@line100/rescript-seq

rescript-seq

A Lazy Sequence implimation. Highly abstracted stream like RxJs but without time.

  Deleted Head                        Infinit Tail

┌───┐   ┌───┐   ┌──┬┐   ┌──┬┐   ┌──┬┐
│   │   │   │   │ a│┼───► b│┼───► c│┼───►  ?
└───┘   └───┘   └──┴┘   └──┴┘   └──┴┘
                  ▲       ▲
                  │       │
                  │       │
          ┌─────┬─┘    ┌──┴──┐
          │ ref │      │ ref │
          └─────┘      └─────┘

Installation

npm install @line100/rescript-seq

Usage

// infinit sequence of numbers
let rec createInfinitSeq = (i) =>
    Seq.cons(i, Seq.Lazy(() => Some(createInfinitSeq(i + 1))))

// take and lazyTake
let seq = createInfinitSeq(0)
let first3 = Seq.take(seq, 3)
seqEqual(~message="take first 3 from infinit list", first3, list{0, 1, 2})

let first3 = Seq.lazyTake(seq, 3)
seqEqual(~message="lazyTake first 3 from infinit list", first3, list{0, 1, 2})


// map and lazyMap
let first3 = seq->Seq.take(3)->Seq.map(v => v + 1)
seqEqual(~message="map v + 1 after take first 3 from infinit list", first3, list{1, 2, 3})

let first3 = seq->Seq.lazyMap(v => v + 1)->Seq.take(3)
seqEqual(~message="lazyMap v + 1 before take first 3 from infinit list", first3, list{1, 2, 3})

API

Creation Operators

• [x] fromList: (list<'a>) => t<'a>
• [x] fromArray: (Array<'a>) => t<'a>
• [x] fromArrayInPlace: (Array<'a>) => t<'a>
• [x] fromString: (string) => t<string>, convert string to sequence of char

Conditional Operator

• [x] isEmpty: (t<'a>) => bool
• [x] equal: (t<'a>, t<'a>) => bool
• [x] match: (t<'a>, list<'a>) => bool
• [x] every: (t<'a>, 'a => bool) = bool

Transformation Operator

• [x] map: (t<'a>, 'a => 'b) => t<'b>

• [x] append: (t<'a>, t<'a>) => t<'a>

• [x] lazyMap: (t<'a>, 'a => 'b) => t<'b>

filtering operators

• [x] take: (t<'a>, int) => t<'a>

• [x] takeWhile: (t<'a>, 'a => bool) => t<'a>

• [x] drop: (t<'a>, int) => t<'a>

• [x] dropWhile: (t<'a>, 'a => bool) => t<'a>

• [x] lazyTake: (t<'a>, int) => t<'a>

• [x] lazyTakeWhile: (t<'a>, 'a => bool) => t<'a>