Plutus for Beginners: Your First Steps into the World of Cardano Smart Contracts – Because It’s Time to Stop Just Using Them and Start Building Them!
Alright, let’s talk about building your own smart contracts on Cardano using Plutus. No, it’s not about becoming a master magician; it’s about harnessing the power of code to create self-executing agreements that can revolutionize the way we interact on the blockchain. Think of it like learning how to build a custom app for your smartphone, instead of relying on what someone else created. So, let’s dive into the world of Plutus, including a detailed guide with code examples to help you get started, with a touch of humor and a lot of clarity.
What is Plutus, Anyway?
Before we start coding, let’s quickly recap what Plutus actually is. Plutus is Cardano’s smart contract platform, providing the tools and languages needed to build secure and reliable decentralized applications (dApps).
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Functional Programming: Plutus is based on the functional programming language Haskell, which emphasizes the use of pure functions and immutability.
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On-Chain and Off-Chain Code: Plutus allows you to write both on-chain and off-chain code, providing a more comprehensive environment for dApp development.
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Formal Verification: Plutus smart contracts are designed to be formally verifiable, which allows them to be mathematically proven to be secure and correct, reducing the chance of bugs and vulnerabilities.
Setting Up Your Development Environment: Getting Ready to Code
Before we write any code, you’ll need to set up your development environment:
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Install Haskell: Plutus is based on Haskell, so you’ll need to install the Haskell development environment on your computer.
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Install the Plutus Tools: You’ll also need to install the Plutus tools, which are a set of libraries and utilities for developing Plutus smart contracts.
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Set Up a Cardano Node: If you are going to deploy your smart contracts on the actual network, you’ll need a running Cardano node. For testing purposes, you can use a local test node, which is easier to set up and manage.
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Basic Understanding of Haskell: Familiarize yourself with the basics of Haskell syntax and functional programming principles.
Your First Plutus Smart Contract: A Simple Example
Let’s start with a simple example to illustrate the basics of Plutus smart contract development. We’ll create a contract that allows a user to withdraw a pre-defined amount of ADA, only after a specific condition is met:
Step 1: The Haskell Code (Off-Chain)
First, we’ll define the off-chain part of our contract in Haskell:
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
module SimpleContract where
import Cardano.Api.Shelley (PlutusScript (PlutusScriptSerialised),
scriptPlutusScript)
import Codec.Serialise (serialise)
import Data.ByteString.Lazy (toStrict)
import qualified Data.ByteString.Short as SBS
import Ledger (Script)
import qualified Ledger.Typed.Scripts as Scripts
import Plutus.V1.Ledger.Api (Datum(..), Redeemer(..), ScriptContext)
import PlutusTx (compile, unstableMakeIsData)
import PlutusTx.Prelude (Bool(..), (&&), (==), ($), (.), otherwise)
import Prelude (Bool, (==), Integer, Show, String, error, IO, ($), putStrLn)
import qualified Plutus.V1.Ledger.Scripts as PlutusScripts
-- Defining Datum and Redeemer types
data MyDatum = MyDatum Integer
unstableMakeIsData ''MyDatum
data MyRedeemer = MyRedeemer Integer
unstableMakeIsData ''MyRedeemer
-- Defining Plutus code for the on-chain validator
{-# INLINEABLE mkValidator #-}
mkValidator :: MyDatum -> MyRedeemer -> ScriptContext -> Bool
mkValidator (MyDatum val) (MyRedeemer red) _ =
val == red
-- Compiling Plutus code to Plutus Script
validator :: Scripts.TypedValidator MyRedeemer MyDatum
validator = Scripts.mkTypedValidator @MyRedeemer @MyDatum
$$(PlutusTx.compile [|| mkValidator ||])
$$(PlutusTx.compile [|| wrap ||])
where
wrap = Scripts.wrapValidator @MyRedeemer @MyDatum
-- Creating Plutus Script
script :: Script
script = PlutusScripts.unValidatorScript $ Scripts.validatorScript validator
-- Creating Plutus Script serialized form
scriptSerialized :: PlutusScript
scriptSerialized = PlutusScriptSerialised $ SBS.toShort bs where
bs = toStrict $ serialise script
Step 2: Explanation of the Code
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Data Types: We define two data types: MyDatum and MyRedeemer. The Datum will contain a secret value, and the Redeemer will contain the input value being tested.
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mkValidator function: This function defines the core logic of the smart contract. It takes a Datum, a Redeemer, and a ScriptContext, as input and returns True if the value of the Datum matches the value of the Redeemer, otherwise it returns False.
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Compilation: The code then compiles our Haskell code into a Plutus script using Template Haskell.
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Serializing Script: The final step serializes the Plutus script into a usable byte string.
Step 3: Using the Smart Contract (Off-Chain)
Now that you have the code of the smart contract, you can use it on the Cardano network. This would require the following steps:
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Create the Datum: You would need to create an UTXO output that contains the Datum, which is the secret value that will be checked later, on the chain.
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Create the Redeemer: When the transaction is created that attempts to unlock the UTXO output locked by the smart contract, it will need to include a Redeemer, which is the input value to be tested.
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Submit the Transaction: A valid transaction will unlock the UTXO locked by the smart contract, when the condition (datum == redeemer) is met.
Key Tools for Plutus Development
Here are some key tools you’ll need for Plutus development:
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Plutus Playground: An online tool for writing, testing, and simulating smart contracts.
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Cardano Node: A local copy of the Cardano node for deploying and interacting with smart contracts.
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Haskell IDE: An integrated development environment for writing and testing Haskell code.
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Cardano CLI: A command-line interface for interacting with the Cardano network.
The Takeaway
Developing smart contracts with Plutus might seem like a daunting task at first, but with a basic understanding of Haskell and the right tools, it’s entirely achievable. This introductory guide will help you get started with building your own smart contracts on Cardano, and unlocking the world of decentralized applications. It’s not just about reading about it; it’s about diving in and creating something amazing!