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Today's Topics:
1. Re: Looking for some pro bono haskell work (Ertugrul Soeylemez)
2. happstack versus yesod (Ramy Abdel-Azim)
3. Re: happstack versus yesod (Alexey G)
4. Tuples .vs Either Vs datatypes (Mike Meyer)
5. Re: Tuples .vs Either Vs datatypes (Alex Rozenshteyn)
6. Re: Tuples .vs Either Vs datatypes (MAN)
----------------------------------------------------------------------
Message: 1
Date: Tue, 5 Apr 2011 19:12:30 +0200
From: Ertugrul Soeylemez <e...@ertes.de>
Subject: Re: [Haskell-beginners] Looking for some pro bono haskell
work
To: beginners@haskell.org
Message-ID: <20110405191230.03423...@angst.streitmacht.eu>
Content-Type: text/plain; charset=US-ASCII
Hello Ramy,
Yesod is a tightly integrated web framework, while Happstack is more
like a set of libraries for web development. The main difference is
that Happstack uses normal Haskell approaches to everything and allows
you to use individual components easily, while the idea of Yesod is to
add more integration and some own language (by Template Haskell and
quasi-quoting) to allow you to write less code.
You can be very productive with both of them. If you want more freedom,
use Happstack. If you want more integration, use Yesod. Personally I
found myself to have shorter development cycles with Yesod, but it has a
steep learning curve, because you need to understand Haskell and a few
of its extensions well to use it.
That's just my opinion, by the way. Others may have made different
experiences.
Greets,
Ertugrul
Ramy Abdel-Azim <ramy.abdela...@gmail.com> wrote:
> Maybe i should start a new thread here ( i certainly don't want to derail
> the conversation too much) but could someone explain the differences between
> happstack and yesod? Also, i've been thinking of getting my hands dirtier
> with haskell and trying to possibly create a webiste in Haskell. What are
> the strengths and weaknesses of each?
> Thanks,
> _Ramy
>
> On Tue, Apr 5, 2011 at 12:34 PM, aditya siram <aditya.si...@gmail.com>wrote:
>
> > I'm no Haskell guru, but I don't know any category theory and it
> > hasn't been a major stumbling block for me. I think you get a long
> > ways with Haskell before you need to go there.
> > -deech
> >
> > On Tue, Apr 5, 2011 at 9:04 AM, Patrick Lynch <kmandpjly...@verizon.net>
> > wrote:
> > > ...one more project...
> > >
> > > I tried to understand Category Theory but was unable to do so...
> > > I tried reading three books in regard to it and can understand the
> > > definition of Category...but couldn't follow any of these books past the
> > > first chapter and was unable to do any of the exercises in them...
> > > However, I did see a few links that 'graphically' showed a Category and
> > > another that showed some categories and how they were implemented in
> > Haskell
> > > - these made the most sense to me...
> > > Since categories are the basis for Functors, Monoids and Monads - which
> > are
> > > extensively used in Haskell and implicitly used, I think, in Linq - I
> > would
> > > be very willing to participate in a project that showed categories and
> > how
> > > they are implemented in Haskell...
> > >
> > > Just a thought...
> > >
> > > Ps
> > > I am an independent software consultant [been doing it for 30+ years].
> > > I did a market evaluation of Haskell and Linq and found the following:
> > > - there are page after page of Ling/C# jobs...
> > > - I only saw 1 Haskell job...
> > > It 'begs the question': is some commercial organization going to
> > implement
> > > Haskell as a product [I don't think it will be Microsoft, since they have
> > > introduced F#]...
> > >
> > > ----- Original Message ----- From: "Patrick Lynch"
> > > <kmandpjly...@verizon.net>
> > > To: "aditya siram" <aditya.si...@gmail.com>
> > > Cc: <beginners@haskell.org>
> > > Sent: Tuesday, April 05, 2011 9:45 AM
> > > Subject: Re: [Haskell-beginners] Looking for some pro bono haskell work
> > >
> > >
> > >> Good morning,
> > >> Thanks for the advice.
> > >> I sent an email to Zvon and volunteered to help them with the examples
> > of
> > >> Haskell functions in their "Haskell Reference Page"
> > >> The projects that I envisage are:
> > >> - I tried to get TK installed but was unable to do so, if someone is
> > >> working this install, I would be willing to test it for them...
> > >> - If anyone is working on a web front-end to Haskell, I would be
> > >> willing to participate...
> > >> Good day
> > >>
> > >> ----- Original Message ----- From: "aditya siram" <
> > aditya.si...@gmail.com>
> > >> To: "Patrick Lynch" <kmandpjly...@verizon.net>
> > >> Cc: <beginners@haskell.org>
> > >> Sent: Monday, April 04, 2011 5:19 PM
> > >> Subject: Re: [Haskell-beginners] Looking for some pro bono haskell work
> > >>
> > >>
> > >>> I would pick a project and contribute a patch to it, or start one of
> > your
> > >>> own.
> > >>> -deech
> > >>>
> > >>> On Mon, Apr 4, 2011 at 4:17 PM, Patrick Lynch <
> > kmandpjly...@verizon.net>
> > >>> wrote:
> > >>>>
> > >>>> Good afternoon,
> > >>>> I've read all the books and am looking for some pro bono Haskell
> > >>>> Development
> > >>>> work...
> > >>>> If you have some, please email me...
> > >>>> Thanks
> > >>>> _______________________________________________
> > >>>> Beginners mailing list
> > >>>> Beginners@haskell.org
> > >>>> http://www.haskell.org/mailman/listinfo/beginners
> > >>>>
> > >>>>
> > >>>
> > >>
> > >>
> > >> _______________________________________________
> > >> Beginners mailing list
> > >> Beginners@haskell.org
> > >> http://www.haskell.org/mailman/listinfo/beginners
> > >>
> > >
> > >
> >
> > _______________________________________________
> > Beginners mailing list
> > Beginners@haskell.org
> > http://www.haskell.org/mailman/listinfo/beginners
> >
>
--
nightmare = unsafePerformIO (getWrongWife >>= sex)
http://ertes.de/
------------------------------
Message: 2
Date: Tue, 5 Apr 2011 13:24:59 -0400
From: Ramy Abdel-Azim <ramy.abdela...@gmail.com>
Subject: [Haskell-beginners] happstack versus yesod
To: beginners@haskell.org
Message-ID: <banlktim4nz2rruiw4kz-rtyskaxep7t...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
I already posted about this a little bit but i think i should let the old
thread get back to it's regularly scheduled conversaion. on to my question:
So I know there are a million easier ways to createa blog (wordpress,
django, drupal, etc. etc.) but which would you recommend I use to build a
beginner website that is simliar to a blog: happstack or yesod?
_Ramy
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Message: 3
Date: Tue, 5 Apr 2011 20:35:40 +0300
From: Alexey G <kreed...@gmail.com>
Subject: Re: [Haskell-beginners] happstack versus yesod
To: beginners@haskell.org
Message-ID: <BANLkTikfz5iFjqO=LvuoewHpP6j=ida...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hello. It's very interesting theme for me and I want to express my opinion.
Yesod - very fast web-framework(
http://www.yesodweb.com/blog/preliminary-warp-cross-language-benchmarks).
But I don't like Yesod, because idea of Happstack more interesting for me.
Happstack gives to you some freedom.
I trying to use Snap Framework now. And it's very good for me. Try it
http://snapframework.com/!
Sorry for my english.
2011/4/5 Ramy Abdel-Azim <ramy.abdela...@gmail.com>
> I already posted about this a little bit but i think i should let the old
> thread get back to it's regularly scheduled conversaion. on to my question:
>
> So I know there are a million easier ways to createa blog (wordpress,
> django, drupal, etc. etc.) but which would you recommend I use to build a
> beginner website that is simliar to a blog: happstack or yesod?
> _Ramy
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://www.haskell.org/mailman/listinfo/beginners
>
>
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Message: 4
Date: Tue, 5 Apr 2011 13:41:07 -0400
From: Mike Meyer <m...@mired.org>
Subject: [Haskell-beginners] Tuples .vs Either Vs datatypes
To: beginners@haskell.org
Message-ID: <20110405134107.65477...@bhuda.mired.org>
Content-Type: text/plain; charset=US-ASCII
One of the exercises in Real World Haskell is to write a glob matcher
without translating it to regular expressions. This turns out to be a
lot more subtle than it looks (character classes like [!]-}] tend to
break things).
In doing this, I wrote a matchCharClass function for handling
character classes. The initial version had type:
matchCharClass :: Pattern -> Char -> (Bool, Pattern)
I.e. - it returned rest of pattern after the char class as well as a
match succeed/fail indicator. Upon reflection, I realized that only
one of the two was ever used, so rewrote it to be:
matchCharClass :: Pattern -> Char -> Either Bool Pattern
This made the calling code a little larger - taking a apart tuples is
a bit easier than taking apart Either's - but simplified the values
being generated. I then realized that the code only used one of the
Bool values: if it was True, then Pattern got used instead. So I
rewrote it a third time, giving:
data CharClass = Fail | Pattern String
matchCharClass :: Pattern -> Char -> CharClass
This only required minor changes to the code, but made it easy to add
"Error String" to the CharClass datatype later. That version can be
seen at http://pastebin.com/eyre8795 (as always, critiques welcome).
I'd like to hear what more experienced haskell programmers have to say
about those three ways of returning multiple values.
Thanks,
<mike
--
Mike Meyer <m...@mired.org> http://www.mired.org/consulting.html
Independent Software developer/SCM consultant, email for more information.
O< ascii ribbon campaign - stop html mail - www.asciiribbon.org
------------------------------
Message: 5
Date: Tue, 5 Apr 2011 14:01:30 -0400
From: Alex Rozenshteyn <rpglove...@gmail.com>
Subject: Re: [Haskell-beginners] Tuples .vs Either Vs datatypes
To: Mike Meyer <m...@mired.org>
Cc: beginners@haskell.org
Message-ID: <BANLkTi=3y3ybyr+rrcszjwwarqdcneq...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Sounds like a Maybe to me...
On Tue, Apr 5, 2011 at 1:41 PM, Mike Meyer <m...@mired.org> wrote:
> One of the exercises in Real World Haskell is to write a glob matcher
> without translating it to regular expressions. This turns out to be a
> lot more subtle than it looks (character classes like [!]-}] tend to
> break things).
>
> In doing this, I wrote a matchCharClass function for handling
> character classes. The initial version had type:
>
> matchCharClass :: Pattern -> Char -> (Bool, Pattern)
>
> I.e. - it returned rest of pattern after the char class as well as a
> match succeed/fail indicator. Upon reflection, I realized that only
> one of the two was ever used, so rewrote it to be:
>
> matchCharClass :: Pattern -> Char -> Either Bool Pattern
>
> This made the calling code a little larger - taking a apart tuples is
> a bit easier than taking apart Either's - but simplified the values
> being generated. I then realized that the code only used one of the
> Bool values: if it was True, then Pattern got used instead. So I
> rewrote it a third time, giving:
>
> data CharClass = Fail | Pattern String
> matchCharClass :: Pattern -> Char -> CharClass
>
> This only required minor changes to the code, but made it easy to add
> "Error String" to the CharClass datatype later. That version can be
> seen at http://pastebin.com/eyre8795 (as always, critiques welcome).
>
> I'd like to hear what more experienced haskell programmers have to say
> about those three ways of returning multiple values.
>
> Thanks,
> <mike
> --
> Mike Meyer <m...@mired.org>
> http://www.mired.org/consulting.html
> Independent Software developer/SCM consultant, email for more information.
>
> O< ascii ribbon campaign - stop html mail - www.asciiribbon.org
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://www.haskell.org/mailman/listinfo/beginners
>
--
Alex R
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Message: 6
Date: Tue, 05 Apr 2011 15:04:30 -0300
From: MAN <elviotoccal...@gmail.com>
Subject: Re: [Haskell-beginners] Tuples .vs Either Vs datatypes
To: Mike Meyer <m...@mired.org>
Cc: beginners@haskell.org
Message-ID: <1302026670.2272.25.camel@dy-book>
Content-Type: text/plain; charset="UTF-8"
I, for one, have a simplified view of the three that often proves
helpful for fast decisions:
- tuples are a sort of quick-and-dirty tool that gets the job done
(simple to code, accessors and constructor already there). They don't
stand well for refactoring and maintenance.
- A simple, custom datatype like yours is more explicit, easier to read
(later, after you wrote the program), and flexible. It requires bit more
code to write, and names (good names, please!) thought out.
- Apart from being a good container, Either has an Monad instance
written for you. It allows data-on-the-side :). This can prove
incredibly valuable in *some* situations. Think through if it's worth it
(it can cripple your code if your not sure about the "shape" data should
take).
I hope I'm expressing clearly enough (this subject borders
subjectivity).
El mar, 05-04-2011 a las 13:41 -0400, Mike Meyer escribi?:
> One of the exercises in Real World Haskell is to write a glob matcher
> without translating it to regular expressions. This turns out to be a
> lot more subtle than it looks (character classes like [!]-}] tend to
> break things).
>
> In doing this, I wrote a matchCharClass function for handling
> character classes. The initial version had type:
>
> matchCharClass :: Pattern -> Char -> (Bool, Pattern)
>
> I.e. - it returned rest of pattern after the char class as well as a
> match succeed/fail indicator. Upon reflection, I realized that only
> one of the two was ever used, so rewrote it to be:
>
> matchCharClass :: Pattern -> Char -> Either Bool Pattern
>
> This made the calling code a little larger - taking a apart tuples is
> a bit easier than taking apart Either's - but simplified the values
> being generated. I then realized that the code only used one of the
> Bool values: if it was True, then Pattern got used instead. So I
> rewrote it a third time, giving:
>
> data CharClass = Fail | Pattern String
> matchCharClass :: Pattern -> Char -> CharClass
>
> This only required minor changes to the code, but made it easy to add
> "Error String" to the CharClass datatype later. That version can be
> seen at http://pastebin.com/eyre8795 (as always, critiques welcome).
>
> I'd like to hear what more experienced haskell programmers have to say
> about those three ways of returning multiple values.
>
> Thanks,
> <mike
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