[Haskell-beginners] Ranges and List Comprehensions in SQL
byorgey at seas.upenn.edu
Thu Sep 2 17:52:32 EDT 2010
On Thu, Sep 02, 2010 at 03:54:12PM -0400, Tom Murphy wrote:
> Hi Everyone,
> Is there a "From SQL"-type function that "restores" a range or list
> Let's say I want to keep track of which episodes of a TV show I've seen. I
> have an SQL table, in which is a record:
> id (INTEGER): 30
> title (VARCHAR): "The Simpsons"
> episodes_watched (Some data format): [1..4], , [18..21], [23..25]
> Then, when I pull the record, in Haskell, the "Episodes Watched" is already
> one list:
> , or a series of lists that I can append together:
> [1,2,3,4], , [18,19,20,21], [23,24,25]
> Note in the example that I would like to be able to store multiple ranges
> within a single record.
I am not sure I understand what you are asking. Do you want something
data Range = Range Integer Integer
toRanges :: [Integer] -> [Range]
toRanges = ...
toRanges should not be too hard to write but nothing like that exists
as far as I know.
But I'm pretty sure I haven't understood your question, because I
don't see what SQL has to do with it. Are you actually using a
database? Or are you just using SQL as inspiration?
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