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Today's Topics:
1. "Cyclic" instance of Enum (Patrick LeBoutillier)
2. Re: Installing HDBC (Kathleen Lynch)
3. Re: Installing HDBC (Kathleen Lynch)
4. Re: "Cyclic" instance of Enum (Daniel Fischer)
5. Re: Installing HDBC (Daniel Fischer)
6. Re: Installing HDBC (Kathleen Lynch)
7. Re: Installing HDBC (Daniel Fischer)
8. Re: Installing HDBC (Kathleen Lynch)
9. Re: Installing HDBC (JETkoten)
----------------------------------------------------------------------
Message: 1
Date: Tue, 1 Feb 2011 14:14:05 -0500
From: Patrick LeBoutillier <[email protected]>
Subject: [Haskell-beginners] "Cyclic" instance of Enum
To: beginners <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
Hi,
I've created an instance of Enum that repeats the same elements when
it gets to the end:
module Music.Note.Name where
data Name = C | D | E | F | G | A | B
deriving (Show, Eq)
instance Enum Name where
toEnum 0 = C
toEnum 1 = D
toEnum 2 = E
toEnum 3 = F
toEnum 4 = G
toEnum 5 = A
toEnum 6 = B
toEnum i = toEnum $ i `mod` 7
fromEnum C = 0
fromEnum D = 1
fromEnum E = 2
fromEnum F = 3
fromEnum G = 4
fromEnum A = 5
fromEnum B = 6
enumFromTo x y = map toEnum [a .. b']
where a = fromEnum x
b = fromEnum y
b' = if a <= b then b else b + 7
enumFromThen x1 x2 = error "enumFromThen not supported for Music.Note.Name"
enumFromThenTo x1 x2 y = error "enumFromThenTo not supported for
Music.Note.Name"
Does this violate any implicit rules that an Enum instance should
follow? Is there a better way to do this?
Thanks,
Patrick
--
=====================
Patrick LeBoutillier
Rosem?re, Qu?bec, Canada
------------------------------
Message: 2
Date: Tue, 01 Feb 2011 14:20:22 -0500
From: "Kathleen Lynch" <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Daniel Fischer" <[email protected]>
Cc: [email protected]
Message-ID: <3319FC2BB8D24CCB843A23840D5FEDF2@UserPC>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
I entered the command you gave me: cabal install HDBC-sqlite3
It returned the following error:
Resolving dependencies...
Configuring HDBC-sqlite3-2.3.1.0...
cabal: Missing dependency on a foreign library:
* Missing C library: sqlite3
I then went to the link you provided:
http://hackage.haskell.org/package/HDBC-sqlite3
I extracted the tar file, HDBC-sqlite3-2.3.1.0.tar, and tried to un-tar it
but get the following message:
"Error reading header after processing 0 entries"
I'd appreciate any help...
----- Original Message -----
From: "Daniel Fischer" <[email protected]>
To: "Kathleen Lynch" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, February 01, 2011 1:33 PM
Subject: Re: [Haskell-beginners] Installing HDBC
> On Tuesday 01 February 2011 19:03:32, Kathleen Lynch wrote:
>> ...I got everything installed but am getting the following message:
>>
>> Prelude> :module Database.HDBC.Sqlite3
>> <no location info>:
>> Could not find module `Database.HDBC.Sqlite3':
>> it is not a module in the current program, or in any known
>> package.
>
> It's in http://hackage.haskell.org/package/HDBC-sqlite3
>
> $ cabal install HDBC-sqlite3
>
> (similarly for mysql, postgresql, odbc). I suppose those packages depend
> on
> having the foreign library installed, so they come alone. It's a bit
> annoying (especially if one is not told which packages one needs), but
> having to install multiple databases when one wants to use only one would
> be at least as bad.
>
> Cheers,
> Daniel
------------------------------
Message: 3
Date: Tue, 01 Feb 2011 14:23:45 -0500
From: "Kathleen Lynch" <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Kathleen Lynch" <[email protected]>, "Daniel Fischer"
<[email protected]>
Cc: [email protected]
Message-ID: <BD6FD5714F334B269210AD6AF2CFCC2B@UserPC>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=response
BTW, I'm doing this on a Windows Vista PC...
----- Original Message -----
From: "Kathleen Lynch" <[email protected]>
To: "Daniel Fischer" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, February 01, 2011 2:20 PM
Subject: Re: [Haskell-beginners] Installing HDBC
>I entered the command you gave me: cabal install HDBC-sqlite3
> It returned the following error:
> Resolving dependencies...
> Configuring HDBC-sqlite3-2.3.1.0...
> cabal: Missing dependency on a foreign library:
> * Missing C library: sqlite3
>
> I then went to the link you provided:
> http://hackage.haskell.org/package/HDBC-sqlite3
> I extracted the tar file, HDBC-sqlite3-2.3.1.0.tar, and tried to un-tar it
> but get the following message:
> "Error reading header after processing 0 entries"
>
> I'd appreciate any help...
>
>
> ----- Original Message -----
> From: "Daniel Fischer" <[email protected]>
> To: "Kathleen Lynch" <[email protected]>
> Cc: <[email protected]>
> Sent: Tuesday, February 01, 2011 1:33 PM
> Subject: Re: [Haskell-beginners] Installing HDBC
>
>
>> On Tuesday 01 February 2011 19:03:32, Kathleen Lynch wrote:
>>> ...I got everything installed but am getting the following message:
>>>
>>> Prelude> :module Database.HDBC.Sqlite3
>>> <no location info>:
>>> Could not find module `Database.HDBC.Sqlite3':
>>> it is not a module in the current program, or in any known
>>> package.
>>
>> It's in http://hackage.haskell.org/package/HDBC-sqlite3
>>
>> $ cabal install HDBC-sqlite3
>>
>> (similarly for mysql, postgresql, odbc). I suppose those packages depend
>> on
>> having the foreign library installed, so they come alone. It's a bit
>> annoying (especially if one is not told which packages one needs), but
>> having to install multiple databases when one wants to use only one would
>> be at least as bad.
>>
>> Cheers,
>> Daniel
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
------------------------------
Message: 4
Date: Tue, 1 Feb 2011 20:43:01 +0100
From: Daniel Fischer <[email protected]>
Subject: Re: [Haskell-beginners] "Cyclic" instance of Enum
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
On Tuesday 01 February 2011 20:14:05, Patrick LeBoutillier wrote:
> Hi,
>
> I've created an instance of Enum that repeats the same elements when
> it gets to the end:
>
>
> Does this violate any implicit rules that an Enum instance should
> follow?
If you make that type also an instance of Bounded. Says the report:
> For any type that is an instance of class Bounded as well as Enum, the
> following should hold:
>
> * The calls succ maxBound and pred minBound should result in a
> runtime error. * fromEnum and toEnum should give a runtime error if the
> result value is not representable in the result type. For example,
> toEnum 7 :: Bool is an error. * enumFrom and enumFromThen should be
> defined with an implicit bound, thus: enumFrom x = enumFromTo
> x maxBound
> enumFromThen x y = enumFromThenTo x y bound
> where
> bound | fromEnum y >= fromEnum x = maxBound
>
> | otherwise = minBound
but otherwise, it's okay.
> Is there a better way to do this?
None obvious.
Cheers,
Daniel
------------------------------
Message: 5
Date: Tue, 1 Feb 2011 21:07:01 +0100
From: Daniel Fischer <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Kathleen Lynch" <[email protected]>
Cc: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
On Tuesday 01 February 2011 20:20:22, Kathleen Lynch wrote:
> I entered the command you gave me: cabal install HDBC-sqlite3
> It returned the following error:
> ? ? Resolving dependencies...
> ? ? Configuring HDBC-sqlite3-2.3.1.0...
> ? ? cabal: Missing dependency on a foreign library:
> ? ? * Missing C library: sqlite3
That means you don't have the C library installed, or at least that cabal
can't find it. You have to install it otherwise or put it in a directory in
your %PATH%. I'm not familiar with Windows, so I can't tell you how to do
that. You could search on the haskellwiki, perhaps there are instructions
there.
>
> I then went to the link you provided:
> http://hackage.haskell.org/package/HDBC-sqlite3
> I extracted the tar file, HDBC-sqlite3-2.3.1.0.tar, and tried to un-tar
> it but get the following message:
> ? ? "Error reading header after processing 0 entries"
If cabal complains about a missing foreign dependency, trying a manual
install won't help, runhaskell ./Setup configure won't look anywhere cabal
doesn't.
------------------------------
Message: 6
Date: Tue, 01 Feb 2011 16:39:02 -0500
From: "Kathleen Lynch" <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Daniel Fischer" <[email protected]>
Cc: [email protected]
Message-ID: <05C0348F9D5E41B299D08921839AD1D7@UserPC>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
...almost a rhetorical question - but does Haskell support "Microsoft SQL
Server 2005 Compact Edition"?
----- Original Message -----
From: "Daniel Fischer" <[email protected]>
To: "Kathleen Lynch" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, February 01, 2011 3:07 PM
Subject: Re: [Haskell-beginners] Installing HDBC
On Tuesday 01 February 2011 20:20:22, Kathleen Lynch wrote:
> I entered the command you gave me: cabal install HDBC-sqlite3
> It returned the following error:
> Resolving dependencies...
> Configuring HDBC-sqlite3-2.3.1.0...
> cabal: Missing dependency on a foreign library:
> * Missing C library: sqlite3
That means you don't have the C library installed, or at least that cabal
can't find it. You have to install it otherwise or put it in a directory in
your %PATH%. I'm not familiar with Windows, so I can't tell you how to do
that. You could search on the haskellwiki, perhaps there are instructions
there.
>
> I then went to the link you provided:
> http://hackage.haskell.org/package/HDBC-sqlite3
> I extracted the tar file, HDBC-sqlite3-2.3.1.0.tar, and tried to un-tar
> it but get the following message:
> "Error reading header after processing 0 entries"
If cabal complains about a missing foreign dependency, trying a manual
install won't help, runhaskell ./Setup configure won't look anywhere cabal
doesn't.
------------------------------
Message: 7
Date: Tue, 1 Feb 2011 22:59:27 +0100
From: Daniel Fischer <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Kathleen Lynch" <[email protected]>
Cc: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
On Tuesday 01 February 2011 22:39:02, Kathleen Lynch wrote:
> ...almost a rhetorical question - but does Haskell support "Microsoft
> SQL Server 2005 Compact Edition"?
I doubt anybody wrote a binding yet. I didn't find anything on hackage and
most library writers work on *nixen, so the likelihood isn't large. In
principle, however, I see no reason why it shouldn't be possible to write a
binding.
------------------------------
Message: 8
Date: Tue, 01 Feb 2011 17:00:31 -0500
From: "Kathleen Lynch" <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: "Daniel Fischer" <[email protected]>
Cc: [email protected]
Message-ID: <507B51783C7D429F92954AACCD0C4F13@UserPC>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
...I put it in my PATH [C:\users\user] and put the file Sqlite3 in that
folder [C:\users\user] where I'm running Cabal and extended the Cabal
command as follows - nothing helps...
cabal install
HDBC-sqlite3 --extra-include-dirs=C:\Users\User --extra-lib-dirs=C:\Users\User
...At this point, I'm unable to install Sqlite3 and GTK...
...I know this is 'open source' but it really shouldn't be this hard to do
these installations...
...I'll go back to my Monads and see if I can figure them out and then take
a look at F# - I might have better luck there...
Bye
----- Original Message -----
From: "Daniel Fischer" <[email protected]>
To: "Kathleen Lynch" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, February 01, 2011 3:07 PM
Subject: Re: [Haskell-beginners] Installing HDBC
On Tuesday 01 February 2011 20:20:22, Kathleen Lynch wrote:
> I entered the command you gave me: cabal install HDBC-sqlite3
> It returned the following error:
> Resolving dependencies...
> Configuring HDBC-sqlite3-2.3.1.0...
> cabal: Missing dependency on a foreign library:
> * Missing C library: sqlite3
That means you don't have the C library installed, or at least that cabal
can't find it. You have to install it otherwise or put it in a directory in
your %PATH%. I'm not familiar with Windows, so I can't tell you how to do
that. You could search on the haskellwiki, perhaps there are instructions
there.
>
> I then went to the link you provided:
> http://hackage.haskell.org/package/HDBC-sqlite3
> I extracted the tar file, HDBC-sqlite3-2.3.1.0.tar, and tried to un-tar
> it but get the following message:
> "Error reading header after processing 0 entries"
If cabal complains about a missing foreign dependency, trying a manual
install won't help, runhaskell ./Setup configure won't look anywhere cabal
doesn't.
------------------------------
Message: 9
Date: Tue, 01 Feb 2011 18:09:54 -0500
From: JETkoten <[email protected]>
Subject: Re: [Haskell-beginners] Installing HDBC
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 2/1/11 5:00 PM, Kathleen Lynch wrote:
> ...I put it in my PATH [C:\users\user] and put the file Sqlite3 in
> that folder [C:\users\user] where I'm running Cabal and extended the
> Cabal command as follows - nothing helps...
> cabal install HDBC-sqlite3 --extra-include-dirs=C:\Users\User
> --extra-lib-dirs=C:\Users\User
>
> ...At this point, I'm unable to install Sqlite3 and GTK...
>
> ...I know this is 'open source' but it really shouldn't be this hard
> to do these installations...
>
> ...I'll go back to my Monads and see if I can figure them out and then
> take a look at F# - I might have better luck there...
>
> Bye
Any progress on your Mac efforts? In OS X, once you've installed Xcode
and the (*very important*) Unix Development Support part of it, it's as
easy as:
sudo port install sqlite
...if you've also installed Macports, or "port", which is the
cabal-install of the Mac world.
You just run that command in the Terminal command line app (found in
Applications/Utilities) and it automatically puts the app or lib that
you've requested in your path, because macports adds itself and its /opt
directory to your path when you install it.
You'll probably find it a lot easier to add things and have cabal be
able to find them, and it'll be a bit easier for others to help too,
because OS X is *nix-y.
------------------------------
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End of Beginners Digest, Vol 32, Issue 3
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