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Today's Topics:
1. Re: Re: proper way to read fold types (Brandon S Allbery KF8NH)
2. playing around with code from the tutorials for Yesod - and
this came up. (Michael Litchard)
3. Re: playing around with code from the tutorials for Yesod -
and this came up. (Michael Litchard)
----------------------------------------------------------------------
Message: 1
Date: Mon, 26 Jul 2010 11:16:37 -0400
From: Brandon S Allbery KF8NH <allb...@ece.cmu.edu>
Subject: Re: [Haskell-beginners] Re: proper way to read fold types
To: beginners@haskell.org
Message-ID: <4c4da6d5.8080...@ece.cmu.edu>
Content-Type: text/plain; charset=UTF-8
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On 7/26/10 07:30 , dan portin wrote:
> I'm still a Haskell newbie, so take this with a grain of salt: the type
> signature of /foldr/ and /foldr1/ confuses me also. While I understand how
> each operates, I've never found a description of the type signatures of
> either functions which explains why the function argument of /foldr1/ is of
> type (a -> a -> a) instead of (a -> b -> b). This is the conclusion I came
foldr1 is just foldr where "z" is taken off the end of the list. Therefore,
given [a] as the list type, b (the type of z) unifies with a; and since the
folding function is initially called with z along with the first element of
the list, (a -> b -> b), in the case of foldr1 it is forced to (a -> a -> a).
- --
brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com
system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu
electrical and computer engineering, carnegie mellon university KF8NH
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Message: 2
Date: Mon, 26 Jul 2010 08:57:24 -0700
From: Michael Litchard <mich...@schmong.org>
Subject: [Haskell-beginners] playing around with code from the
tutorials for Yesod - and this came up.
To: beginners@haskell.org
Message-ID:
<aanlktinunhp-8inakubh95ogxk502a9sfkntn94kw...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
This code I am using can be seen from this url.
http://docs.yesodweb.com/yesod/tutorial/ajax.html
I downloaded it from the site, tried to compile and got this error.
ajax.lhs:55:29: Not in scope: `style_css'
ajax.lhs:55:29: Not in scope: `script_js'
Here is line 55
> hamletToContent [$hamlet|
I'm lost when it comes to figuring out why this won't compile? Changes
in interface since the tutorial was written maybe?
Any help would be greatly appreciated.
------------------------------
Message: 3
Date: Mon, 26 Jul 2010 09:45:09 -0700
From: Michael Litchard <mich...@schmong.org>
Subject: [Haskell-beginners] Re: playing around with code from the
tutorials for Yesod - and this came up.
To: beginners@haskell.org
Message-ID:
<aanlktimgrbizq3km1agls=egrpnv=uff9adeuyd0z...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Not sure what I did, but it compiles now. Thanks to Michael Snoyman
for making Yesod. :)
On Mon, Jul 26, 2010 at 8:57 AM, Michael Litchard <mich...@schmong.org> wrote:
> This code I am using can be seen from this url.
>
> http://docs.yesodweb.com/yesod/tutorial/ajax.html
>
> I downloaded it from the site, tried to compile and got this error.
>
> ajax.lhs:55:29: Not in scope: `style_css'
>
> ajax.lhs:55:29: Not in scope: `script_js'
>
>
> Here is line 55
>> hamletToContent [$hamlet|
>
> I'm lost when it comes to figuring out why this won't compile? Changes
> in interface since the tutorial was written maybe?
>
> Any help would be greatly appreciated.
>
------------------------------
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