[Haskell-cafe] Set of reals...?

Graham Klyne GK at ninebynine.org
Wed Oct 27 04:51:29 EDT 2004

I think the first question you have to address is whether you really want 
to represent a *set* of reals or an *interval* of reals.  Then, some other 
questions follow:
- possibly infinite sets within any given interval?
- open or closed intervals?
and probably more.


At 16:56 27/10/04 +0900, Stijn De Saeger wrote:
>Hi all,
>I'm new to this list, as well as to haskell, so this question probably
>has "newbie" written all over it.
>I'm thinking of a way to represent a set of reals, say the reals
>between 0.0 and 1.0.  Right now I am just using a pair of Float to
>represent the lower and upper bounds of the set, but i have this dark
>throbbing feeling that there should be a more haskellish way to do
>this, using laziness.
>List comprehensions are out it seems, because they increment with
>integer steps... (obviously). In other words,  0.5 `inSet` (Set
>[0.0..1.0])   returns False.
>I'm sure someone must have hit this problem before me and found a way
>around it.
>any suggestions greatly appreciated,
>Haskell-Cafe mailing list
>Haskell-Cafe at haskell.org

Graham Klyne
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