https://github.com/eeue56/elm-lazy

https://github.com/eeue56/elm-lazy

Last synced: about 2 months ago
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• Host: GitHub
• URL: https://github.com/eeue56/elm-lazy
• Owner: eeue56
• License: bsd-3-clause
• Created: 2017-06-30T22:37:58.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2018-05-26T16:40:09.000Z (over 6 years ago)
• Last Synced: 2024-10-30T01:38:15.752Z (3 months ago)
• Language: Elm
• Size: 7.81 KB
• Stars: 10
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# elm-lazy

This library provides a way of putting of computations until they are needed, allowing for expensive calculations later.

    lazySum : Lazy Int

    lazySum =

        lazy (\() -> sum <| List.range 1 1000000)

It also gives you a way of storing a computed value so that you do not need to re-compute it.

    lazySum : Int -> Lazy Int

    lazySum n =

        lazy (\() -> sum <| List.range 0 n)

    lazySums : List Int -> List (Lazy Int)

    lazySums sums =

        List.map lazySum sums

    -- evaluates the head, before putting it back on the list

    evaluteCurrentSum : List (Lazy Int) -> List (Lazy Int)

    evaluteCurrentSum xs =

       case xs of 

         head::rest -> Lazy.evaluate head :: rest

         _ -> []

## Notes

This is a library based originally on the old `Lazy` implementation. However, it is written entirely in pure Elm. The main difference is explicit memoization, as we no longer use side-effects to achieve laziness.