cds-amal

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Explain the solidity memory anotation

The memory keyword in Solidity is used to denote a temporary storage location within the Ethereum Virtual Machine (EVM) for variables that are not meant to persist between function calls. This is analogous to RAM in a computer, where data stored in memory is temporary and gets erased after the execution of the function it is used in. The EVM has three primary storage locations for data: storage, memory, and stack.

• Storage: This is where all the contract's state variables reside. It is persistent across function calls and is more expensive to use due to the cost of writing to the blockchain.
• Memory: This is used for temporary data. It is cheaper to use than storage because it is erased between function calls, making it suitable for intermediate calculations or temporary data structures.
• Stack: This is used for small local variables and is almost free to use, but it has a limited capacity.

When you declare a variable with the memory keyword,

cds-amal

// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.21;

contract Empty {
    // hi, I'm bar. i was audited
    function foo() public {}          
    function bar() public {}          
}

/*

cds-amal

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object "YulString" {
    code {
        // Deploy the contract
        datacopy(0, dataoffset("runtime"), datasize("runtime"))
        return(0, datasize("runtime"))        
    }

    object "runtime" {
        code {
            // don't accept value

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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract A {
    function foo() public         pure returns (uint) { return bar(); }
    function bar() public virtual pure returns (uint) { return 1; }
}

contract B is A { }

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// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,

cds-amal

I set up test project based on the metacoin-box (truffle unbox metacoin mc) with two test folders

• test - has js tests
• test-solidity - has solidity tests

Test layout

╭─amal@falafel  ~/.scratch/2022/07/18/swiss-dirs/mc ‹node-16.16.0›  ‹›

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reprod test-from truffle unbox metacoin rm contracts/Migrations.sol rm migrations/*.js cat << EOF > migrations/1_deploy_it.js const ConvertLib = artifacts.require("ConvertLib"); const MetaCoin = artifacts.require("MetaCoin");

module.exports = async function(deployer, network, accounts) { const from = accounts[1];

cds-amal

verdaccio

1. install

   npm -g install verdaccio

2. configure

   cat << EOF > config.yml
   listen: