[Haskell-cafe] Purely Functional Data Structures

G?uenther Schmidt redcom at fedoms.com
Sat Mar 7 18:13:14 EST 2009

Hi Don,

damn, that was quick!

And thx, I'll look into that. The reading it in wasn't much of a 
problem, I had been able to use MS-ODBC for that, there's a driver for 
ODBC files. The problem is more the type of data structure I'd be 
reading it into. In SQL I would have the data indexed by several 
different columns, if I use maps I'd only have one key, so if I need to 
lookup data in the map by a value that is not the key the lookups will 
become quite expensive.

Any suggestions, what do you do in these cases?


Don Stewart schrieb:
> gue.schmidt:
>> Hi,
>> is the above mentioned book still *the* authority on the subject?
>> I bought the book, read about 10 pages and then put it back on the  
>> shelf. Um.
>> In my app I have to deal with 4 csv files, each between 5 - 10 mb, and  
>> some static data.
>> I had put all that data into an Sqlite3 database and used SQL on it.  
>> But, as the requirements keep changing the SQL becomes a bit messy. I  
>> guess we've all had that experience.
>> So I'm wondering if I will find clues in this book how to do my querying  
>> and handling of moderately large data in a more haskellish way and be  
>> able to drop the SQL.
> Use the fine libraries on http://hackage.haskell.org. 
> E.g. bytestring-csv then load that into a finite map?
> These days it is rare to have to roll your own new data structures...
> -- don

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