ianmackenzie/elm-interval/1.0.0

This package implements a simple Interval type for Elm. Various functionality is included for constructing intervals (including as the hull or intersection of other intervals), checking for overlap/intersection/containment, and performing limited arithmetic on intervals:

unitInterval =
    Interval.from 0 1

Interval.endpoints unitInterval
--> ( 0, 1 )

Interval.containingValues [ 2, 1, 3 ]
--> Just (Interval.from 1 3)

Interval.hull
    (Interval.from 1 2)
    (Interval.from 3 5)
--> Interval.from 1 5

Interval.intersection
    (Interval.from 1 3)
    (Interval.from 2 5)
--> Just (Interval.from 2 3)

Interval.intersection
    (Interval.from 1 2)
    (Interval.from 3 5)
--> Nothing

Interval.contains 0 (Interval.from -1 3)
--> True

Interval.contains 5 (Interval.from -1 3)
--> False

Interval.sin (Interval.from 0 pi)
--> Interval.from 0 1

Currently the only functions that have been implemented are ones that were needed by the elm-geometry package, but I'm happy to consider pull requests for other generally-useful functionality. Please open a new issue before starting work, though, so we can discuss different approaches!