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Today's Topics:
1. Re: trying to install libraries for Haskell School of
Expression (Brandon Allbery)
2. Re: trees on Haskell : Do I understand it right ?
(Magnus Therning)
----------------------------------------------------------------------
Message: 1
Date: Sun, 1 Mar 2015 02:29:54 -0500
From: Brandon Allbery <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] trying to install libraries for
Haskell School of Expression
Message-ID:
<cakfcl4urz9tr-snqwnexa_igzg5z1-xpa6xijtnswrjjeww...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
On Sat, Feb 28, 2015 at 11:40 PM, DJ <[email protected]> wrote:
> I am running linux mint 17 with the latest (as of Feb. 28) haskell
> platform and cabal-install.
> I did install gtk2hs-buildtools and put the .cabal/bin in my path.
>
Do you have the devel libraries needed by gtk installed? cabal cannot
install them for you, and the runtime libraries are not sufficient. You'll
want libcairo2-dev for this, and others for other gtk components (notably
libgtk-3-dev but there will be others as well).
--
brandon s allbery kf8nh sine nomine associates
[email protected] [email protected]
unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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Message: 2
Date: Sun, 1 Mar 2015 09:30:35 +0100
From: Magnus Therning <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] trees on Haskell : Do I understand it
right ?
Message-ID: <20150301083035.GA3078@tatooine>
Content-Type: text/plain; charset="utf-8"
Roelof, please consider changing your mail client to send *both* HTML
and plain-text emails! With your current setting you send *only* HTML
sometimes and it results in a slightly broken list archive, see [1]
for an example of the result.
To boot, you also make it more difficult for those of us who use
plain-text mail clients to benefit from the diskussions you
participate in.
/M
[1]: https://mail.haskell.org/pipermail/beginners/2015-February/014808.html
On Thu, Feb 26, 2015 at 03:01:22PM +0100, Roelof Wobben wrote:
> <html>
> <head>
> <meta content="text/html; charset=windows-1252"
> http-equiv="Content-Type">
> </head>
> <body bgcolor="#FFFFFF" text="#000000">
> <div class="moz-cite-prefix">Oke, <br>
> <br>
> So a leaf is a node which has no "branch"<br>
> <br>
> I have made a exercise where I have to made the? logMessages. <br>
> Now I have to turn them into a tree <br>
> <br>
> Where does the second entry goes then ?<br>
> <br>
> Roelof<br>
> <br>
> <br>
> Konstantine Rybnikov schreef op 26-2-2015 om 14:56:<br>
> </div>
> <blockquote
> cite="mid:caabahfqo5o+db_qy_b+vb3e6wwb1bdeqbmpapa6e-5twtje...@mail.gmail.com"
> type="cite">
> <div dir="ltr">
> <div>
> <div>
> <div>
> <div>
> <div>
> <div>
> <div>Hi Roelof,<br>
> <br>
> </div>
> I think you misunderstood it.<br>
> <br>
> </div>
> <div>There are two things here: types and values
> (value-constructors). They exist in different world,
> not touching each other.<br>
> <br>
> </div>
> <div>In Haskell, you define a type as:<br>
> <br>
> </div>
> <div>data <Type_Name> =
> <ValueConstructor_Name> <Type_Name>
> <Type_Name> <Type_Name><br>
> <br>
> </div>
> <div>You can create values as:<br>
> <br>
> </div>
> <div>let varName = <ValueConstructor_Name>
> <Value> <Value> <Value><br>
> <br>
> </div>
> <div>You need to put <Value> of some type, not
> type name itself in place of those <Value>s.<br>
> <br>
> </div>
> <div>So, with datatype you provided, you have two
> data-constructors:<br>
> <br>
> </div>
> <div>Leaf<br>
> <br>
> </div>
> <div>and<br>
> <br>
> </div>
> <div>Node <val> <val> <val><br>
> <br>
> </div>
> <div>You can create a leaf:<br>
> <br>
> </div>
> <div>let leaf = Leav<br>
> <br>
> </div>
> <div>or a node:<br>
> <br>
> </div>
> <div>let node = Node Leaf "msg" Leaf<br>
> <br>
> </div>
> <div>You can see that Node is a data-constructor that
> takes 3 values, not type-names as it's parameters.<br>
> <br>
> </div>
> <div>Hope this helps.<br>
> </div>
> </div>
> </div>
> </div>
> </div>
> </div>
> </div>
> <div class="gmail_extra"><br>
> <div class="gmail_quote">On Thu, Feb 26, 2015 at 3:21 PM, Roelof
> Wobben <span dir="ltr"><<a moz-do-not-send="true"
> href="mailto:[email protected]";
> target="_blank">[email protected]</a>></span>
> wrote:<br>
> <blockquote class="gmail_quote" style="margin:0 0 0
> .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
> <br>
> Suppose we have this definition of a tree :<br>
> <br>
> data MessageTree = Leaf<br>
> ? ? ? ? ? ? ? ? ?| Node MessageTree LogMessage MessageTree<br>
> ? deriving (Show, Eq)<br>
> <br>
> let Message? = LogMessage "E 1 this is a test error"<br>
> let Message = LogMessage "e 2 this is the second test error
> "<br>
> <br>
> As I understand it right I can make the first entry like
> this : first_entry = Node Messagetree? Message Messagetree<br>
> <br>
> And the second one like this second_entry = Node Message
> Messagetree Message2 Messagetree ??<br>
> <br>
> Roelof<br>
> <br>
> _______________________________________________<br>
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> </blockquote>
> </div>
> <br>
> </div>
> <br>
> <fieldset class="mimeAttachmentHeader"></fieldset>
> <br>
> <pre wrap="">_______________________________________________
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--
Magnus Therning OpenPGP: 0xAB4DFBA4
email: [email protected] jabber: [email protected]
twitter: magthe http://therning.org/magnus
Heuristic is an algorithm in a clown suit. It?s less predictable, it?s more
fun, and it comes without a 30-day, money-back guarantee.
-- Steve McConnell, Code Complete
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