On November 24, 2015 6:29:16 AM GMT+02:00, MJ Williams 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 wrote:

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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: "beginners-request@haskell.org" To: beginners@haskell.org Sent: Saturday, November 21, 2015 8:21 PM Subject: Beginners Digest, Vol 89, Issue 38

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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)

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Message: 1 Date: Sat, 21 Nov 2015 16:44:21 -0800 From: Dan Stromberg To: The Haskell-Beginners Mailing List - Discussion of primarily     beginner-level topics related to Haskell Subject: Re: [Haskell-beginners] Warning: Tab Character Message-ID:    

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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 wrote:

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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

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On Nov 21, 2015 6:01 PM, David Moberg wrote:

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Have you found "soft tabs"? That option will make TextMate use

spaces

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instead of tab characters. Read 4.11 "Using Spaces Instead of Tabs" in Dan Strombergs link for instrucitons.

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2015-11-21 21:36 GMT+01:00 Jeon-Young Kang :

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I've tried to choose "instead of spaces". But there is no option

of mine (Textmate 2 beta).

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On Sat, Nov 21, 2015 at 3:14 PM, Dan Stromberg

wrote:

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Perhaps enable soft tabs? https://manual.macromates.com/en/working_with_text

This is an issue in Python too (at least from PEP8's

problems. perspective) -

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but note that many "make" programs require tabs instead of spaces.

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On Sat, Nov 21, 2015 at 11:13 AM, Jeon-Young Kang

wrote:

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> > 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 > Beginners@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners >

-- Dan Stromberg

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

jykang22@gmail.com

Jeon-Young Kang

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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-- Dan Stromberg