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| 2025-03-21 16:50:26 +0100 | wildsalander | (~wildsalan@81-175-155-97.bb.dnainternet.fi) (Ping timeout: 252 seconds) |
| 2025-03-21 16:50:04 +0100 | euleritian | (~euleritia@ip5f5ad695.dynamic.kabel-deutschland.de) (Ping timeout: 252 seconds) |
| 2025-03-21 16:45:40 +0100 | wildsalander | (~wildsalan@81-175-155-97.bb.dnainternet.fi) |
| 2025-03-21 16:43:39 +0100 | euleritian | (~euleritia@ip5f5ad695.dynamic.kabel-deutschland.de) |
| 2025-03-21 16:43:13 +0100 | euleritian | (~euleritia@dynamic-176-006-136-021.176.6.pool.telefonica.de) (Read error: Connection reset by peer) |
| 2025-03-21 16:42:54 +0100 | <EvanR> | ok I got confused, = is the relation being defined |
| 2025-03-21 16:41:51 +0100 | jespada | (~jespada@2800:a4:228e:4800:8c77:166d:4542:2a56) (Quit: My Mac has gone to sleep. ZZZzzz…) |
| 2025-03-21 16:41:13 +0100 | L29Ah | (~L29Ah@wikipedia/L29Ah) () |
| 2025-03-21 16:40:22 +0100 | wildsalander | (~wildsalan@81-175-155-97.bb.dnainternet.fi) (Ping timeout: 268 seconds) |
| 2025-03-21 16:38:41 +0100 | <EvanR> | (and other properties but, they also involve "=") |
| 2025-03-21 16:38:11 +0100 | <EvanR> | xD |
| 2025-03-21 16:37:28 +0100 | <EvanR> | was just reading about "presets" which are setoids (a set that comes equipped with an equivalence relation) without the equivalence relation provided. And then it explained "a preset becomes a set if you give it a relation which.... is reflexive (x = x)" |
| 2025-03-21 16:37:14 +0100 | <tomsmeding> | also not particularly efficient. |
| 2025-03-21 16:36:10 +0100 | <absence> | Proving things with singletons sounds like it will quickly escalate into "not worth it". :p |
| 2025-03-21 16:34:24 +0100 | <tomsmeding> | we're in #haskell, not in #agda ;) |
| 2025-03-21 16:34:04 +0100 | <EvanR> | type O |
| 2025-03-21 16:34:00 +0100 | <EvanR> | er |
| 2025-03-21 16:33:58 +0100 | <EvanR> | oh was reading : as "type off" |
| 2025-03-21 16:33:57 +0100 | <tomsmeding> | seems so |
| 2025-03-21 16:33:55 +0100 | <lambdabot> | True |
| 2025-03-21 16:33:54 +0100 | <tomsmeding> | > x == x |
| 2025-03-21 16:33:35 +0100 | <EvanR> | x = x ? |
| 2025-03-21 16:33:18 +0100 | <tomsmeding> | Now, even the implication `Subset a b => Subset (x:a) (x:b)` is not directly inferrable from the given instances, but you could prove it perhaps, given singletons for those lists |
| 2025-03-21 16:32:49 +0100 | <absence> | Oh right, that makes sense. |
| 2025-03-21 16:32:01 +0100 | <tomsmeding> | [1,1] is a subset of [1,2], but [1] is not a subset of [2] |
| 2025-03-21 16:31:36 +0100 | <tomsmeding> | absence: sure, Subset a b implies Subset (x:a) (x:b). But the other way round does not hold |
| 2025-03-21 16:31:12 +0100 | <absence> | I'm not sure I see how adding an x to both of them breaks the subset relationship... |
| 2025-03-21 16:30:27 +0100 | as___ | (~as@2800:a4:396:c900:c2ca:9624:369a:7d24) (Ping timeout: 265 seconds) |
| 2025-03-21 16:28:31 +0100 | berzerk | (~berzerk@2800:a4:396:c900:c2ca:9624:369a:7d24) (Ping timeout: 265 seconds) |
| 2025-03-21 16:26:47 +0100 | aristid | (sid1599@id-1599.uxbridge.irccloud.com) |
| 2025-03-21 16:25:56 +0100 | jackdk | (sid373013@cssa/jackdk) jackdk |
| 2025-03-21 16:25:08 +0100 | alfiee | (~alfiee@user/alfiee) (Ping timeout: 252 seconds) |
| 2025-03-21 16:24:44 +0100 | <tomsmeding> | that |
| 2025-03-21 16:24:37 +0100 | <tomsmeding> | absence: Note that `Subset (x : list1) (x : list2)` is NOT equivalent to `Subset list1 list2`: the former allows elements of list1 to be equal to x, whereas the latter only allows that if x is in list2 |
| 2025-03-21 16:24:29 +0100 | <int-e> | Looks like Subset (x : list1) (x : list2) should simplify to Subset list1 (x : list2), but there's nothing that ensures that list1 doesn't contain another x... |
| 2025-03-21 16:23:43 +0100 | aristid | (sid1599@id-1599.uxbridge.irccloud.com) (Ping timeout: 268 seconds) |
| 2025-03-21 16:23:42 +0100 | jackdk | (sid373013@cssa/jackdk) (Ping timeout: 244 seconds) |
| 2025-03-21 16:23:29 +0100 | <absence> | Speaking of vibes, it feels vaguely similar to "(Monad (t m), Monad m, MonadTrans t) =>", so maybe something something QuantifiedConstraints...? |
| 2025-03-21 16:22:57 +0100 | taktoa[c] | (sid282096@id-282096.tinside.irccloud.com) taktoa[c] |
| 2025-03-21 16:22:45 +0100 | <tomsmeding> | ah, so `Subset list1 list2 => Subset (x : list1) (x : list2)` itself isn't even directly derivable |
| 2025-03-21 16:21:38 +0100 | taktoa[c] | (sid282096@id-282096.tinside.irccloud.com) (Ping timeout: 244 seconds) |
| 2025-03-21 16:21:17 +0100 | <absence> | Here's the constraint by the way: https://hackage.haskell.org/package/effectful-core-2.5.1.0/docs/src/Effectful.Internal.Effect.html… |
| 2025-03-21 16:20:54 +0100 | alfiee | (~alfiee@user/alfiee) alfiee |
| 2025-03-21 16:20:50 +0100 | <tomsmeding> | I'm not 100% sure this is what you are running into, but it has a similar "vibe" :p |
| 2025-03-21 16:20:33 +0100 | <tomsmeding> | you have to modify the class |
| 2025-03-21 16:20:29 +0100 | <tomsmeding> | no |
| 2025-03-21 16:20:11 +0100 | <absence> | Can I do that if the constraint and the function that needs it are defined in a third-party library? |
| 2025-03-21 16:19:58 +0100 | <tomsmeding> | if you don't know what I'm talking about, or don't know how it applies to your case, you'll have to share the definition of that Subset thing |
| 2025-03-21 16:19:35 +0100 | <tomsmeding> | the latter is normally _not_ what GHC does |
| 2025-03-21 16:19:26 +0100 | <tomsmeding> | that allows ghc to, given an `instance C A => C T` not only infer `C T` from `C A`, but furthermore conclude from evidence of `C T` that `C A` must also hold |