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unit.json	unit.json

title	author
M06 - Building Smart Contracts	Walker Leite

Introduction

Getting Started

In this module we'll check the Plutus Validator and we'll compile and use our first smart contract in Haskell.

To run this presentation type (you will need nix):

../../slide README.md

Community Support

LovelaceAcademy Discord
StackExchange (:bulb: use the tag lovelace-academy)
Plutonomicon Discord

What you should know

Nix (module 1)
Nix flakes (module 3)
PureScript (modules 2-5)

Nix Overlays

Example

Overlay is a feature of nixpkgs (and some flake packages) to allow you to add/override set attributes:

let pkgs = import <nixpkgs> {
    overlays = [
        (self: super: {
          boost = super.boost.override {
            python = self.python3;
          };
        })
    ];
};
in
    # pkgs.boost with python3
    pkgs.boost;

apply-systems also receive an overlays attribute that apply overlays in the given inputs:

{
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
  inputs.utils.url = "github:ursi/flake-utils";
  outputs = { self, utils, ... }@inputs:
    utils.apply-systems
      {
        inherit inputs;
        overlays = [
            (self: super: {
              ls = super.sl;
            })
        ];
      }
      ({ pkgs, ... }: {
        # Try `ls` in the `nix develop` shell ;-)
        devShells.default = pkgs.mkShell {
            buildInputs = [ pkgs.ls ];
        };
      });
}

Haskell

Differences between Haskell and PureScript

In Haskell (GHC) we need to use extensions to enable some builtin PureScript features.

Eg: To create custom kinds we need some extensions

-- PureScript
data Token

-- it means Ada type has kind Token
foreign import data Ada :: Token 

data Value :: forall k. k -> Type -> Type
data Value a b = Value b

value1 :: Value Ada Int
value1 = Value 5

{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE StandaloneKindSignatures #-}
module Main where

data Token = Ada

type Value :: forall k. k -> * -> *
data Value a b = MkValue b

value1 :: Value Ada Int
value1 = MkValue 5

There are more differences, but in general the compiler will let you know.

PureScript to Haskell;
Differences from Haskell describes in one page the differences between the languages;
GHC describes in one page Haskell extensions.

Haskell Nix

Why Haskell Nix

Haskell Nix

Bootstrap

mkdir haskell-project
cd haskell-project
git init
nix flake init --template github:LovelaceAcademy/nix-templates#hix
git status

...
        new file:   .gitignore
        new file:   flake.lock
        new file:   flake.nix
        new file:   hello.cabal
        new file:   nix/hix.nix
        new file:   src/hello.hs

Source code and cabal

-- src/hello.hs
module Main (main) where

main = putStrLn "Hello, World!"

-- hello.cabal
-- ...
executable hello
  hs-source-dirs: src
  main-is: hello.hs
-- ...

Nix flake

{
  # ...
  outputs = { self, utils, ... }@inputs:
    utils.apply-systems
      {
        inherit inputs;
        # TODO support additional systems
        #  right now we can't afford to test every other system
        systems = [ "x86_64-linux" "aarch64-linux" ];
        overlays = [ inputs.haskell-nix.overlay ];
      }
      ({ pkgs, system, ... }:
        let
          hixProject = pkgs.haskell-nix.hix.project {
            src = ./.;
            evalSystem = "x86_64-linux";
          };
          flake = hixProject.flake { };
        in
        # Flake definition follows hello.cabal
        flake // {
          legacyPackages = pkgs;
        });
        # ...
}

Hix options

# nix/hix.nix
{pkgs, ...}: {
  # name = "project-name";
  
  # We use the latest supported and cached version
  # from github:input-output-hk/haskell.nix
  compiler-nix-name = "ghc925";

  # Enable for cross-platform build
  # crossPlatforms = p: pkgs.lib.optionals pkgs.stdenv.hostPlatform.isx86_64 ([
  #   p.mingwW64
  #   p.ghcjs
  # ] ++ pkgs.lib.optionals pkgs.stdenv.hostPlatform.isLinux [
  #   p.musl64
  # ]);

  # Tools to include in the development shell
  shell.tools.cabal = "latest";
  # shell.tools.hlint = "latest";
  # shell.tools.haskell-language-server = "latest";
}

Outputs

# show all outputs of the hello project
nix flake show --allow-import-from-derivation

git+file:///path/to/project
├───apps
...
│   └───x86_64-linux
│       └───"hello:exe:hello": app
├───checks
...
│   └───x86_64-linux
├───devShell
...
│   └───x86_64-linux: development environment 'ghc-shell-for-hello'
...
└───packages
...
    └───x86_64-linux
        ├───"hello:exe:hello": package 'hello-exe-hello-1.0.0.2'
...

Build and Run

nix build .#hello:exe:hello
tree result

result
└── bin
    └── hello

./result/bin/hello
nix run .#hello:exe:hello

Hello, World!
Hello, World!

Adding Plutus

Bootstrap

mkdir plutus-project
cd plutus-project
git init
nix flake init --template github:LovelaceAcademy/nix-templates#hix-plutus
git status

...
        new file:   .gitignore
        new file:   cabal.project
        new file:   flake.lock
        new file:   flake.nix
        new file:   hello.cabal
        new file:   nix/hix.nix
        new file:   nix/serve-docs.nix
        new file:   src/hello.hs

flake.nix

{
  # ...
  inputs.iohk-nix.url = "github:input-output-hk/iohk-nix";
  inputs.CHaP.url = "github:input-output-hk/cardano-haskell-packages?ref=repo";
  inputs.CHaP.flake = false;
  # to generate docs
  inputs.plutus.url = "github:input-output-hk/plutus";
  # ...
  outputs = { self, utils, ... }@inputs:
    utils.apply-systems
      {
        # ...
        overlays = [
          inputs.haskell-nix.overlay
          # plutus runtime dependency
          inputs.iohk-nix.overlays.crypto
        ];
      }
      ({ pkgs, system, ... }@context:
        let
          hixProject = pkgs.haskell-nix.hix.project {
            # ...
            inputMap = { "https://input-output-hk.github.io/cardano-haskell-packages" = inputs.CHaP; };
            modules = [
              (_: {
                # See input-output-hk/iohk-nix#488
                packages.cardano-crypto-praos.components.library.pkgconfig =
                  pkgs.lib.mkForce [ [ pkgs.libsodium-vrf ] ];
                packages.cardano-crypto-class.components.library.pkgconfig =
                  pkgs.lib.mkForce [ [ pkgs.libsodium-vrf pkgs.secp256k1 ] ];
              })
            ];
          };
          hixFlake = hixProject.flake { };
          serve-docs = import ./nix/serve-docs.nix inputs context {
            inherit hixProject;
            additionalPkgs = [ "cardano-api" ];
          };
        in
        # ...
}

hello.cabal and cabal.project

-- cabal.project
-- ...
repository cardano-haskell-packages
  url: https://input-output-hk.github.io/cardano-haskell-packages
  secure: True
  root-keys:
    3e0cce471cf09815f930210f7827266fd09045445...
-- ...
packages: ./.

package *
  -- Reduce build times, set True for production
  optimization: False
-- ...

-- hello.cabal
-- ...
executable hello
  import: lang
  hs-source-dirs: src
  main-is: hello.hs
  build-depends:
      base
    , bytestring
    , cardano-api
    , plutus-ledger-api
    , plutus-tx
    , plutus-tx-plugin
    , serialise

hello.hs

-- ...
validator :: BuiltinData -> BuiltinData -> BuiltinData -> ()
validator datum redeemer context = ()

validator' :: Validator
validator' = mkValidatorScript $$(compile [||validator||])

serialise :: Validator -> PlutusScript PlutusScriptV2
serialise val = PlutusScriptSerialised $ DBS.toShort $ DBL.toStrict $ CS.serialise $ val

main :: IO ()
main = DBL.putStr $ textEnvelopeToJSON Nothing $ serialise validator'

Haskell lazy evaluation

PureScript lazy evaluation

Breakthrough

Exercise

Use the compiled plutus core in a Cardano preview net transaction

Bootstrap

git clone https://github.com/input-output-hk/cardano-world.git
cd cardano-world

Cardano Node

# User interface
nix run github:divnix/std

# CLI
nix run github:divnix/std -- list
DATA_DIR=./data SOCKET_PATH=node.socket ENVIRONMENT=preview nix run github:divnix/std -- //cardano/entrypoints/cardano-node:run

Cardano CLI

nix run github:divnix/std -- //cardano/packages/cardano-cli:build
export CARDANO_NODE_SOCKET_PATH=./node.socket
export MAGIC="--testnet-magic 2"

./result/bin/cardano-cli address key-gen\
    --verification-key-file wallet.vkey\
    --signing-key-file wallet.skey\

./result/bin/cardano-cli address build\
    --payment-verification-key-file wallet.vkey\
    --out-file wallet.addr $MAGIC

./result/bin/cardano-cli address build $MAGIC\
    --payment-script-file hello.plutus\
    --out-file hello.addr

./result/bin/cardano-cli query tip $MAGIC
./result/bin/cardano-cli query protocol-parameters $MAGIC --out-file protocol-parameters.json
./result/bin/cardano-cli query utxo $MAGIC --address $(cat wallet.addr)
./result/bin/cardano-cli query utxo $MAGIC --address $(cat hello.addr)

./result/bin/cardano-cli transaction build $MAGIC\
    --babbage-era\
    --tx-in FaucetTxHash#FaucetTxIx\
    --change-address $(cat wallet.addr)\
    --tx-out "$(cat hello.addr) 7000000 lovelace"\
    --tx-out-inline-datum-file unit.json\
    --tx-out-reference-script-file hello.plutus\
    --out-file tx.body

./result/bin/cardano-cli transaction build $MAGIC\
    --babbage-era --tx-in WalletTxHash#WalletTxIx\
    --tx-in-collateral TxHash#TxIx\
    --tx-in HelloTxHash#HelloTxIx\
    --spending-tx-in-reference HelloTxHash#HelloTxIx\
    --spending-plutus-script-v2\
    --spending-reference-tx-in-inline-datum-present\
    --spending-reference-tx-in-redeemer-file unit.json\
    --change-address $(cat wallet.addr)\
    --protocol-params-file protocol-parameters.json\
    --out-file tx.body

./result/bin/cardano-cli transaction sign $MAGIC\
    --tx-body-file tx.body\
    --signing-key-file wallet.skey\
    --out-file tx.signed

./result/bin/cardano-cli transaction submit $MAGIC --tx-file tx.signed

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M06-building-smart-contracts

M06-building-smart-contracts

README.md

Introduction

Getting Started

Community Support

What you should know

Nix Overlays

Example

Haskell

Differences between Haskell and PureScript

Haskell Nix

Why Haskell Nix

Bootstrap

Source code and cabal

Nix flake

Hix options

Outputs

Build and Run

Adding Plutus

Bootstrap

flake.nix

hello.cabal and cabal.project

hello.hs

Breakthrough

Exercise

Bootstrap

Cardano Node

Cardano CLI

References and Links

Files

M06-building-smart-contracts

Directory actions

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Latest commit

History

M06-building-smart-contracts

Folders and files

parent directory

README.md

Introduction

Getting Started

Community Support

What you should know

Nix Overlays

Example

Haskell

Differences between Haskell and PureScript

Haskell Nix

Why Haskell Nix

Bootstrap

Source code and cabal

Nix flake

Hix options

Outputs

Build and Run

Adding Plutus

Bootstrap

flake.nix

hello.cabal and cabal.project

hello.hs

Breakthrough

Exercise

Bootstrap

Cardano Node

Cardano CLI

References and Links