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Today's Topics:

   1.  Haskell REPL doesn't accept type declaration (Lawrence Bottorff)
   2. Re:  Haskell REPL doesn't accept type declaration
      (Francesco Ariis)
   3. Re:  Haskell REPL doesn't accept type declaration
      (Lawrence Bottorff)
   4. Re:  Haskell REPL doesn't accept type declaration
      (Francesco Ariis)
   5.  (no subject) (M Douglas McIlroy)


----------------------------------------------------------------------

Message: 1
Date: Thu, 10 Dec 2020 14:53:51 -0600
From: Lawrence Bottorff <borg...@gmail.com>
To: The Haskell-Beginners Mailing List - Discussion of primarily
        beginner-level topics related to Haskell <beginners@haskell.org>
Subject: [Haskell-beginners] Haskell REPL doesn't accept type
        declaration
Message-ID:
        <cafahfsw1vmm+xumplkbgsqq6e0td6eoev26e8csw7meld-u...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

If I simply put a type declaration into the GHCi (version 8.8.4), it
complains:

Prelude> divides :: Integer -> Integer -> Bool
<interactive>:18:1-7: error:
    Variable not in scope: divides :: Integer -> Integer -> Bool

I'm trying to use Emacs org-mode babel, and I have to wrap the code block
to get it to work. For example:

#+begin_src haskell :results verbatim :exports both
:{
factorial :: Int -> Int
factorial 0 = 1
factorial n = n * factorial (n - 1)
:}
#+end_src

#+begin_src haskell :results verbatim :exports both
factorial 0
#+end_src

#+RESULTS:
: 1

I understand :set +m, but this doesn't help. Why won't a running Haskell
REPL with set +m take a type declaration?

Lawrence Bottorff
Grand Marais, MN, USA
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Message: 2
Date: Thu, 10 Dec 2020 22:09:35 +0100
From: Francesco Ariis <fa...@ariis.it>
To: beginners@haskell.org
Subject: Re: [Haskell-beginners] Haskell REPL doesn't accept type
        declaration
Message-ID: <20201210210935.GC851@extensa>
Content-Type: text/plain; charset=utf-8

Il 10 dicembre 2020 alle 14:53 Lawrence Bottorff ha scritto:
> If I simply put a type declaration into the GHCi (version 8.8.4), it
> complains:
> 
> Prelude> divides :: Integer -> Integer -> Bool
> <interactive>:18:1-7: error:
>     Variable not in scope: divides :: Integer -> Integer -> Bool
> 
> I'm trying to use Emacs org-mode babel, and I have to wrap the code block
> to get it to work.

I do not believe it solves your problem but

    λ> prova :: Int; prova = 8
    λ>

works
—F


------------------------------

Message: 3
Date: Thu, 10 Dec 2020 15:41:06 -0600
From: Lawrence Bottorff <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] Haskell REPL doesn't accept type
        declaration
Message-ID:
        <cafahfswrdzqf41yfp5k2kqvhdckbidb5ayjp+xnx8vzeunw...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Yes, but a simple

λ> prova :: Int

doesn't work. What am I missing?


On Thu, Dec 10, 2020 at 3:11 PM Francesco Ariis <fa...@ariis.it> wrote:

> Il 10 dicembre 2020 alle 14:53 Lawrence Bottorff ha scritto:
> > If I simply put a type declaration into the GHCi (version 8.8.4), it
> > complains:
> >
> > Prelude> divides :: Integer -> Integer -> Bool
> > <interactive>:18:1-7: error:
> >     Variable not in scope: divides :: Integer -> Integer -> Bool
> >
> > I'm trying to use Emacs org-mode babel, and I have to wrap the code block
> > to get it to work.
>
> I do not believe it solves your problem but
>
>     λ> prova :: Int; prova = 8
>     λ>
>
> works
> —F
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
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Message: 4
Date: Thu, 10 Dec 2020 23:08:08 +0100
From: Francesco Ariis <fa...@ariis.it>
To: beginners@haskell.org
Subject: Re: [Haskell-beginners] Haskell REPL doesn't accept type
        declaration
Message-ID: <20201210220808.GA30311@extensa>
Content-Type: text/plain; charset=utf-8

Il 10 dicembre 2020 alle 15:41 Lawrence Bottorff ha scritto:
> Yes, but a simple
> 
> λ> prova :: Int
> 
> doesn't work. What am I missing?

No idea the reason why ghci does not accept it, maybe because if it did
there would be a bodyless signature in scope?

Also maybe this is slightly more palatable for you:

    λ> :set +m
    λ> let prova :: Int -> String
           prova = show
    [blank line]
    λ> prova 7
    "7"




------------------------------

Message: 5
Date: Thu, 10 Dec 2020 22:57:26 -0500
From: M Douglas McIlroy <m.douglas.mcil...@dartmouth.edu>
To: beginners@haskell.org
Subject: [Haskell-beginners] (no subject)
Message-ID:
        <cakh6piw_obirvt55mspcn_ye+hm2me5bam-k0inman+kqkl...@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

Is it possible to decorate a definition like this


------------------------------

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