Plutus Playground Smart Contract

Playground.hs

import Data.Text qualified as T
import Playground.Contract
import Plutus.Contract
import PlutusTx.Prelude
import Prelude qualified as Haskell

-- | A 'Contract' that logs a message.
hello :: Contract () EmptySchema T.Text ()
hello = logInfo @Haskell.String "Hello, world"

endpoints :: Contract () EmptySchema T.Text ()
endpoints = hello

-- 'mkSchemaDefinitions' doesn't work with 'EmptySchema'
-- (that is, with 0 endpoints) so we define a
-- dummy schema type with 1 endpoint to make it compile.
-- TODO: Repair 'mkSchemaDefinitions'
type DummySchema = Endpoint "dummy" ()

mkSchemaDefinitions ''DummySchema

$(mkKnownCurrencies [])

Simulation.json

[0,[]]