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Today's Topics:
1. point-free + IO Monad (Ovidiu D)
2. Re: point-free + IO Monad (Franco)
3. Re: point-free + IO Monad (Ovidiu D)
4. Re: point-free + IO Monad (Tony Morris)
----------------------------------------------------------------------
Message: 1
Date: Sun, 31 Mar 2013 09:55:24 +0300
From: Ovidiu D <[email protected]>
Subject: [Haskell-beginners] point-free + IO Monad
To: [email protected]
Message-ID:
<cakvse7t0+tv_f1dkpnbto1w3i_v83-r5yi-icrgp6+j2jpo...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I have the following code:
f1 :: String -> String
f2 :: IO String -> IO ()
f2 a = do
b <- a
putStr $ f1 b
How can I write the function f2 in a point-free style?
I have tried this:
f2 = return.f1 >>= putStr
...but it doesn't work.
Thanks!
------------------------------
Message: 2
Date: Sun, 31 Mar 2013 08:08:30 +0000 (UTC)
From: Franco <[email protected]>
Subject: Re: [Haskell-beginners] point-free + IO Monad
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Ovidiu D <ovidiudeac <at> gmail.com> writes:
>
> I have the following code:
>
> f1 :: String -> String
>
> f2 :: IO String -> IO ()
> f2 a = do
> b <- a
> putStr $ f1 b
>
> How can I write the function f2 in a point-free style?
>
maybe
f2 = (=<<) (putStrLn . f1)
I still prefer the non point-free but clearer
f2 = a >>= (putStrLn . f1)
------------------------------
Message: 3
Date: Sun, 31 Mar 2013 12:27:49 +0300
From: Ovidiu D <[email protected]>
Subject: Re: [Haskell-beginners] point-free + IO Monad
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Message-ID:
<cakvse7v1f9asc0ev+5uabocq_kwev9kccyxgnersouvajz+...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
That's good enough. Thanks!
On Sun, Mar 31, 2013 at 11:08 AM, Franco <[email protected]> wrote:
> Ovidiu D <ovidiudeac <at> gmail.com> writes:
>
> >
> > I have the following code:
> >
> > f1 :: String -> String
> >
> > f2 :: IO String -> IO ()
> > f2 a = do
> > b <- a
> > putStr $ f1 b
> >
> > How can I write the function f2 in a point-free style?
> >
>
> maybe
>
> f2 = (=<<) (putStrLn . f1)
>
> I still prefer the non point-free but clearer
>
> f2 = a >>= (putStrLn . f1)
>
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
>
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Message: 4
Date: Sun, 31 Mar 2013 19:59:25 +1000
From: Tony Morris <[email protected]>
Subject: Re: [Haskell-beginners] point-free + IO Monad
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Message-ID:
<cajf6usiwlxh1c-mej-z+g+9qk5acxlpf8twudxow20j5y_o...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
You can drop the parens if you like.
f2 a = putStrLn . f1 =<< a -- my preference
f2 a = a >>= putStrLn . f1
On 31/03/2013 7:29 PM, "Ovidiu D" <[email protected]> wrote:
> That's good enough. Thanks!
>
>
> On Sun, Mar 31, 2013 at 11:08 AM, Franco <[email protected]> wrote:
>
>> Ovidiu D <ovidiudeac <at> gmail.com> writes:
>>
>> >
>> > I have the following code:
>> >
>> > f1 :: String -> String
>> >
>> > f2 :: IO String -> IO ()
>> > f2 a = do
>> > b <- a
>> > putStr $ f1 b
>> >
>> > How can I write the function f2 in a point-free style?
>> >
>>
>> maybe
>>
>> f2 = (=<<) (putStrLn . f1)
>>
>> I still prefer the non point-free but clearer
>>
>> f2 = a >>= (putStrLn . f1)
>>
>>
>>
>> _______________________________________________
>> Beginners mailing list
>> [email protected]
>> http://www.haskell.org/mailman/listinfo/beginners
>>
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
>
>
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