Re: Beginners Digest, Vol 89, Issue 38 How to define a simple function

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Re: Beginners Digest, Vol 89, Issue 38 How to define a simple function

Francisco Gutierrez
Dear sirs:
I am defining a function halve, that breaks a list in two halfs. But I always get an error. Below is my code. What am I doing wrong?
Thanks!
halve xs = [take (floor (longitud/2)), drop (floor (longitud/2))] 
where longitud = length xs




From: "[hidden email]" <[hidden email]>
To: [hidden email]
Sent: Saturday, November 21, 2015 8:21 PM
Subject: Beginners Digest, Vol 89, Issue 38

Send Beginners mailing list submissions to
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To subscribe or unsubscribe via the World Wide Web, visit
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of Beginners digest..."


Today's Topics:

  1. Re:  Warning: Tab Character (Dan Stromberg)
  2. Re:  Warning: Tab Character (Jeon-Young Kang)
  3. Re:  Warning: Tab Character (Thomas Jakway)


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

Message: 1
Date: Sat, 21 Nov 2015 16:44:21 -0800
From: Dan Stromberg <[hidden email]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
    beginner-level topics related to Haskell <[hidden email]>
Subject: Re: [Haskell-beginners] Warning: Tab Character
Message-ID:
    <CAOvKW55oxCcEhtqppC0bXQZjOEEv5vcYnBTWHaj9C5vhhm7g+[hidden email]>
Content-Type: text/plain; charset="utf-8"

I believe the first version of make required tabs, but some subsequent
versions have relaxed that requirement to make things easier.

Here's an example on a Linux Mint system (the 20's are of course spaces) :
$ od -cx < Makefile
cmd output started 2015 Sat Nov 21 04:39:47 PM PST
0000000  \n  g  o  :  \n                  .  /  t  \n  \n
          670a    3a6f    200a    2020    2e20    742f    0a0a
0000016
above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
[hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234

$ make
cmd output started 2015 Sat Nov 21 04:39:48 PM PST
Makefile:3: *** missing separator.  Stop.
above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
[hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234

$ make --version
cmd output started 2015 Sat Nov 21 04:39:53 PM PST
GNU Make 3.81
Copyright (C) 2006  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

This program built for i686-pc-linux-gnu
above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
[hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234


I'll add that vim's Makefile syntax highlighting puts the space-indented
line in red, suggesting an error.  Changing the spaces to a single tab
makes the red go away.

HTH

On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:

> Why would make require tabs...?
> Admittedly it's been a long time since I've written any makefiles by hand
> but I always use spaces instead of tabs and have never had any problems.
>
> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
> >
> > Have you found "soft tabs"? That option will make TextMate use spaces
> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs" in Dan
> Strombergs link for instrucitons.
> >
> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
> >>
> >> I've tried to choose "instead of spaces". But there is no option of
> mine (Textmate 2 beta).
> >>
> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]>
> wrote:
> >>>
> >>>
> >>> Perhaps enable soft tabs?
> >>> https://manual.macromates.com/en/working_with_text
> >>>
> >>> This is an issue in Python too (at least from PEP8's perspective) -
> but note that many "make" programs require tabs instead of spaces.
> >>>
> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang <[hidden email]>
> wrote:
> >>>>
> >>>> Hello everyone.
> >>>>
> >>>>
> >>>> I am a newbie of Haskell, using Textmate on mac.
> >>>>
> >>>>
> >>>> I got the following warning. How can I fix it?
> >>>>
> >>>>
> >>>> Warning:
> >>>>
> >>>>    Tab character
> >>>>
> >>>> Ok, modules loaded: Main.
> >>>>
> >>>>
> >>>>
> >>>> Sincerely,
> >>>> Young
> >>>>
> >>>> _______________________________________________
> >>>> Beginners mailing list
> >>>> [hidden email]
> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> Dan Stromberg
> >>>
> >>> _______________________________________________
> >>> Beginners mailing list
> >>> [hidden email]
> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> >>>
> >>
> >>
> >>
> >> --
> >> Department of Geography
> >> State University of New York at Buffalo
> >>
> >> [hidden email]
> >>
> >> Jeon-Young Kang
> >>
> >> _______________________________________________
> >> Beginners mailing list
> >> [hidden email]
> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> >>
> >
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>



--
Dan Stromberg
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------------------------------

Message: 2
Date: Sat, 21 Nov 2015 20:03:08 -0500
From: Jeon-Young Kang <[hidden email]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
    beginner-level topics related to Haskell <[hidden email]>
Subject: Re: [Haskell-beginners] Warning: Tab Character
Message-ID:
    <CALWtiK8DqDr292Bb=J7rEa8unXBrRTt6++[hidden email]>
Content-Type: text/plain; charset="utf-8"

Thanks! I figured out.

On Sat, Nov 21, 2015 at 7:44 PM, Dan Stromberg <[hidden email]> wrote:

>
> I believe the first version of make required tabs, but some subsequent
> versions have relaxed that requirement to make things easier.
>
> Here's an example on a Linux Mint system (the 20's are of course spaces) :
> $ od -cx < Makefile
> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
> 0000000  \n  g  o  :  \n                  .  /  t  \n  \n
>            670a    3a6f    200a    2020    2e20    742f    0a0a
> 0000016
> above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make
> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
> Makefile:3: *** missing separator.  Stop.
> above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make --version
> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
> GNU Make 3.81
> Copyright (C) 2006  Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.
> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
> PARTICULAR PURPOSE.
>
> This program built for i686-pc-linux-gnu
> above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
>
> I'll add that vim's Makefile syntax highlighting puts the space-indented
> line in red, suggesting an error.  Changing the spaces to a single tab
> makes the red go away.
>
> HTH
>
> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:
>
>> Why would make require tabs...?
>> Admittedly it's been a long time since I've written any makefiles by hand
>> but I always use spaces instead of tabs and have never had any problems.
>>
>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>> >
>> > Have you found "soft tabs"? That option will make TextMate use spaces
>> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs" in Dan
>> Strombergs link for instrucitons.
>> >
>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>> >>
>> >> I've tried to choose "instead of spaces". But there is no option of
>> mine (Textmate 2 beta).
>> >>
>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]>
>> wrote:
>> >>>
>> >>>
>> >>> Perhaps enable soft tabs?
>> >>> https://manual.macromates.com/en/working_with_text
>> >>>
>> >>> This is an issue in Python too (at least from PEP8's perspective) -
>> but note that many "make" programs require tabs instead of spaces.
>> >>>
>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang <[hidden email]>
>> wrote:
>> >>>>
>> >>>> Hello everyone.
>> >>>>
>> >>>>
>> >>>> I am a newbie of Haskell, using Textmate on mac.
>> >>>>
>> >>>>
>> >>>> I got the following warning. How can I fix it?
>> >>>>
>> >>>>
>> >>>> Warning:
>> >>>>
>> >>>>    Tab character
>> >>>>
>> >>>> Ok, modules loaded: Main.
>> >>>>
>> >>>>
>> >>>>
>> >>>> Sincerely,
>> >>>> Young
>> >>>>
>> >>>> _______________________________________________
>> >>>> Beginners mailing list
>> >>>> [hidden email]
>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> Dan Stromberg
>> >>>
>> >>> _______________________________________________
>> >>> Beginners mailing list
>> >>> [hidden email]
>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> Department of Geography
>> >> State University of New York at Buffalo
>> >>
>> >> [hidden email]
>> >>
>> >> Jeon-Young Kang
>> >>
>> >> _______________________________________________
>> >> Beginners mailing list
>> >> [hidden email]
>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>
>> >
>> _______________________________________________
>> Beginners mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>
>
>
>
> --
> Dan Stromberg
>
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
>


--
Department of Geography
State University of New York at Buffalo

[hidden email]

Jeon-Young Kang
-------------- next part --------------
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------------------------------

Message: 3
Date: Sat, 21 Nov 2015 20:22:04 -0500
From: Thomas Jakway <[hidden email]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
    beginner-level topics related to Haskell <[hidden email]>
Subject: Re: [Haskell-beginners] Warning: Tab Character
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=utf-8

Huh, cool.  I had no idea.  Thanks!

On Nov 21, 2015 7:44 PM, Dan Stromberg <[hidden email]> wrote:

>
>
> I believe the first version of make required tabs, but some subsequent versions have relaxed that requirement to make things easier.
>
> Here's an example on a Linux Mint system (the 20's are of course spaces) :
> $ od -cx < Makefile
> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
> 0000000? \n?? g?? o?? :? \n?????????????????? .?? /?? t? \n? \n
> ?????????? 670a??? 3a6f??? 200a??? 2020??? 2e20??? 742f??? 0a0a
> 0000016
> above cmd output done??? 2015 Sat Nov 21 04:39:47 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make
> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
> Makefile:3: *** missing separator.? Stop.
> above cmd output done??? 2015 Sat Nov 21 04:39:48 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make --version
> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
> GNU Make 3.81
> Copyright (C) 2006? Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.
> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
> PARTICULAR PURPOSE.
>
> This program built for i686-pc-linux-gnu
> above cmd output done??? 2015 Sat Nov 21 04:39:53 PM PST
> [hidden email]:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
>
> I'll add that vim's Makefile syntax highlighting puts the space-indented line in red, suggesting an error.? Changing the spaces to a single tab makes the red go away.
>
> HTH
>
> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:
>>
>> Why would make require tabs...?
>> Admittedly it's been a long time since I've written any makefiles by hand but I always use spaces instead of tabs and have never had any problems.
>>
>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>> >
>> > Have you found "soft tabs"? That option will make?TextMate use spaces instead of tab characters. Read?4.11 "Using Spaces Instead of Tabs" in Dan Strombergs link for instrucitons.
>> >
>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>> >>
>> >> I've tried to choose "instead of spaces". But there is no option of mine (Textmate 2 beta).
>> >>
>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]> wrote:
>> >>>
>> >>>
>> >>> Perhaps enable soft tabs?
>> >>> https://manual.macromates.com/en/working_with_text
>> >>>
>> >>> This is an issue in Python too (at least from PEP8's perspective) - but note that many "make" programs require tabs instead of spaces.
>> >>>
>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang <[hidden email]> wrote:
>> >>>>
>> >>>> Hello everyone.
>> >>>>
>> >>>>
>> >>>> I am a newbie of Haskell, using Textmate on mac.
>> >>>>
>> >>>>
>> >>>> I got the following warning. How can I fix it?
>> >>>>
>> >>>>
>> >>>> Warning:
>> >>>>
>> >>>> ? ? Tab character
>> >>>>
>> >>>> Ok, modules loaded: Main.
>> >>>>
>> >>>>
>> >>>>
>> >>>> Sincerely,
>> >>>> Young
>> >>>>
>> >>>> _______________________________________________
>> >>>> Beginners mailing list
>> >>>> [hidden email]
>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> Dan Stromberg
>> >>>
>> >>> _______________________________________________
>> >>> Beginners mailing list
>> >>> [hidden email]
>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> Department of Geography
>> >> State University of New York at Buffalo
>> >>
>> >> [hidden email]
>> >> ?
>> >> Jeon-Young Kang
>> >>
>> >> _______________________________________________
>> >> Beginners mailing list
>> >> [hidden email]
>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>
>> >
>> _______________________________________________
>> Beginners mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
>
>
>
> --
> Dan Stromberg

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

Subject: Digest Footer

_______________________________________________
Beginners mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners


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

End of Beginners Digest, Vol 89, Issue 38
*****************************************



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Re: Beginners Digest, Vol 89, Issue 38 How to define a simple function

MJ Williams
In short, your types do not match in your calculation of the half of
the length of the list.  According to GHCI

length :: [a] -> Int
(/) :: Fractional a => a -> a -> a
floor :: (Integral b, RealFrac a) => a -> b

Can you see how you might run into problems with this mixed bag of types?

The only instance where you might find type compatibility between
above types would be if you were passing a value of type `Int' to a
function that accepted values of type `Integral'.  `Int', if you like,
is a subset of `Integral'

A simple solution would be to replace `/' with `div' (`div :: Integral
a => a -> a -> a').  Thus, your functionwould look something like

halve :: [a] -> [[a], [a]]
halve xs = [take longitud xs, drop longitud xs]
  where
  longitud = div (length xs) 2

Hope that helps, and don't hesitate to come back with more questions.

Matthew


On 23/11/2015, Francisco Gutierrez <[hidden email]> wrote:

> Dear sirs:I am defining a function halve, that breaks a list in two halfs.
> But I always get an error. Below is my code. What am I doing
> wrong?Thanks!halve xs = [take (floor (longitud/2)), drop (floor
> (longitud/2))]  where longitud = length xs
>
>
>       From: "[hidden email]" <[hidden email]>
>  To: [hidden email]
>  Sent: Saturday, November 21, 2015 8:21 PM
>  Subject: Beginners Digest, Vol 89, Issue 38
>
> Send Beginners mailing list submissions to
>     [hidden email]
>
> To subscribe or unsubscribe via the World Wide Web, visit
>     http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> or, via email, send a message with subject or body 'help' to
>     [hidden email]
>
> You can reach the person managing the list at
>     [hidden email]
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Beginners digest..."
>
>
> Today's Topics:
>
>   1. Re:  Warning: Tab Character (Dan Stromberg)
>   2. Re:  Warning: Tab Character (Jeon-Young Kang)
>   3. Re:  Warning: Tab Character (Thomas Jakway)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 21 Nov 2015 16:44:21 -0800
> From: Dan Stromberg <[hidden email]>
> To: The Haskell-Beginners Mailing List - Discussion of primarily
>     beginner-level topics related to Haskell <[hidden email]>
> Subject: Re: [Haskell-beginners] Warning: Tab Character
> Message-ID:
>     <[hidden email]>
> Content-Type: text/plain; charset="utf-8"
>
> I believe the first version of make required tabs, but some subsequent
> versions have relaxed that requirement to make things easier.
>
> Here's an example on a Linux Mint system (the 20's are of course spaces) :
> $ od -cx < Makefile
> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
> 0000000  \n  g  o  :  \n                  .  /  t  \n  \n
>           670a    3a6f    200a    2020    2e20    742f    0a0a
> 0000016
> above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make
> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
> Makefile:3: *** missing separator.  Stop.
> above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
> $ make --version
> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
> GNU Make 3.81
> Copyright (C) 2006  Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.
> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
> PARTICULAR PURPOSE.
>
> This program built for i686-pc-linux-gnu
> above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>
>
> I'll add that vim's Makefile syntax highlighting puts the space-indented
> line in red, suggesting an error.  Changing the spaces to a single tab
> makes the red go away.
>
> HTH
>
> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:
>
>> Why would make require tabs...?
>> Admittedly it's been a long time since I've written any makefiles by hand
>> but I always use spaces instead of tabs and have never had any problems.
>>
>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>> >
>> > Have you found "soft tabs"? That option will make TextMate use spaces
>> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs" in
>> Dan
>> Strombergs link for instrucitons.
>> >
>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>> >>
>> >> I've tried to choose "instead of spaces". But there is no option of
>> mine (Textmate 2 beta).
>> >>
>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]>
>> wrote:
>> >>>
>> >>>
>> >>> Perhaps enable soft tabs?
>> >>> https://manual.macromates.com/en/working_with_text
>> >>>
>> >>> This is an issue in Python too (at least from PEP8's perspective) -
>> but note that many "make" programs require tabs instead of spaces.
>> >>>
>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>> >>> <[hidden email]>
>> wrote:
>> >>>>
>> >>>> Hello everyone.
>> >>>>
>> >>>>
>> >>>> I am a newbie of Haskell, using Textmate on mac.
>> >>>>
>> >>>>
>> >>>> I got the following warning. How can I fix it?
>> >>>>
>> >>>>
>> >>>> Warning:
>> >>>>
>> >>>>    Tab character
>> >>>>
>> >>>> Ok, modules loaded: Main.
>> >>>>
>> >>>>
>> >>>>
>> >>>> Sincerely,
>> >>>> Young
>> >>>>
>> >>>> _______________________________________________
>> >>>> Beginners mailing list
>> >>>> [hidden email]
>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> Dan Stromberg
>> >>>
>> >>> _______________________________________________
>> >>> Beginners mailing list
>> >>> [hidden email]
>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> Department of Geography
>> >> State University of New York at Buffalo
>> >>
>> >> [hidden email]
>> >>
>> >> Jeon-Young Kang
>> >>
>> >> _______________________________________________
>> >> Beginners mailing list
>> >> [hidden email]
>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> >>
>> >
>> _______________________________________________
>> Beginners mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>
>
>
>
> --
> Dan Stromberg
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://mail.haskell.org/pipermail/beginners/attachments/20151121/bef7b6d7/attachment-0001.html>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 21 Nov 2015 20:03:08 -0500
> From: Jeon-Young Kang <[hidden email]>
> To: The Haskell-Beginners Mailing List - Discussion of primarily
>     beginner-level topics related to Haskell <[hidden email]>
> Subject: Re: [Haskell-beginners] Warning: Tab Character
> Message-ID:
>     <CALWtiK8DqDr292Bb=[hidden email]>
> Content-Type: text/plain; charset="utf-8"
>
> Thanks! I figured out.
>
> On Sat, Nov 21, 2015 at 7:44 PM, Dan Stromberg <[hidden email]> wrote:
>
>>
>> I believe the first version of make required tabs, but some subsequent
>> versions have relaxed that requirement to make things easier.
>>
>> Here's an example on a Linux Mint system (the 20's are of course spaces)
>> :
>> $ od -cx < Makefile
>> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
>> 0000000  \n  g  o  :  \n                  .  /  t  \n  \n
>>            670a    3a6f    200a    2020    2e20    742f    0a0a
>> 0000016
>> above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make
>> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
>> Makefile:3: *** missing separator.  Stop.
>> above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make --version
>> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
>> GNU Make 3.81
>> Copyright (C) 2006  Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.
>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>> PARTICULAR PURPOSE.
>>
>> This program built for i686-pc-linux-gnu
>> above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>>
>> I'll add that vim's Makefile syntax highlighting puts the space-indented
>> line in red, suggesting an error.  Changing the spaces to a single tab
>> makes the red go away.
>>
>> HTH
>>
>> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:
>>
>>> Why would make require tabs...?
>>> Admittedly it's been a long time since I've written any makefiles by
>>> hand
>>> but I always use spaces instead of tabs and have never had any problems.
>>>
>>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>>> >
>>> > Have you found "soft tabs"? That option will make TextMate use spaces
>>> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs" in
>>> Dan
>>> Strombergs link for instrucitons.
>>> >
>>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>>> >>
>>> >> I've tried to choose "instead of spaces". But there is no option of
>>> mine (Textmate 2 beta).
>>> >>
>>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]>
>>> wrote:
>>> >>>
>>> >>>
>>> >>> Perhaps enable soft tabs?
>>> >>> https://manual.macromates.com/en/working_with_text
>>> >>>
>>> >>> This is an issue in Python too (at least from PEP8's perspective) -
>>> but note that many "make" programs require tabs instead of spaces.
>>> >>>
>>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>>> >>> <[hidden email]>
>>> wrote:
>>> >>>>
>>> >>>> Hello everyone.
>>> >>>>
>>> >>>>
>>> >>>> I am a newbie of Haskell, using Textmate on mac.
>>> >>>>
>>> >>>>
>>> >>>> I got the following warning. How can I fix it?
>>> >>>>
>>> >>>>
>>> >>>> Warning:
>>> >>>>
>>> >>>>    Tab character
>>> >>>>
>>> >>>> Ok, modules loaded: Main.
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>> Sincerely,
>>> >>>> Young
>>> >>>>
>>> >>>> _______________________________________________
>>> >>>> Beginners mailing list
>>> >>>> [hidden email]
>>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>>
>>> >>>
>>> >>>
>>> >>>
>>> >>> --
>>> >>> Dan Stromberg
>>> >>>
>>> >>> _______________________________________________
>>> >>> Beginners mailing list
>>> >>> [hidden email]
>>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>
>>> >>
>>> >>
>>> >>
>>> >> --
>>> >> Department of Geography
>>> >> State University of New York at Buffalo
>>> >>
>>> >> [hidden email]
>>> >>
>>> >> Jeon-Young Kang
>>> >>
>>> >> _______________________________________________
>>> >> Beginners mailing list
>>> >> [hidden email]
>>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>
>>> >
>>> _______________________________________________
>>> Beginners mailing list
>>> [hidden email]
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>
>>
>>
>>
>> --
>> Dan Stromberg
>>
>> _______________________________________________
>> Beginners mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>
>>
>
>
> --
> Department of Geography
> State University of New York at Buffalo
>
> [hidden email]
>
> Jeon-Young Kang
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://mail.haskell.org/pipermail/beginners/attachments/20151121/efe59567/attachment-0001.html>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 21 Nov 2015 20:22:04 -0500
> From: Thomas Jakway <[hidden email]>
> To: The Haskell-Beginners Mailing List - Discussion of primarily
>     beginner-level topics related to Haskell <[hidden email]>
> Subject: Re: [Haskell-beginners] Warning: Tab Character
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=utf-8
>
> Huh, cool.  I had no idea.  Thanks!
>
> On Nov 21, 2015 7:44 PM, Dan Stromberg <[hidden email]> wrote:
>>
>>
>> I believe the first version of make required tabs, but some subsequent
>> versions have relaxed that requirement to make things easier.
>>
>> Here's an example on a Linux Mint system (the 20's are of course spaces)
>> :
>> $ od -cx < Makefile
>> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
>> 0000000? \n?? g?? o?? :? \n?????????????????? .?? /?? t? \n? \n
>> ?????????? 670a??? 3a6f??? 200a??? 2020??? 2e20??? 742f??? 0a0a
>> 0000016
>> above cmd output done??? 2015 Sat Nov 21 04:39:47 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make
>> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
>> Makefile:3: *** missing separator.? Stop.
>> above cmd output done??? 2015 Sat Nov 21 04:39:48 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make --version
>> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
>> GNU Make 3.81
>> Copyright (C) 2006? Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.
>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>> PARTICULAR PURPOSE.
>>
>> This program built for i686-pc-linux-gnu
>> above cmd output done??? 2015 Sat Nov 21 04:39:53 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>>
>> I'll add that vim's Makefile syntax highlighting puts the space-indented
>> line in red, suggesting an error.? Changing the spaces to a single tab
>> makes the red go away.
>>
>> HTH
>>
>> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]> wrote:
>>>
>>> Why would make require tabs...?
>>> Admittedly it's been a long time since I've written any makefiles by hand
>>> but I always use spaces instead of tabs and have never had any problems.
>>>
>>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>>> >
>>> > Have you found "soft tabs"? That option will make?TextMate use spaces
>>> > instead of tab characters. Read?4.11 "Using Spaces Instead of Tabs" in
>>> > Dan Strombergs link for instrucitons.
>>> >
>>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>>> >>
>>> >> I've tried to choose "instead of spaces". But there is no option of
>>> >> mine (Textmate 2 beta).
>>> >>
>>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg <[hidden email]>
>>> >> wrote:
>>> >>>
>>> >>>
>>> >>> Perhaps enable soft tabs?
>>> >>> https://manual.macromates.com/en/working_with_text
>>> >>>
>>> >>> This is an issue in Python too (at least from PEP8's perspective) -
>>> >>> but note that many "make" programs require tabs instead of spaces.
>>> >>>
>>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>>> >>> <[hidden email]> wrote:
>>> >>>>
>>> >>>> Hello everyone.
>>> >>>>
>>> >>>>
>>> >>>> I am a newbie of Haskell, using Textmate on mac.
>>> >>>>
>>> >>>>
>>> >>>> I got the following warning. How can I fix it?
>>> >>>>
>>> >>>>
>>> >>>> Warning:
>>> >>>>
>>> >>>> ? ? Tab character
>>> >>>>
>>> >>>> Ok, modules loaded: Main.
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>> Sincerely,
>>> >>>> Young
>>> >>>>
>>> >>>> _______________________________________________
>>> >>>> Beginners mailing list
>>> >>>> [hidden email]
>>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>>
>>> >>>
>>> >>>
>>> >>>
>>> >>> --
>>> >>> Dan Stromberg
>>> >>>
>>> >>> _______________________________________________
>>> >>> Beginners mailing list
>>> >>> [hidden email]
>>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>
>>> >>
>>> >>
>>> >>
>>> >> --
>>> >> Department of Geography
>>> >> State University of New York at Buffalo
>>> >>
>>> >> [hidden email]
>>> >> ?
>>> >> Jeon-Young Kang
>>> >>
>>> >> _______________________________________________
>>> >> Beginners mailing list
>>> >> [hidden email]
>>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>
>>> >
>>> _______________________________________________
>>> Beginners mailing list
>>> [hidden email]
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>
>>
>>
>>
>> --
>> Dan Stromberg
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
>
> ------------------------------
>
> End of Beginners Digest, Vol 89, Issue 38
> *****************************************
>
>
>
_______________________________________________
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Re: Beginners Digest, Vol 89, Issue 38 How to define a simple function

Gesh
On November 24, 2015 6:29:16 AM GMT+02:00, MJ Williams <[hidden email]> wrote:

>In short, your types do not match in your calculation of the half of
>the length of the list.  According to GHCI
>
>length :: [a] -> Int
>(/) :: Fractional a => a -> a -> a
>floor :: (Integral b, RealFrac a) => a -> b
>
>Can you see how you might run into problems with this mixed bag of
>types?
>
>The only instance where you might find type compatibility between
>above types would be if you were passing a value of type `Int' to a
>function that accepted values of type `Integral'.  `Int', if you like,
>is a subset of `Integral'
>
>A simple solution would be to replace `/' with `div' (`div :: Integral
>a => a -> a -> a').  Thus, your functionwould look something like
>
>halve :: [a] -> [[a], [a]]
>halve xs = [take longitud xs, drop longitud xs]
>  where
>  longitud = div (length xs) 2
>
>Hope that helps, and don't hesitate to come back with more questions.
>
>Matthew
>
>
>On 23/11/2015, Francisco Gutierrez <[hidden email]> wrote:
>> Dear sirs:I am defining a function halve, that breaks a list in two
>halfs.
>> But I always get an error. Below is my code. What am I doing
>> wrong?Thanks!halve xs = [take (floor (longitud/2)), drop (floor
>> (longitud/2))]  where longitud = length xs
>>
>>
>>       From: "[hidden email]"
><[hidden email]>
>>  To: [hidden email]
>>  Sent: Saturday, November 21, 2015 8:21 PM
>>  Subject: Beginners Digest, Vol 89, Issue 38
>>
>> Send Beginners mailing list submissions to
>>     [hidden email]
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>>     http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>> or, via email, send a message with subject or body 'help' to
>>     [hidden email]
>>
>> You can reach the person managing the list at
>>     [hidden email]
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Beginners digest..."
>>
>>
>> Today's Topics:
>>
>>   1. Re:  Warning: Tab Character (Dan Stromberg)
>>   2. Re:  Warning: Tab Character (Jeon-Young Kang)
>>   3. Re:  Warning: Tab Character (Thomas Jakway)
>>
>>
>>
>----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 21 Nov 2015 16:44:21 -0800
>> From: Dan Stromberg <[hidden email]>
>> To: The Haskell-Beginners Mailing List - Discussion of primarily
>>     beginner-level topics related to Haskell <[hidden email]>
>> Subject: Re: [Haskell-beginners] Warning: Tab Character
>> Message-ID:
>>    
><[hidden email]>
>> Content-Type: text/plain; charset="utf-8"
>>
>> I believe the first version of make required tabs, but some
>subsequent
>> versions have relaxed that requirement to make things easier.
>>
>> Here's an example on a Linux Mint system (the 20's are of course
>spaces) :
>> $ od -cx < Makefile
>> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
>> 0000000  \n  g  o  :  \n                  .  /  t  \n  \n
>>           670a    3a6f    200a    2020    2e20    742f    0a0a
>> 0000016
>> above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make
>> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
>> Makefile:3: *** missing separator.  Stop.
>> above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>> $ make --version
>> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
>> GNU Make 3.81
>> Copyright (C) 2006  Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.
>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>> PARTICULAR PURPOSE.
>>
>> This program built for i686-pc-linux-gnu
>> above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>
>>
>> I'll add that vim's Makefile syntax highlighting puts the
>space-indented
>> line in red, suggesting an error.  Changing the spaces to a single
>tab
>> makes the red go away.
>>
>> HTH
>>
>> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]>
>wrote:
>>
>>> Why would make require tabs...?
>>> Admittedly it's been a long time since I've written any makefiles by
>hand
>>> but I always use spaces instead of tabs and have never had any
>problems.
>>>
>>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>>> >
>>> > Have you found "soft tabs"? That option will make TextMate use
>spaces
>>> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs"
>in
>>> Dan
>>> Strombergs link for instrucitons.
>>> >
>>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>>> >>
>>> >> I've tried to choose "instead of spaces". But there is no option
>of
>>> mine (Textmate 2 beta).
>>> >>
>>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg
><[hidden email]>
>>> wrote:
>>> >>>
>>> >>>
>>> >>> Perhaps enable soft tabs?
>>> >>> https://manual.macromates.com/en/working_with_text
>>> >>>
>>> >>> This is an issue in Python too (at least from PEP8's
>perspective) -
>>> but note that many "make" programs require tabs instead of spaces.
>>> >>>
>>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>>> >>> <[hidden email]>
>>> wrote:
>>> >>>>
>>> >>>> Hello everyone.
>>> >>>>
>>> >>>>
>>> >>>> I am a newbie of Haskell, using Textmate on mac.
>>> >>>>
>>> >>>>
>>> >>>> I got the following warning. How can I fix it?
>>> >>>>
>>> >>>>
>>> >>>> Warning:
>>> >>>>
>>> >>>>    Tab character
>>> >>>>
>>> >>>> Ok, modules loaded: Main.
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>> Sincerely,
>>> >>>> Young
>>> >>>>
>>> >>>> _______________________________________________
>>> >>>> Beginners mailing list
>>> >>>> [hidden email]
>>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>>
>>> >>>
>>> >>>
>>> >>>
>>> >>> --
>>> >>> Dan Stromberg
>>> >>>
>>> >>> _______________________________________________
>>> >>> Beginners mailing list
>>> >>> [hidden email]
>>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>>
>>> >>
>>> >>
>>> >>
>>> >> --
>>> >> Department of Geography
>>> >> State University of New York at Buffalo
>>> >>
>>> >> [hidden email]
>>> >>
>>> >> Jeon-Young Kang
>>> >>
>>> >> _______________________________________________
>>> >> Beginners mailing list
>>> >> [hidden email]
>>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>> >>
>>> >
>>> _______________________________________________
>>> Beginners mailing list
>>> [hidden email]
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>
>>
>>
>>
>> --
>> Dan Stromberg
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL:
>>
><http://mail.haskell.org/pipermail/beginners/attachments/20151121/bef7b6d7/attachment-0001.html>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 21 Nov 2015 20:03:08 -0500
>> From: Jeon-Young Kang <[hidden email]>
>> To: The Haskell-Beginners Mailing List - Discussion of primarily
>>     beginner-level topics related to Haskell <[hidden email]>
>> Subject: Re: [Haskell-beginners] Warning: Tab Character
>> Message-ID:
>>    
><CALWtiK8DqDr292Bb=[hidden email]>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Thanks! I figured out.
>>
>> On Sat, Nov 21, 2015 at 7:44 PM, Dan Stromberg <[hidden email]>
>wrote:
>>
>>>
>>> I believe the first version of make required tabs, but some
>subsequent
>>> versions have relaxed that requirement to make things easier.
>>>
>>> Here's an example on a Linux Mint system (the 20's are of course
>spaces)
>>> :
>>> $ od -cx < Makefile
>>> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
>>> 0000000  \n  g  o  :  \n                  .  /  t  \n  \n
>>>            670a    3a6f    200a    2020    2e20    742f    0a0a
>>> 0000016
>>> above cmd output done    2015 Sat Nov 21 04:39:47 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>> $ make
>>> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
>>> Makefile:3: *** missing separator.  Stop.
>>> above cmd output done    2015 Sat Nov 21 04:39:48 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>> $ make --version
>>> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
>>> GNU Make 3.81
>>> Copyright (C) 2006  Free Software Foundation, Inc.
>>> This is free software; see the source for copying conditions.
>>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>>> PARTICULAR PURPOSE.
>>>
>>> This program built for i686-pc-linux-gnu
>>> above cmd output done    2015 Sat Nov 21 04:39:53 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>>
>>> I'll add that vim's Makefile syntax highlighting puts the
>space-indented
>>> line in red, suggesting an error.  Changing the spaces to a single
>tab
>>> makes the red go away.
>>>
>>> HTH
>>>
>>> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]>
>wrote:
>>>
>>>> Why would make require tabs...?
>>>> Admittedly it's been a long time since I've written any makefiles
>by
>>>> hand
>>>> but I always use spaces instead of tabs and have never had any
>problems.
>>>>
>>>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>>>> >
>>>> > Have you found "soft tabs"? That option will make TextMate use
>spaces
>>>> instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs"
>in
>>>> Dan
>>>> Strombergs link for instrucitons.
>>>> >
>>>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>>>> >>
>>>> >> I've tried to choose "instead of spaces". But there is no option
>of
>>>> mine (Textmate 2 beta).
>>>> >>
>>>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg
><[hidden email]>
>>>> wrote:
>>>> >>>
>>>> >>>
>>>> >>> Perhaps enable soft tabs?
>>>> >>> https://manual.macromates.com/en/working_with_text
>>>> >>>
>>>> >>> This is an issue in Python too (at least from PEP8's
>perspective) -
>>>> but note that many "make" programs require tabs instead of spaces.
>>>> >>>
>>>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>>>> >>> <[hidden email]>
>>>> wrote:
>>>> >>>>
>>>> >>>> Hello everyone.
>>>> >>>>
>>>> >>>>
>>>> >>>> I am a newbie of Haskell, using Textmate on mac.
>>>> >>>>
>>>> >>>>
>>>> >>>> I got the following warning. How can I fix it?
>>>> >>>>
>>>> >>>>
>>>> >>>> Warning:
>>>> >>>>
>>>> >>>>    Tab character
>>>> >>>>
>>>> >>>> Ok, modules loaded: Main.
>>>> >>>>
>>>> >>>>
>>>> >>>>
>>>> >>>> Sincerely,
>>>> >>>> Young
>>>> >>>>
>>>> >>>> _______________________________________________
>>>> >>>> Beginners mailing list
>>>> >>>> [hidden email]
>>>> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>> >>>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>> --
>>>> >>> Dan Stromberg
>>>> >>>
>>>> >>> _______________________________________________
>>>> >>> Beginners mailing list
>>>> >>> [hidden email]
>>>> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>> >>>
>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Department of Geography
>>>> >> State University of New York at Buffalo
>>>> >>
>>>> >> [hidden email]
>>>> >>
>>>> >> Jeon-Young Kang
>>>> >>
>>>> >> _______________________________________________
>>>> >> Beginners mailing list
>>>> >> [hidden email]
>>>> >> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>> >>
>>>> >
>>>> _______________________________________________
>>>> Beginners mailing list
>>>> [hidden email]
>>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>>
>>>
>>>
>>>
>>> --
>>> Dan Stromberg
>>>
>>> _______________________________________________
>>> Beginners mailing list
>>> [hidden email]
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>>>
>>>
>>
>>
>> --
>> Department of Geography
>> State University of New York at Buffalo
>>
>> [hidden email]
>>
>> Jeon-Young Kang
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL:
>>
><http://mail.haskell.org/pipermail/beginners/attachments/20151121/efe59567/attachment-0001.html>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Sat, 21 Nov 2015 20:22:04 -0500
>> From: Thomas Jakway <[hidden email]>
>> To: The Haskell-Beginners Mailing List - Discussion of primarily
>>     beginner-level topics related to Haskell <[hidden email]>
>> Subject: Re: [Haskell-beginners] Warning: Tab Character
>> Message-ID: <[hidden email]>
>> Content-Type: text/plain; charset=utf-8
>>
>> Huh, cool.  I had no idea.  Thanks!
>>
>> On Nov 21, 2015 7:44 PM, Dan Stromberg <[hidden email]> wrote:
>>>
>>>
>>> I believe the first version of make required tabs, but some
>subsequent
>>> versions have relaxed that requirement to make things easier.
>>>
>>> Here's an example on a Linux Mint system (the 20's are of course
>spaces)
>>> :
>>> $ od -cx < Makefile
>>> cmd output started 2015 Sat Nov 21 04:39:47 PM PST
>>> 0000000? \n?? g?? o?? :? \n?????????????????? .?? /?? t? \n? \n
>>> ?????????? 670a??? 3a6f??? 200a??? 2020??? 2e20??? 742f??? 0a0a
>>> 0000016
>>> above cmd output done??? 2015 Sat Nov 21 04:39:47 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>> $ make
>>> cmd output started 2015 Sat Nov 21 04:39:48 PM PST
>>> Makefile:3: *** missing separator.? Stop.
>>> above cmd output done??? 2015 Sat Nov 21 04:39:48 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>> $ make --version
>>> cmd output started 2015 Sat Nov 21 04:39:53 PM PST
>>> GNU Make 3.81
>>> Copyright (C) 2006? Free Software Foundation, Inc.
>>> This is free software; see the source for copying conditions.
>>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>>> PARTICULAR PURPOSE.
>>>
>>> This program built for i686-pc-linux-gnu
>>> above cmd output done??? 2015 Sat Nov 21 04:39:53 PM PST
>>> dstromberg@dell-inspiron:/var/tmp/make-tabs i686-pc-linux-gnu 25234
>>>
>>>
>>> I'll add that vim's Makefile syntax highlighting puts the
>space-indented
>>> line in red, suggesting an error.? Changing the spaces to a single
>tab
>>> makes the red go away.
>>>
>>> HTH
>>>
>>> On Sat, Nov 21, 2015 at 3:34 PM, Thomas Jakway <[hidden email]>
>wrote:
>>>>
>>>> Why would make require tabs...?
>>>> Admittedly it's been a long time since I've written any makefiles
>by hand
>>>> but I always use spaces instead of tabs and have never had any
>problems.
>>>>
>>>> On Nov 21, 2015 6:01 PM, David Moberg <[hidden email]> wrote:
>>>> >
>>>> > Have you found "soft tabs"? That option will make?TextMate use
>spaces
>>>> > instead of tab characters. Read?4.11 "Using Spaces Instead of
>Tabs" in
>>>> > Dan Strombergs link for instrucitons.
>>>> >
>>>> > 2015-11-21 21:36 GMT+01:00 Jeon-Young Kang <[hidden email]>:
>>>> >>
>>>> >> I've tried to choose "instead of spaces". But there is no option
>of
>>>> >> mine (Textmate 2 beta).
>>>> >>
>>>> >> On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg
><[hidden email]>
>>>> >> wrote:
>>>> >>>
>>>> >>>
>>>> >>> Perhaps enable soft tabs?
>>>> >>> https://manual.macromates.com/en/working_with_text
>>>> >>>
>>>> >>> This is an issue in Python too (at least from PEP8's
>perspective) -
>>>> >>> but note that many "make" programs require tabs instead of
>spaces.
>>>> >>>
>>>> >>> On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang
>>>> >>> <[hidden email]> wrote:
>>>> >>>>
>>>> >>>> Hello everyone.
>>>> >>>>
>>>> >>>>
>>>> >>>> I am a newbie of Haskell, using Textmate on mac.
>>>> >>>>
>>>> >>>>
>>>> >>>> I got the following warning. How can I fix it?
>>>> >>>>
>>>> >>>>
>>>> >>>> Warning:
>>>> >>>>
>>>> >>>> ? ? Tab character
>>>> >>>>
>>>> >>>> Ok, modules loaded: Main.
>>>> >>>>
>>>> >>>>
>>>> >>>>
>>>> >>>> Sincerely,
>>>> >>>> Young
>>>> >>>>
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>>>> >>>
>>>> >>>
>>>> >>> --
>>>> >>> Dan Stromberg
>>>> >>>
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>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Department of Geography
>>>> >> State University of New York at Buffalo
>>>> >>
>>>> >> [hidden email]
>>>> >> ?
>>>> >> Jeon-Young Kang
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>>>
>>> --
>>> Dan Stromberg
>>
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Of course, besides the numerical hierarchy problems,
you also have a type incompatibility because you didn't apply take and drop to enough arguments.
i.e. take (length xs `div` 2) :: [a] -> [a], whereas you seem to want take (length xs `div` 2) xs :: [a].

Also, note that you could rewrite your code to make
use of the commonality of your arguments, so it becomes:
> halve xs = map ($xs) . map ($ (length xs `div` 2)) $ [take, drop]
(Untested, but it should work. Only possible problem I can see is that the (length xs `div` 2) section might be illegal)
Sing map f . map g = map (f.g), we can rewrite this to:
> halve xs = map (\f -> f (length xs `div` 2) xs) [take, drop]

HTH,
Gesh
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