francesconi / go-rampart

Determine how intervals relate to each other.

go-rampart

Go port of the Haskell Rampart library by Taylor Fausak.

This package provides types and functions for defining intervals and determining how they relate to each other. This can be useful to determine if an event happened during a certain time frame, or if two time frames overlap (and if so, how exactly they overlap).

Install

go get github.com/francesconi/go-rampart

Examples

Ordered types

Any type that supports the operators < <= >= >.

a := rampart.NewInterval(2, 3)
b := rampart.NewInterval(3, 7)
rel := a.Relate(b)
// rel: RelationMeets

Any other type

NewIntervalFunc accepts any type as long as a comparison function is provided. The comparison function should return values as follows:

cmp(t1, t2) < 0 if t1 < t2
cmp(t1, t2) > 0 if t1 > t2
cmp(t1, t2) == 0 if t1 == t2

time.Time

func compareTimes(t1, t2 time.Time) int {
    return int(t1.Sub(t2))
}

a := rampart.NewIntervalFunc(
    time.Date(2022, time.April, 1, 0, 0, 0, 0, time.UTC),
    time.Date(2022, time.April, 8, 0, 0, 0, 0, time.UTC),
    compareTimes,
)
b := rampart.NewIntervalFunc(
    time.Date(2022, time.April, 6, 0, 0, 0, 0, time.UTC),
    time.Date(2022, time.April, 15, 0, 0, 0, 0, time.UTC),
    compareTimes,
)
rel := a.Relate(b)
// rel: RelationOverlaps