[Haskell-beginners] How to show a predicate

[Lyndon Maydwell]

Depending on how you construct your predicates, you may be able to capture
their composition... And then serialise that.

For example:

If you were doing some sort of range intersection predicate construction ~

    R1 n R2 n R3

Could be represented as a list of those ranges [(l1,r1),(l2,r2),(l3,r3)].
Basically, instead of constructing a predicate function directly, you would
assemble a data-structure representing the essence of the predicate, then
convert that to both a function for evaluation, as well as a string for
serialisation. This would also allow you to perform some "optimisation"
before serialisation which could be fun.

Do you have some examples of what the predicates look like?


 - Lyndon

On Wed, Dec 23, 2015 at 8:55 PM, martin <martin.drautzburg at web.de> wrote:

> Hello all,
>
> in my program, I do stuff with predicates (a->Bool). For the most part
> this representation is just fine, but at the very
> end I need to convert a resulting predicate into a String so I can write
> it to a file.
>
> Wenn I represent my predicates as Lists or Sets, then this is doable and I
> am tempted to do it this way. The only other
> option I could come up with was to have a representation of "everything",
> which would in my case be large (10^8) but
> finite. Then I could construct a List or a Set at the very end, as [x |
> x<-everything, p x] without having explicit sets
> in the intermediate steps.
>
> I cannot see any other option, but I thought I better ask.
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/beginners/attachments/20151225/f4a2a7ae/attachment.html>