2024/04/28

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2024-04-28 12:19:12 +0200wootehfoot(~wootehfoo@user/wootehfoot)
2024-04-28 12:18:35 +0200mima(~mmh@eduroam-pool4-264.wlan.uni-bremen.de) (Ping timeout: 260 seconds)
2024-04-28 12:18:14 +0200wootehfoot(~wootehfoo@user/wootehfoot) (Read error: Connection reset by peer)
2024-04-28 12:18:02 +0200 <ski> iow, i'd prefer to be given the choice of using the usual type signatures, or a more C-style mixed definiendum & type ascriptions. (or both, or neither)
2024-04-28 12:16:55 +0200 <ski> (otoh, the MLs doesn't have separate type signatures, interleaved with implementation. you can only put those in signatures (/ module types))
2024-04-28 12:16:02 +0200 <yin> i see
2024-04-28 12:15:46 +0200 <ski> unlike in the MLs, where this works just fine
2024-04-28 12:15:35 +0200 <ski> yea, but that only works for pattern bindings, yin
2024-04-28 12:15:23 +0200 <ski> yea, but i'd rather have the option to express a full signature in this style, in addition to the usual separate type signature. rather than *almost*, but not quite, being able to do this
2024-04-28 12:15:21 +0200 <yin> e
2024-04-28 12:15:16 +0200 <yin> foo :: Bool = True -- works just fin
2024-04-28 12:14:41 +0200 <yin> we can't do that anymore?
2024-04-28 12:14:26 +0200 <tomsmeding> at that point just write a type signature :p
2024-04-28 12:14:23 +0200 <ski> the ` :: [b]' there, specifically
2024-04-28 12:14:13 +0200 <ski> map (f :: a -> b) (xs0 :: [a]) :: [b] = case xs0 of ...
2024-04-28 12:13:56 +0200 <yin> ski: wdym?
2024-04-28 12:13:46 +0200 <ski> .. i miss the ability to put a type ascription on the whole definiendum
2024-04-28 12:13:21 +0200 <yin> forget the |
2024-04-28 12:13:15 +0200 <yin> *i mean
2024-04-28 12:13:15 +0200 <tomsmeding> it's never strictly necessary, but can be very convenient in some cases
2024-04-28 12:13:13 +0200 <ski> the definiendum of the defining equation
2024-04-28 12:13:13 +0200 <yin> i man
2024-04-28 12:13:12 +0200wootehfoot(~wootehfoo@user/wootehfoot)
2024-04-28 12:13:02 +0200 <yin> or |
2024-04-28 12:12:59 +0200 <yin> tomsmeding: left of the = on a function definition
2024-04-28 12:12:54 +0200 <tomsmeding> a type annotation in a pattern?
2024-04-28 12:12:47 +0200 <tomsmeding> what does "function head" mean?
2024-04-28 12:12:47 +0200 <yin> or is it just a convenience
2024-04-28 12:12:32 +0200 <yin> i guess my question is: do we really need the ability to annotate on the function head?
2024-04-28 12:09:28 +0200wootehfoot(~wootehfoo@user/wootehfoot) (Read error: Connection reset by peer)
2024-04-28 12:08:51 +0200 <tomsmeding> it's a workaround to be sure
2024-04-28 12:08:47 +0200 <tomsmeding> that helper function could have a type signature from which you can get your type variables with ScopedTypeVariables
2024-04-28 12:08:34 +0200mima(~mmh@eduroam-pool4-264.wlan.uni-bremen.de)
2024-04-28 12:08:25 +0200 <tomsmeding> you could also write a helper function that you pass your matched things to
2024-04-28 12:07:19 +0200 <ski> "I think it's never actually necessary" -- introducing a type variable for an opened existential
2024-04-28 12:05:36 +0200mima(~mmh@eduroam-pool4-264.wlan.uni-bremen.de) (Ping timeout: 268 seconds)
2024-04-28 12:04:09 +0200 <tomsmeding> yin: indeed, it's a type annotation that you can put in a convenient spot
2024-04-28 12:03:52 +0200 <int-e> (wrong channel)
2024-04-28 12:03:45 +0200 <lambdabot> -9223372036854775808
2024-04-28 12:03:43 +0200 <yin> > minBound :: Int
2024-04-28 12:03:38 +0200 <yin> somehow i don't consider that to be patter matching. it's just like
2024-04-28 12:03:26 +0200wootehfoot(~wootehfoo@user/wootehfoot)
2024-04-28 12:03:10 +0200 <int-e> tomsmeding: oh the cloudatacost.com fan page is gone, so sad. https://web.archive.org/web/20220811231349/https://cloudatacost.com/mystory/original-story-2014
2024-04-28 12:02:51 +0200 <yin> oh i see
2024-04-28 12:02:25 +0200 <tomsmeding> it's nicer to write `catch _ (\(e :: IOException) -> ...)`
2024-04-28 12:02:14 +0200 <tomsmeding> you typically have to manually constrain e somehow, and having to do that on some occurrence in the body is kind of clunky
2024-04-28 12:02:08 +0200 <yin> yes
2024-04-28 12:01:54 +0200 <tomsmeding> yin: do you see the `(e :: IOException)` in the example in the haddocks?
2024-04-28 12:01:34 +0200 <tomsmeding> so then ghc asks you to say precisely what you mean -- some specific instantiation, or an actual polymorphic type where it's then on you to write down what ghc should do
2024-04-28 12:01:14 +0200 <yin> tomsmeding: where's the type annotation on pattern matching in 'catch'?