44 +0100 <lambdabot> [2,4,6,8,10,6,7,8,9,10]
2025-12-03 16:08:41 +0100 <kuribas`> > foldr (\(x:xs) xs2 -> if (x > 5) then (x:xs) else (x*2) : xs2) [] (tails [1..10])
2025-12-03 16:08:38 +0100 <kuribas`> Actually, this doesn't use the continuation ...
2025-12-03 16:07:41 +0100 <__monty__> Hmm, no the span/break would need to carry state forward.
2025-12-03 16:07:06 +0100 <__monty__> Feels a lot like span/break and folding the fst.
2025-12-03 16:05:52 +0100 <__monty__> Only shortcoming is if the condition is never fulfilled, needs more case analysis.
2025-12-03 16:05:29 +0100lucabtz(~lucabtz@user/lucabtz) lucabtz
2025-12-03 16:04:45 +0100amadaluzia(~amadaluzi@user/amadaluzia) amadaluzia
2025-12-03 16:04:39 +0100 <kuribas`> --proof that it doesn't visit the tail :)
2025-12-03 16:04:26 +0100 <lambdabot> [2,4,6,8,10,6,7,8,9,10]
2025-12-03 16:04:23 +0100 <kuribas`> > take 10 $ foldr (\(x:xs) cont -> \xs2 -> if (x > 5) then (x:xs) else (x*2) : cont xs) id (tails [1..]) []
2025-12-03 16:03:03 +0100spew(~spew@user/spew) spew
2025-12-03 16:02:40 +0100lucabtz(~lucabtz@user/lucabtz) (Remote host closed the connection)
2025-12-03 16:01:59 +0100ttybitnik(~ttybitnik@user/wolper) (Quit: Fading out...)
2025-12-03 16:01:28 +0100divlamir(~divlamir@user/divlamir) (Ping timeout: 244 seconds)
2025-12-03 16:00:45 +0100spew(~spew@user/spew) (Ping timeout: 245 seconds)
2025-12-03 16:00:00 +0100 <kuribas`> obviously needs some lambdacase.
2025-12-03 15:59:41 +0100 <kuribas`> ^ __monty__
2025-12-03 15:59:36 +0100 <lambdabot> [2,4,6,8,10,6,7,8,9,10]
2025-12-03 15:59:30 +0100 <kuribas`> > foldr (\(x:xs) cont -> \xs2 -> if (x > 5) then (x:xs) else (x*2) : cont xs) id (tails [1..10]) []
2025-12-03 15:51:23 +0100wbooze(~inline@cgn-195-14-221-120.nc.de) Inline
2025-12-03 15:47:39 +0100Guest6657(~inline@cgn-195-14-221-120.nc.de) (Quit: Leaving)
2025-12-03 15:45:27 +0100gawen(~gawen@user/gawen) (Quit: cya)
2025-12-03 15:40:33 +0100 <sprout> yah
2025-12-03 15:40:24 +0100 <tomsmeding> then you just punt the problem to the implementation of that monad
2025-12-03 15:39:45 +0100 <sprout> put it in a monad? I feel like parser combinators will often return the unprocessed tokens on an error, so you should be able to reuse the idiom
2025-12-03 15:37:58 +0100Pozyomka(~pyon@user/pyon) pyon
2025-12-03 15:37:57 +0100 <sprout> hmyah
2025-12-03 15:37:55 +0100akegalj(~akegalj@141-138-27-206.dsl.iskon.hr)
2025-12-03 15:37:53 +0100 <__monty__> sprout: Again, that leaves me with only part of the input, no?
2025-12-03 15:37:48 +0100 <tomsmeding> sprout: scan doesn't give you access to the actual original tail
2025-12-03 15:37:26 +0100 <__monty__> But that's not the "shortcutting" I'm looking for. I want to recurse up to a point and at that point return the tail unprocessed. The latter is just for efficiency rather than correctness.
2025-12-03 15:37:20 +0100 <sprout> you can do a scan instead of a fold and lazily stop evaluating when you hit something
2025-12-03 15:36:23 +0100 <tomsmeding> yes I think so
2025-12-03 15:35:58 +0100 <__monty__> Yeah, with foldr you can either process every element, or drop whatever's left.
2025-12-03 15:35:01 +0100 <__monty__> kuribas`: Show me a foldr that doesn't drop any values and also doesn't visit a tail of several values.
2025-12-03 15:34:46 +0100 <tomsmeding> but while that construction is cute, I don't think you get access to the unadulterated tail
2025-12-03 15:34:29 +0100 <tomsmeding> base's foldl is implemented using foldr