Advanced Clarity Smart Contract Examples

Stacks_Joe · January 29, 2021, 5:00pm

Hey there, Everyone!

Happy Friday! Just wanted to share a little curated smart contract list I assembled today. They are what I would consider the most robust, substantive Clarity smart contracts that have been developed for Stacks 2.0 so far. These should act as sterling examples of the potential of the language, and I would recommend any beginners comb through some code to begin grasping advanced usage.

SWAPR

An automated token exchange modeled after Uniswap in Clarity for Stacks 2.0.

FLEXR

A reimplementation of the Ampleforth Token, Oracle and Geyser.

ClarityDAO

A conversion of Ethereum’s Moloch DAO in Clarity.

SRC-20 Token Standard Trait

A token standard in Clarity similar to Ethereum’s ERC-20

github.com

psq/flexr/blob/master/contracts/src20-trait.clar

;; Time for a Stacks Request for Comment, the 20th edition...
;; The function needed by tokens compatible with swapr, and the geyser
;; a subset of ERC20 methods
(define-trait src20-trait
  (
    ;; Transfer from the caller to a new principal
    (transfer (principal uint) (response bool uint))

    ;; the human readable name of the token
    (name () (response (string-ascii 32) uint))

    ;; the ticker symbol, or empty if none
    (symbol () (response (string-ascii 32) uint))

    ;; the number of decimals used, e.g. 6 would mean 1_000_000 represents 1 token
    (decimals () (response uint uint))

    ;; the balance of the passed principal
    (balance-of (principal) (response uint uint))

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Composable Token

A composable NFT token that can be attached to, or detached from, any NFT token.

github.com

dotrungkien/clarity-composable-token/blob/master/contracts/composable-token.clar

;; Composable Non Fungible Token
(define-non-fungible-token composable-token int)

;; Storage
(define-map token-count ((owner principal)) ((count int)))
(define-map child-count ((token-id int)) ((count int)))
(define-map parent-token ((token-id int)) ((parent-id int)))
(define-map child-token ((parent-id int)) ((left-child-id int) (right-child-id int)))

;; Constant
(define-constant max-child-depth 2)
(define-constant contract-owner 'STCYMDQ2B7WPTN1NDQ1HAADCYS1RKWGQ5KF09E61)

(define-constant same-spender-err (err u1))
(define-constant not-approved-spender-err (err u2))
(define-constant failed-to-move-token-err (err u3))
(define-constant unauthorized-transfer-err (err u4))
(define-constant failed-to-mint-err (err u5))
(define-constant zero-id-err (err u6))
(define-constant failed-to-attach-err (err u7))

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NFT Marketplace

Clarity smart contract for a marketplace of tradable assets.

github.com

friedger/clarity-marketplace/blob/master/contracts/market.clar

(use-trait tradables-trait .tradables.tradables-trait)

(define-map on-sale
  {owner: principal, tradables: principal, tradable-id: uint}
  {price: uint, duration: uint}
)

(define-map offers {bid-owner: principal, owner: principal, tradables: principal, tradable-id: uint}
  {price: uint}
)

(define-map accepting-owners {tradables: principal, tradable-id: uint}
  {owner: principal}
)
(define-constant err-invalid-offer-key u1)
(define-constant err-payment-failed u2)
(define-constant err-transfer-failed u3)
(define-constant err-not-allowed u4)
(define-constant err-duplicate-entry u5)

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StackStarter

A Clarity smart contract for crowdfunding on the STX blockchain.

github.com

MarvinJanssen/stackstarter/blob/master/contracts/stackstarter.clar

;; Stackstarter version 1
;; By Marvin Janssen (2020)

;; contract version for testing
(define-constant contract-version u1)

;; contract owner
;; for testnet phase 3
;; (define-constant contract-owner tx-sender)

;; error constants
(define-constant error-general (err u1))
(define-constant error-not-owner (err u2))
(define-constant error-campaign-has-investors (err u3))
(define-constant error-campaign-does-not-exist (err u4))
(define-constant error-campaign-inactive (err u5))
(define-constant error-invest-amount-insufficient (err u6))
(define-constant error-invest-stx-transfer-failed (err u7))
(define-constant error-no-investment (err u8))
(define-constant error-campaign-already-funded (err u9))

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Non-Fungible Token

An implementation of non-fungible tokens in Clarity.

github.com

friedger/clarity-js-sdk/blob/feature/web-ide/packages/clarity-tutorials/contracts/tokens/non-fungible-token.clar

;;  copyright: (c) 2013-2019 by Blockstack PBC, a public benefit corporation.

;;  This file is part of Blockstack.

;;  Blockstack is free software. You may redistribute or modify
;;  it under the terms of the GNU General Public License as published by
;;  the Free Software Foundation, either version 3 of the License or
;;  (at your option) any later version.

;;  Blockstack is distributed in the hope that it will be useful,
;;  but WITHOUT ANY WARRANTY, including without the implied warranty of
;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;  GNU General Public License for more details.

;;  You should have received a copy of the GNU General Public License
;;  along with Blockstack. If not, see <http://www.gnu.org/licenses/>.

;; Non Fungible Token, modeled after ERC-721
(define-non-fungible-token non-fungible-token int)

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Margin Trading Failsafe

This smart contract helps facilitate a margin-trading account with built-in checking for available balance above a margin limit before authorizing new spending.

github.com

Agilan19/SB-Hacks-2021-Margin-Trading-Smart-Contract/blob/main/contracts/failsafe.clar

;; constants & errors
(define-constant origin 'ST2ZXARHZ2VGGXYYA3C9W97NAGZVJB0RAFDCHNY6E)
(define-constant err-balance-too-low (err u1))
(define-constant err-limit-reached (err u2))

;; variables
(define-data-var margin-limit int 0)
(define-data-var margin int 0)
(define-data-var balance int 0)
(define-data-var daily-limit-deposit int 1000)
(define-data-var daily-limit-withdrawal int 5000)
(define-data-var transaction-time-b-height int 1)

;; get balance in wallet
(define-public (get-balance)
    (begin
      (var-set balance (to-int (stx-get-balance tx-sender)))
      (ok (var-get balance))
    )
)

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Key-Value Store

A key-value storage map in Clarity.

github.com

friedger/clarity-smart-contracts/blob/master/contracts/experiments/kv-store.clar

(define-map store ((key principal))
  ((v1 int)
   (v2 int))
)

(define-public (get-value (key principal))
    (match (map-get? store {key: key})
        entry (ok (get v2 entry))
        (err 0)))

(define-public (set-value (key principal))
    (begin
        (map-set store {key: tx-sender} {v1: 100, v2: 7})
        (ok true)))

uint256 Library

A library for converting values into 256-bits.

Lightning Swaps

Fraud-proof swaps using Lightning.

github.com

radicleart/clarity-rstack/blob/master/contracts/lightning-swaps-v1.clar

;; Project Lightning Swaps
;; -----------------------
;; Fraud proof swaps. This contract transfers STX tokens to user on receipt of a valid
;; preimage proving payment on Lightning via LSAT protocol. 
;; The contract also registers the btc address of the user in the case were they
;; want to start stacking or at least contributing to a delegated stacking pool.

;; Constants
;; ---------
(define-constant administrator 'ST1EYJJ3V4DNRVHRWANP8S3CXJ70SFBJF2F8DH2RM)
(define-constant not-allowed u110)
(define-constant not-found u100)
(define-constant not-enough-funds u120)

;; Storage
;; -------
;; preimage-map : map of payments against recipients
(define-map preimage-map ((preimage (buff 32))) ((recipient principal) (amount uint) (paid bool)))
(define-map btc-address-map ((btc-address (buff 56))) ((stacker-address principal) (lockin-rate uint)))

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Election Voting

A basic voting election for candidates in Clarity.

github.com

elbaruni/clarity-election/blob/master/contracts/election.clar

 (define-constant admin 'SP2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKNRV9EJ7 ) ;; admin only allowed to add candidates and open or close elections
  
  (define-constant open 1 ) ;; constant to set registration / election open 
  
  (define-constant close 0 );; constant to set registration / election closed 

 (define-map Candidates ;; mapping to store all candidates and their voting count
  ((candidateId int)  )
  ((name (buff 40)) (votescount uint))) 
 
  (define-map voters ((voter principal)) ((voted uint ))) ;; mapping to store all voted address 
 
 (define-data-var numberOfCandidates int 0) ;; variable to track number of candidates
 
  (define-data-var RegistrationIsOpen int open) ;; Registration is open =1 otherwise is closed
 
  (define-data-var votingIsOpen int open) ;;voting is open=1 otherwise is closed
 
 (define-private (incrementCandidates)  ;; incress number of candidates counter
    (begin

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DualX

A collection of Clarity contracts that implement a De-Fi ecosystem of exchanges.

WRAPR

Wrapping and minting tokens.

github.com

psq/swapr/blob/master/contracts/wrapr.clar

(impl-trait 'SP2TPZ623K5N2WYF1BWRMP5A93PSBWWADQGKJRJCS.token-transfer-trait.can-transfer-tokens)

(define-data-var total-supply uint u0)

(define-fungible-token wrapped-token)

;; Total number of tokens in existence.
(define-read-only (get-total-supply)
  (ok (var-get total-supply))
)

;; get the token balance of owner
(define-read-only (balance-of (owner principal))
  (begin
    (ok (ft-get-balance wrapped-token owner))
  )
)

(define-read-only (name)
  (ok "wrapr")

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And don’t forget! You can find a spreadsheet of each and every Clarity smart contract that was developed during testnet HERE.

Gina · January 29, 2021, 5:23pm

This is awesome!!! Thanks for sharing, Joe. Amazing work by community builders . Can’t wait to see how this list evolves and these contracts get used now that Stacks 2 is live!