aivi.core.range

Integer range utilities with an inclusive [start, end] interval type. All operations are pure AIVI — no I/O, no intrinsics.

use aivi.core.range (
    RangeInt
    make
    isEmpty
    contains
    length
    overlaps
    clampTo
    startOf
    endOf
    shift
    intersect
)

---

Type

RangeInt

type RangeInt = {
    start: Int,
    end: Int
}

An inclusive integer range. A range where start > end is considered empty.

---

Construction

make : Int -> Int -> RangeInt

Create a range from start to end (inclusive).

use aivi.core.range (make)

value r = make 1 10

---

Querying

isEmpty : RangeInt -> Bool

Returns True when start > end.

use aivi.core.range (
    isEmpty
    make
)

value none : Bool = isEmpty (make 3 1)

contains : RangeInt -> Int -> Bool

Returns True when n is within the range (inclusive on both ends).

use aivi.core.range (
    contains
    make
)

value hasFive : Bool = contains (make 1 10) 5

length : RangeInt -> Int

Returns the number of integers in the range. Empty ranges have length 0.

use aivi.core.range (
    length
    make
)

value count : Int = length (make 4 7)

startOf : RangeInt -> Int / endOf : RangeInt -> Int

Extract the start or end bound.

use aivi.core.range (
    startOf
    endOf
    make
)

value start : Int = startOf (make 4 7)
value finish : Int = endOf (make 4 7)

---

Operations

clampTo : RangeInt -> Int -> Int

Clamp a value to the range boundaries.

use aivi.core.range (
    clampTo
    make
)

value clamped : Int = clampTo (make 1 10) 15

shift : Int -> RangeInt -> RangeInt

Translate the entire range by a delta.

use aivi.core.range (
    RangeInt
    shift
    make
)

value shifted : RangeInt = shift 3 (make 1 5)

overlaps : RangeInt -> RangeInt -> Bool

Returns True when two ranges share at least one integer. Empty ranges never overlap.

use aivi.core.range (
    make
    overlaps
)

value sharesValues : Bool = overlaps (make 1 5) (make 4 8)

intersect : RangeInt -> RangeInt -> RangeInt

Returns the intersection of two ranges. If the ranges do not overlap the result is an empty range (start > end).

use aivi.core.range (
    RangeInt
    intersect
    make
)

value shared : RangeInt = intersect (make 1 5) (make 4 8)

---

Real-world example

use aivi.core.range (
    RangeInt
    clampTo
    length
)

type Viewport = {
    visible: RangeInt,
    total: Int
}

type Viewport -> RangeInt
func visibleRange = viewport => viewport
 ||> { visible, total } -> visible

type Viewport -> Int
func visibleCount = viewport =>
    length (visibleRange viewport)

type Viewport -> Int -> Int
func clampSelection = viewport row =>
    clampTo (visibleRange viewport) row