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{-# Language TypeSynonymInstances, FlexibleInstances #-}

module Algj where

import Debug.Trace
import Data.Maybe
import qualified Data.Map as M
import qualified Data.Set as S
import Control.Monad.Trans.State

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{-# Language TypeSynonymInstances, FlexibleInstances #-}

module Algw where

import Data.Maybe
import qualified Data.Map as M
import qualified Data.Set as S
import Control.Monad.Trans.State

yelouafi

Network Requests

There are a few ways to get info from an API

---

What is await?

const response = await fetch("mysite.com/api/dogs")

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Algebraic Effects in JavaScript part 4 - Implementing Algebraic Effects and Handlers

This is the final part of a series about Algebraic Effects and Handlers.

• Part 1 : continuations and control transfer
• Part 2 : Capturing continuations with Generators
• Part 3 : Delimited continuations
• Part 4 : Implementing Algebraic Effects and handlers

So we've come to the core topic. The reality is that we've already covered most of it in the previous parts. Especially, in the third part, where we saw delimited continuations at work.

yelouafi

Algebraic Effects in JavaScript part 3 - Delimited Continuations

This is the third part of a series about Algebraic Effects and Handlers.

• Part 1 : continuations and control transfer
• Part 2 : Capturing continuations with Generators
• Part 3 : Delimited continuations
• Part 4 : Algebraic Effects and handlers

In the preceding parts, we introduced the notions of continuations and control transfer. We saw how to capture the current

yelouafi

Algebraic Effects in JavaScript part 2 - Capturing continuations with Generators

This is the second part of a series about Algebraic Effects and Handlers.

• Part 1 : continuations and control transfer
• Part 2 : Capturing continuations with Generators
• Part 3 : Delimited continuations
• Part 4 : Algebraic Effects and handlers

Note: initially I planned a 3-part series, but since the current post on undelimited continuations ended up taking

yelouafi

function isGenerator(x) {
  return x != null && typeof x.next === "function"
}

function isFrame(x) {
  return x != null && x._type_ === 'call_frame'
}

function call(genFunc, ...args) {

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Algebraic Effects in JavaScript part 1 - continuations and control transfer

This is the first post of a series about Algebraic Effects and Handlers.

There are 2 ways to approach this topic:

• Denotational: explain Algebraic Effects in terms of their meaning in mathematics/Category theory
• Operational: explain the mechanic of Algebraic Effects by showing how they operate under a chosen runtime environment

Both approaches are valuables and give different insights on the topic. However, not everyone (including me), has the prerequisites to grasp the concepts of Category theory and Abstract Algebra. On the other hand, the operational approach is accessible to a much wider audience of programmers even if it doesn't provide the full picture.

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// We model the call stack using a linked list of Generators
// Each Generator has a _return field pointing back to its parent

function stepGen(gen, arg) {
    const {done, value} = gen.next(arg)
    if(done) {        
        if(gen._return) {
            stepGen(gen._return, value)
        }

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function*example() {
    const x = 10
    const y = yield callcc(function*(k) {
        // ...
        yield k(20)
        throw "Unreachable code"
    })
    console.log(x + y)
}