Purescript

cross-posted from: https://lemmy.world/post/20776659

A quick, naive AI generated Purescript translation (quickly generated that probably doesn’t work but will help get me started later)

module Main where

import Prelude
import Effect (Effect)
import Effect.Aff (launchAff_)
import Effect.Aff.Timer (setInterval)
import Effect.DOM (window)
import Web.HTML (document)
import Web.HTML.Document (getElementById)
import Web.HTML.Element (Element, toElement)
import Web.HTML.HTMLCanvasElement (getContext2D, getCanvasElementById)
import Web.HTML.Canvas.Image (newImage, getWidth, getHeight, setSrc)
import Web.HTML.Canvas.CanvasRenderingContext2D (CanvasRenderingContext2D, drawImage)
import Web.HTML.Types (CanvasElement, Image)
import Web.DOM.Node.Types (Node)

foreign import requestAnimationFrame :: (Effect Unit -> Effect Unit) -> Effect Unit

-- Loads the image and begins the animation
startAnimation :: Effect Unit
startAnimation = do
  img <- newImage
  setSrc img "example1.jpg"
  canvas <- getCanvasElementById "myCanvas"
  context <- getContext2D canvas

  -- We defer animation start until the image is loaded
  imgOnLoad img (beginAnimation context img)

-- Sets the image `onload` handler, safely deferring canvas drawing until the image is ready
imgOnLoad :: Image -> Effect Unit -> Effect Unit
imgOnLoad img action = do
  foreignOnload img action

foreign import foreignOnload :: Image -> Effect Unit -> Effect Unit

-- Initializes the animation loop
beginAnimation :: CanvasRenderingContext2D -> Image -> Effect Unit
beginAnimation context img = do
  imageWidth <- getWidth img
  imageHeight <- getHeight img
  let row = imageHeight
  requestAnimationFrame (animate context img row imageWidth imageHeight)

-- Animates drawing row by row
animate :: CanvasRenderingContext2D -> Image -> Int -> Int -> Int -> Effect Unit
animate context img row imageWidth imageHeight = do
  drawImage context img 0 row imageWidth 1 0 0 imageWidth row
  let nextRow = if row > 0 then row - 1 else imageHeight
  requestAnimationFrame (animate context img nextRow imageWidth imageHeight)

main :: Effect Unit
main = do
  startAnimation

This video demonstrates a quick way to have something nice running with purescript (react + tailwind css + shadcn/ui components)

Repository: https://github.com/Zelenya/purescript-shadcn-tailwind-copypaste

Check out my course "How to think like a functio programmer": https://impurepics.thi.

#fp #functionalprogramming #purescript

I've seen a bit of chatter recently in the PS community about dependent types. Many of us that have been using PureScript for years love it because of its simplicity and elegance, and there has been resistance in the community to build out the complexity, both syntax-wise and implementation-wise, of a full-blown dependently-typed language à la Idris and Agda.

But another reason that there's not much community momentum behind adding dependent types to PureScript is because PureScript already has dependent types 😁

For whatever reason, I decided at 27:00 Friday that I should make a program that would get audio from videos of a Youtube channel. This article will go over the details on why and how I made this with Purescript (and some FFI).

Teaser for the benefits of strongly typed pure functional programming