enum-set-unfold | Amirouche Boubekki | 20 Sep 2020 18:34 UTC |

Re: enum-set-unfold | John Cowan | 20 Sep 2020 18:55 UTC |

Re: enum-set-unfold | Wolfgang Corcoran-Mathe | 20 Sep 2020 19:09 UTC |

Re: enum-set-unfold | John Cowan | 20 Sep 2020 21:55 UTC |

Re: enum-set-unfold | Wolfgang Corcoran-Mathe | 20 Sep 2020 23:50 UTC |

Re: enum-set-unfold

*Wolfgang Corcoran-Mathe*20 Sep 2020 23:50 UTCOn 2020-09-20 17:55 -0400, John Cowan wrote: > > There is a serious bit of awkwardness, > > though, in that these integers can only encode combinations of enums > > with ordinals equal to 2^n for some n. > > I assume the intended interpretation is that iff bit n of the integer > (according to the usual SRFI 151 bit numbering) is 1, then ordinal n is in > the set. In which case, getting the bitwise integer back is a fold. That makes a lot more sense to me. I'm still not sure whether these conversions (integer->enum-set and enum-set->integer, probably) seem widely useful. > I > still don't think it makes much sense to use an unfold to populate an > enum-set, though, because the number of possible elements in an enum-set is > not only finite but usually rather small. I had the same thought, but I'd personally still be inclined to include enum-set-unfold. I'll try to come up with some examples where it would be useful. -- Wolfgang Corcoran-Mathe <xxxxxx@sigwinch.xyz> "It from bit." --John Wheeler