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async/await is just the do-notation of the Promise monad

CertSimple just wrote a blog post arguing ES2017's async/await was the best thing to happen with JavaScript. I wholeheartedly agree.

In short, one of the (few?) good things about JavaScript used to be how well it handled asynchronous requests. This was mostly thanks to its Scheme-inherited implementation of functions and closures. That, though, was also one of its worst faults, because it led to the "callback hell", an seemingly unavoidable pattern that made highly asynchronous JS code almost unreadable. Many solutions attempted to solve that, but most failed. Promises almost did it, but failed too. Finally, async/await is here and, combined with Promises, it solves the problem for good. On this post, I'll explain why that is the case and trace a link between promises, async/await, the do-notation and monads.

First, let's illustrate the 3 styles by implementing

bneiluj

//import "openzeppelin-solidity/contracts/ECRecovery.sol";

contract InviteLink {
    using ECRecovery for bytes32;
    IERC1077 owner;
    
    // Mappings of transit pub key => true if link is used.
    mapping (bytes => bool) usedLinks;

    constructor(IERC1077 _owner) {

bneiluj

echo "Enter your key password:" 
read -s password

while true
do
  amount_steak=$(gaiacli query account <comosaddr> --chain-id=9002 --trust-node=true | jq -r '.value.coins[0].amount')
	if [[ $amount_steak > 0 && $amount_steak != "null" ]]; then
	        echo "About to stake ${amount_steak} steak"
	        echo "${password}" | gaiacli tx delegate --amount=${amount_steak}steak --from=crytter --validator=<cosmosvaloper> --chain-id=gaia-9001
	fi

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echo "Enter your key password:" 
read -s password

while true
do
  amount_steak=$(gaiacli query account <comosaddr> --chain-id=9002 --trust-node=true | jq -r '.value.coins[0].amount')
	if [[ $amount_steak > 0 && $amount_steak != "null" ]]; then
	        echo "About to stake ${amount_steak} steak"
	        echo "${password}" | gaiacli tx delegate --amount=${amount_steak}steak --from=crytter --validator=<cosmosvaloper> --chain-id=gaia-9002
	fi

bneiluj

#!/bin/bash

# Upgrade the system and install go
sudo apt update
sudo apt upgrade -y
sudo apt install gcc git make -y
sudo snap install --classic go
sudo mkdir -p /opt/go/bin

# Export environment variables

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[
  {
    "user": "0xDA6B746B76fDC8424764d6981e9eF5C3b13A56af",
    "transactionHash": "0x7d9e3f20d67637fcf7423bae7d1659707978b79f09c67978db0dcde2239040fa",
    "amount": 14752.704765297914,
    "blockNumber": 11694521,
    "dexes": [
      {
        "uniswap": 14752.704765297914
      }

bneiluj

"Txhash","Blockno","UnixTimestamp","DateTime","From","To","Quantity" "0xc9851f374701f76024c1f44f7166e0ef8a99456750463dc9d7b426e6359b9b20","12168368","1617476386","2021-04-03 18:59:46","0x0000000000000000000000000000000000000000","0xbffb152b9392e38cddc275d818a3db7fe364596b","1302613195.32604" "0xc9851f374701f76024c1f44f7166e0ef8a99456750463dc9d7b426e6359b9b20","12168368","1617476386","2021-04-03 18:59:46","0x0000000000000000000000000000000000000000","0x9b0c6299d08fe823f2c0598d97a1141507e4ad86","1315770904.36974" "0xc9851f374701f76024c1f44f7166e0ef8a99456750463dc9d7b426e6359b9b20","12168368","1617476386","2021-04-03 18:59:46","0x9b0c6299d08fe823f2c0598d97a1141507e4ad86","0x94b0a3d511b6ecdb17ebf877278ab030acb0a878","1315770904.36974" "0xc9851f374701f76024c1f44f7166e0ef8a99456750463dc9d7b426e6359b9b20","12168368","1617476386","2021-04-03 18:59:46","0x9b0c6299d08fe823f2c0598d97a1141507e4ad86","0x0000000000000000000000000000000000000000","0" "0xc9851f374701f76024c1f44f7166e0ef8a99456750463dc9d7b426e6359b9b20","1216