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You can reach the person managing the list at beginners-ow...@haskell.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Beginners digest..." Today's Topics: 1. How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt (Galaxy Being) 2. Re: How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt (Francesco Ariis) 3. Re: How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt (Galaxy Being) 4. Closure: exact wording (Galaxy Being) ---------------------------------------------------------------------- Message: 1 Date: Fri, 26 Mar 2021 12:20:55 -0500 From: Galaxy Being <borg...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <beginners@haskell.org> Subject: [Haskell-beginners] How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt Message-ID: <CAFAhFSXg=q4EVK1u+bE0WpkT==dzao2gfy7q-k8mfmhr6hz...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" I've got this code I've entered into the ghci by hand between :{ and :} :{ {-# LANGUAGE LambdaCase #-} data List a = Empty | Cons a (List a) deriving (Eq, Ord, Show) infixr 5 `Cons` subst_c :: (a -> Bool) -> (a, MyList a) -> MyList a subst_c pred = \ case (_, Empty) -> Empty (n, Cons e t) | pred e -> Cons n $ subst_c pred (n, t) | otherwise -> Cons e $ subst_c pred (n, t) :} but I keep getting the error Illegal lambda-case (use -XLambdaCase) This works fine inside an .hs file and :load and run at the prompt. However, I'm using Emacs org-mode and need to keep everything limited to a version of hand-entered :{ ... :}. Any suggestions? LB -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/beginners/attachments/20210326/1fc0b93c/attachment-0001.html> ------------------------------ Message: 2 Date: Fri, 26 Mar 2021 18:31:53 +0100 From: Francesco Ariis <fa...@ariis.it> To: beginners@haskell.org Subject: Re: [Haskell-beginners] How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt Message-ID: <20210326173152.GA9876@extensa> Content-Type: text/plain; charset=utf-8 Il 26 marzo 2021 alle 12:20 Galaxy Being ha scritto: > I've got this code I've entered into the ghci by hand between :{ and :} > > :{ > {-# LANGUAGE LambdaCase #-} > data List a = Empty | Cons a (List a) deriving (Eq, Ord, Show) > infixr 5 `Cons` > > subst_c :: (a -> Bool) -> (a, MyList a) -> MyList a > subst_c pred = \ case > (_, Empty) -> Empty > (n, Cons e t) > | pred e -> Cons n $ subst_c pred (n, t) > | otherwise -> Cons e $ subst_c pred (n, t) > :} > λ> :set -XLambdaCase ------------------------------ Message: 3 Date: Fri, 26 Mar 2021 16:17:19 -0500 From: Galaxy Being <borg...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <beginners@haskell.org> Subject: Re: [Haskell-beginners] How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt Message-ID: <cafahfsupblaloic-xxcvbdfo_czc5cazq1pqyodkp5pgchu...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" Exactly. Thanks. On Fri, Mar 26, 2021 at 12:33 PM Francesco Ariis <fa...@ariis.it> wrote: > Il 26 marzo 2021 alle 12:20 Galaxy Being ha scritto: > > I've got this code I've entered into the ghci by hand between :{ and :} > > > > :{ > > {-# LANGUAGE LambdaCase #-} > > data List a = Empty | Cons a (List a) deriving (Eq, Ord, Show) > > infixr 5 `Cons` > > > > subst_c :: (a -> Bool) -> (a, MyList a) -> MyList a > > subst_c pred = \ case > > (_, Empty) -> Empty > > (n, Cons e t) > > | pred e -> Cons n $ subst_c pred (n, t) > > | otherwise -> Cons e $ subst_c pred (n, t) > > :} > > > > λ> :set -XLambdaCase > _______________________________________________ > Beginners mailing list > Beginners@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/beginners/attachments/20210326/4003fd03/attachment-0001.html> ------------------------------ Message: 4 Date: Fri, 26 Mar 2021 16:32:01 -0500 From: Galaxy Being <borg...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <beginners@haskell.org> Subject: [Haskell-beginners] Closure: exact wording Message-ID: <CAFAhFSWXUBhncwiOQrGZF5=eaz5rfns_hyc1mdyyegrptap...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" I've got this addTwo x y = x + y aT5 = addTwo 5 > aT5 3 8 Is it right to say aT5 is a closure over 5, or a closure over addTwo 5? LB -------------- next part -------------- An HTML attachment was scrubbed... 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