A lightweight F# library for efficient functional-style pipelines on streams of data. The main design behind Streams is inspired by Java 8 Streams and is based on the observation that functional pipelines follow the pattern
source/generator |> lazy |> lazy |> lazy |> eager/reduce- Source/generator are functions that create Streams like Stream.ofArray/Stream.init.
- Lazy functions take in streams and return streams like Stream.map/Stream.filter, these operations are fused together for efficient iteration.
- Eager/reduce are functions like Stream.iter/Stream.sum that force the Stream to evaluate up to that point.
For simple pipelines we have observed performance improvements of a factor of four and for more complex pipelines the performance gains are even greater.
open Nessos.Streams.Core
let data = [|1..10000000|] |> Array.map int64
// Real: 00:00:00.044, CPU: 00:00:00.046, GC gen0: 0, gen1: 0, gen2: 0
data
|> Stream.ofArray
|> Stream.filter (fun x -> x % 2L = 0L)
|> Stream.map (fun x -> x + 1L)
|> Stream.sum
// Real: 00:00:00.264, CPU: 00:00:00.265, GC gen0: 0, gen1: 0, gen2: 0
data
|> Seq.filter (fun x -> x % 2L = 0L)
|> Seq.map (fun x -> x + 1L)
|> Seq.sum
// Real: 00:00:00.217, CPU: 00:00:00.202, GC gen0: 0, gen1: 0, gen2: 0
data
|> Array.filter (fun x -> x % 2L = 0L)
|> Array.map (fun x -> x + 1L)
|> Array.sumInstall-Package Streams