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Today's Topics:
1. Re: minimal Haskell concepts subset (David F. Place)
2. Re: code critique (Gary Klindt)
3. [Code Review] csv file to sqlite3 (Shakthi Kannan)
4. Re: [Code Review] csv file to sqlite3 (aditya siram)
5. Re: [Code Review] csv file to sqlite3 (Shakthi Kannan)
----------------------------------------------------------------------
Message: 1
Date: Wed, 27 Jul 2011 16:01:18 +0000 (UTC)
From: David F. Place <d...@vidplace.com>
Subject: Re: [Haskell-beginners] minimal Haskell concepts subset
To: beginners@haskell.org
Message-ID: <loom.20110727t175455-...@post.gmane.org>
Content-Type: text/plain; charset=us-ascii
Davi Santos <dps.abc <at> gmail.com> writes:
>
> If somebody knows another minihaskell, please let me know.
>
> Davi
>
For me, the most important ideas about Haskell are contained in the
Untyped Lambda Calculus and the Simply-Typed Lambda Calculus.
Yes, it's math, but a little goes a long way.
http://en.wikipedia.org/wiki/Lambda_calculus
------------------------------
Message: 2
Date: Thu, 28 Jul 2011 00:59:50 +0200
From: Gary Klindt <gary.kli...@uni-konstanz.de>
Subject: Re: [Haskell-beginners] code critique
To: aditya siram <aditya.si...@gmail.com>
Cc: beginners@haskell.org
Message-ID: <4e309866.9020...@uni-konstanz.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I repeated the profiling:
print $ sumCheck 500 [1..1000] [1..1000]
sumCheck1: 58,648
sumCheck2: 58,484
sumCheck3: 70,016
print $ sumCheck 5000 [1..10000] [1..10000]
sumCheck1: 238,668
sumCheck2: 238,504
sumCheck3: 358,016
(unit: byte)
This time I used the same compiler flags as Aditya (all but -rtsopts, I
got:ghc: unrecognised flags: -rtsopts ). I'm using GHC version 6.12.1.
Ok, in this numerical example, the scaling of sumCheck3 is not worse
than the other's. In my first run I used quasi random numbers (fingers
on my keyboard). Maybe you got puzzled with your '.prof' files? They
seem identical (there always exists a function sum)
On 07/27/2011 07:34 AM, aditya siram wrote:
> I just profiled all three and have not found them to be different.
> Maybe I'm reading my profiler output wrong so I've pasted it below.
> The compilation command I used was:
> ghc -fforce-recomp -XBangPatterns -prof -rtsopts -auto-all -o
> ListCrossProductSum ListCrossProductSum.hs
>
> They were all invoked using:
> main = print $ sumCheck 5000 [1..10000] [1..10000]
>
> I am running GHC 7.0.1
>
> -deech
>
> sumcheck1:
> ==========
> Wed Jul 27 00:26 2011 Time and Allocation Profiling Report (Final)
>
> ListCrossProductSum +RTS -p -RTS
>
> total time = 0.00 secs (0 ticks @ 20 ms)
> total alloc = 344,084 bytes (excludes profiling overheads)
>
> COST CENTRE MODULE %time %alloc
>
> sums Main 0.0 40.7
> main Main 0.0 58.3
>
>
>
> individual inherited
> COST CENTRE MODULE
> no. entries %time %alloc %time %alloc
>
> MAIN MAIN
> 1 0 0.0 0.0 0.0 100.0
> CAF Main
> 240 2 0.0 0.2 0.0 99.2
> main Main
> 246 1 0.0 58.3 0.0 99.0
> sumCheck Main
> 247 1 0.0 0.0 0.0 40.7
> sums Main
> 248 1 0.0 40.7 0.0 40.7
> CAF GHC.Show
> 236 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.FD
> 176 2 0.0 0.4 0.0 0.4
> CAF System.Posix.Internals
> 175 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.Internals
> 140 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Encoding.Iconv
> 134 2 0.0 0.3 0.0 0.3
> CAF GHC.Conc.Signal
> 131 1 0.0 0.1 0.0 0.1
>
> sumcheck2
> =========
> [1 of 1] Compiling Main ( ListCrossProductSum.hs,
> ListCrossProductSum.o )
> True
> Wed Jul 27 00:27 2011 Time and Allocation Profiling Report (Final)
>
> ListCrossProductSum +RTS -p -RTS
>
> total time = 0.00 secs (0 ticks @ 20 ms)
> total alloc = 344,084 bytes (excludes profiling overheads)
>
> COST CENTRE MODULE %time %alloc
>
> sums Main 0.0 40.7
> main Main 0.0 58.3
>
>
>
> individual inherited
> COST CENTRE MODULE
> no. entries %time %alloc %time %alloc
>
> MAIN MAIN
> 1 0 0.0 0.0 0.0 100.0
> CAF Main
> 240 2 0.0 0.2 0.0 99.2
> main Main
> 246 1 0.0 58.3 0.0 99.0
> sumCheck Main
> 247 1 0.0 0.0 0.0 40.7
> sums Main
> 248 1 0.0 40.7 0.0 40.7
> CAF GHC.Show
> 236 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.FD
> 176 2 0.0 0.4 0.0 0.4
> CAF System.Posix.Internals
> 175 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.Internals
> 140 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Encoding.Iconv
> 134 2 0.0 0.3 0.0 0.3
> CAF GHC.Conc.Signal
> 131 1 0.0 0.1 0.0 0.1
>
> sumcheck3
> =========
> ListCrossProductSum +RTS -p -RTS
>
> total time = 0.00 secs (0 ticks @ 20 ms)
> total alloc = 344,084 bytes (excludes profiling overheads)
>
> COST CENTRE MODULE %time %alloc
>
> sums Main 0.0 40.7
> main Main 0.0 58.3
>
>
>
> individual inherited
> COST CENTRE MODULE
> no. entries %time %alloc %time %alloc
>
> MAIN MAIN
> 1 0 0.0 0.0 0.0 100.0
> CAF Main
> 240 2 0.0 0.2 0.0 99.2
> main Main
> 246 1 0.0 58.3 0.0 99.0
> sumCheck Main
> 247 1 0.0 0.0 0.0 40.7
> sums Main
> 248 1 0.0 40.7 0.0 40.7
> CAF GHC.Show
> 236 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.FD
> 176 2 0.0 0.4 0.0 0.4
> CAF System.Posix.Internals
> 175 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Handle.Internals
> 140 1 0.0 0.0 0.0 0.0
> CAF GHC.IO.Encoding.Iconv
> 134 2 0.0 0.3 0.0 0.3
> CAF GHC.Conc.Signal
> 131 1 0.0 0.1 0.0 0.1
------------------------------
Message: 3
Date: Thu, 28 Jul 2011 07:42:11 +0530
From: Shakthi Kannan <shakthim...@gmail.com>
Subject: [Haskell-beginners] [Code Review] csv file to sqlite3
To: beginners@haskell.org
Message-ID:
<CABG-yt1wb0P729Wh1H1M9Z1m_VKj1+Bdv+JXVvzL=2qknfb...@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Hi,
I am trying to write a simple Haskell program to read from a .csv file
and write to a .sqlite3 database. Can anyone please review the
following code?
=== BEGIN ===
import Text.ParserCombinators.Parsec
import Database.HDBC
import Database.HDBC.Sqlite3
import Control.Monad(when)
-- | Initialize DB and return database Connection
connect :: FilePath -> IO Connection
connect fp =
do dbh <- connectSqlite3 fp
prepDB dbh
return dbh
prepDB :: IConnection conn => conn -> IO ()
prepDB dbh =
do tables <- getTables dbh
when (not ("entries" `elem` tables)) $
do run dbh "CREATE TABLE entries ( \
\id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, \
\first TEXT, \
\second TEXT, \
\third TEXT)" []
return ()
commit dbh
csvFile = endBy line eol
line = sepBy cell (char ';')
cell = quotedCell <|> many (noneOf ";\n\r")
quotedCell =
do char '"'
content <- many quotedChar
char '"' <?> "quote at end of cell"
return content
quotedChar =
noneOf "\""
<|> try (string "\"\"" >> return '"')
eol = try (string "\n\r")
<|> try (string "\r\n")
<|> string "\n"
<|> string "\r"
<?> "end of line"
process :: [String] -> IO ()
process r = do
conn <- connectSqlite3 "simple1.db"
run conn "INSERT INTO entries (first, second, third) VALUES
(?, ?, ?)" (map toSql r)
commit conn
disconnect conn
main = do
dbh <- connect "simple1.db"
do c <- getContents
case parse csvFile "(stdin)" c of
Left e -> do putStrLn "Error parsing input:"
print e
Right r -> do
mapM_ process r
=== END ===
Appreciate any suggestions, improvements in this regard.
Thanks!
SK
--
Shakthi Kannan
http://www.shakthimaan.com
------------------------------
Message: 4
Date: Wed, 27 Jul 2011 21:19:09 -0500
From: aditya siram <aditya.si...@gmail.com>
Subject: Re: [Haskell-beginners] [Code Review] csv file to sqlite3
To: Shakthi Kannan <shakthim...@gmail.com>
Cc: beginners@haskell.org
Message-ID:
<CAJrReyjOSBW6exjKuJesEpW+095_rOc=qo5yv_uremu9r3d...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Hi Shakthi,
Are you aware that there is a csv parsing package on Hackage? If
you're writing the parser as a exercise, Real World Haskell [1] has a
chapter on Parsec that covers csv parsing.
-deech
[1] http://book.realworldhaskell.org/read/using-parsec.html
On Wed, Jul 27, 2011 at 9:12 PM, Shakthi Kannan <shakthim...@gmail.com> wrote:
> Hi,
>
> I am trying to write a simple Haskell program to read from a .csv file
> and write to a .sqlite3 database. Can anyone please review the
> following code?
>
> === BEGIN ===
>
> import Text.ParserCombinators.Parsec
>
> import Database.HDBC
> import Database.HDBC.Sqlite3
> import Control.Monad(when)
>
> -- | Initialize DB and return database Connection
> connect :: FilePath -> IO Connection
> connect fp =
> ? ?do dbh <- connectSqlite3 fp
> ? ? ? prepDB dbh
> ? ? ? return dbh
>
> prepDB :: IConnection conn => conn -> IO ()
> prepDB dbh =
> ? ? ? do tables <- getTables dbh
> ? ? ? ? ?when (not ("entries" `elem` tables)) $
> ? ? ? ? ? ? ? do run dbh "CREATE TABLE entries ( \
> ? ? ? ? ? ? ? ? ?\id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, \
> ? ? ? ? ? ? ? ? ?\first TEXT, \
> ? ? ? ? ? ? ? ? ?\second TEXT, \
> ? ? ? ? ? ? ? ? ?\third TEXT)" []
> ? ? ? ? ? ? ? ? ?return ()
> ? ? ? ? ?commit dbh
>
> csvFile = endBy line eol
> line = sepBy cell (char ';')
> cell = quotedCell <|> many (noneOf ";\n\r")
>
> quotedCell =
> ? ?do char '"'
> ? ? ? content <- many quotedChar
> ? ? ? char '"' <?> "quote at end of cell"
> ? ? ? return content
>
> quotedChar =
> ? ? ? ? ? noneOf "\""
> ? ?<|> try (string "\"\"" >> return '"')
>
> eol = ? try (string "\n\r")
> ? ?<|> try (string "\r\n")
> ? ?<|> string "\n"
> ? ?<|> string "\r"
> ? ?<?> "end of line"
>
>
> process :: [String] -> IO ()
> process r = do
> ? ? ? ?conn <- connectSqlite3 "simple1.db"
> ? ? ? ?run conn "INSERT INTO entries (first, second, third) VALUES
> (?, ?, ?)" (map toSql r)
> ? ? ? ?commit conn
> ? ? ? ?disconnect conn
>
> main = do
> ? ? dbh <- connect "simple1.db"
> ? ? do c <- getContents
> ? ? ? ?case parse csvFile "(stdin)" c of
> ? ? ? ? ? ? Left e -> do putStrLn "Error parsing input:"
> ? ? ? ? ? ? ? ? ? ? ? ? ?print e
> ? ? ? ? ? ? Right r -> do
> ? ? ? ? ? ? ? ? ? mapM_ process r
>
> === END ===
>
> Appreciate any suggestions, improvements in this regard.
>
> Thanks!
>
> SK
>
> --
> Shakthi Kannan
> http://www.shakthimaan.com
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://www.haskell.org/mailman/listinfo/beginners
>
------------------------------
Message: 5
Date: Thu, 28 Jul 2011 07:57:04 +0530
From: Shakthi Kannan <shakthim...@gmail.com>
Subject: Re: [Haskell-beginners] [Code Review] csv file to sqlite3
To: aditya siram <aditya.si...@gmail.com>
Cc: beginners@haskell.org
Message-ID:
<CABG-yt09YeZqcco4DQsbv=LjjezSyQ4vAOjwE=e+k5mqs9s...@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Hi,
--- On Thu, Jul 28, 2011 at 7:49 AM, aditya siram
<aditya.si...@gmail.com> wrote:
| If
| you're writing the parser as a exercise, Real World Haskell [1] has a
| chapter on Parsec that covers csv parsing.
| -deech
|
| [1] http://book.realworldhaskell.org/read/using-parsec.html
\--
I have used import Text.ParserCombinators.Parsec from RWH in the code.
SK
--
Shakthi Kannan
http://www.shakthimaan.com
------------------------------
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