Clarc

Clarc compiles Clarity smart contracts into Ethereum virtual machine (EVM) bytecode.

More specifically, the Clarc compiler, called clarc, parses .clar files and compiles them into an equivalent EVM bytecode program that runs on the Ethereum blockchain.

Note: Here be dragons. This is a pre-alpha, work-in-progress project. Assume nothing works, and you may be pleasantly surprised on occasion.

Installation

Binary Downloads

The latest release binaries for macOS and Linux are available here:

To install, just download and untar the archive and then copy the resulting binary to /usr/local/bin, as follows:

macOS

wget https://github.com/weavery/clarc/releases/download/0.5.0/clarc-0.5.0-macos.tar.gz

tar xf clarc-0.5.0-macos.tar.gz

sudo install clarc-0.5.0-macos /usr/local/bin/clarc

Linux

wget https://github.com/weavery/clarc/releases/download/0.5.0/clarc-0.5.0-linux.tar.gz

tar xf clarc-0.5.0-linux.tar.gz

sudo install clarc-0.5.0-linux /usr/local/bin/clarc

Source Code

If you wish to try out the latest and greatest Clarc, you will need to build it from source code yourself, which entails setting up an OCaml development environment. Reserve at least half an hour of time and see further down in this document for the particulars.

Usage

To view Clarc's built-in man page that documents all command-line options, run:

clarc --help

Compiling to opcode

To compile the Clarity counter.clar example contract to programmer-readable output, known as symbolic opcode, run:

clarc -t opcode counter.clar

The previous writes out the compiled program to standard output, which is helpful during development and debugging.

Compiling to bytecode

To compile the Clarity counter.clar example contract to deployable bytecode, run:

clarc -t bytecode counter.clar

Alternatively, you can specify an output file name in the usual way, with the target type inferred from the output file extension (.bin for bytecode, in keeping with the Solidity compiler):

clarc -o counter.bin counter.clar

Deploying the contract

MyEtherWallet is the easiest way to deploy the generated contracts:

Examples

Supported Contracts

The currently tested contracts, deployed to the public Ropsten testnet, are:

Contract ID	Contract Code	Contract Bytecode	Contract ABI
0x8a90b1e93020933295b3bd4ce2317062319351d4	`counter.clar`	`counter.bin`	`counter.json`
0x2e2487c64b1420111e8d66d751f75f69515c5476	`kv-store.clar`	`kv-store.bin`	`kv-store.json`
0x9a1b29fc432af1e37af03ed2fee00d742ff7372f	`panic.clar`	`panic.bin`	`panic.json`

MyEtherWallet is the easiest way to interact with these deployed contracts.

Example: Counter

`counter.clar`

(define-data-var counter int 0)

(define-read-only (get-counter)
  (ok (var-get counter)))

(define-public (increment)
  (begin
    (var-set counter (+ (var-get counter) 1))
    (ok (var-get counter))))

(define-public (decrement)
  (begin
    (var-set counter (- (var-get counter) 1))
    (ok (var-get counter))))

`counter.opcode`

$ clarc counter.clar -t opcode
PUSH1 0x00 PUSH1 0x00 SSTORE PUSH1 0x64 DUP1 PUSH1 0x10 PUSH1 0x00 CODECOPY
PUSH1 0x00 RETURN PUSH1 0xe0 PUSH1 0x02 EXP PUSH1 0x00 CALLDATALOAD DIV DUP1
PUSH4 0x8ada066e EQ PUSH1 0x28 JUMPI DUP1 PUSH4 0xd09de08a EQ PUSH1 0x36
JUMPI DUP1 PUSH4 0x2baeceb7 EQ PUSH1 0x4d JUMPI STOP JUMPDEST POP PUSH1 0x00
SLOAD PUSH1 0x00 MSTORE PUSH1 0x20 PUSH1 0x00 RETURN STOP JUMPDEST POP
PUSH1 0x01 PUSH1 0x00 SLOAD ADD PUSH1 0x00 SSTORE PUSH1 0x00 SLOAD PUSH1 0x00
MSTORE PUSH1 0x20 PUSH1 0x00 RETURN STOP JUMPDEST POP PUSH1 0x01 PUSH1 0x00
SLOAD SUB PUSH1 0x00 SSTORE PUSH1 0x00 SLOAD PUSH1 0x00 MSTORE PUSH1 0x20
PUSH1 0x00 RETURN STOP

`counter.bin`

$ clarc counter.clar -t bytecode
600060005560648060106000396000f360e060020a6000350480638ada066e146028578063d09de08a1460365780632baeceb714604d57005b5060005460005260206000f3005b5060016000540160005560005460005260206000f3005b5060016000540360005560005460005260206000f300

Design

Clarc is written in OCaml, an excellent programming language for crafting compiler toolchains.

Clarc is a standard multi-pass compiler consisting of the following stages:

The Clarity parser and abstract syntax tree (AST) are maintained as a subproject in an OCaml library called Clarity.ml. The library enables anyone familiar with OCaml to quickly and easily develop more best-of-class tooling for Clarity contracts.

Lexical analysis

See Clarity.ml's lexer.mll for the lexical analyzer source code.

Syntactic analysis

See Clarity.ml's parser.mly and parse.ml for the parser source code.

Semantic analysis

See Clarity.ml's grammar.ml for the structure of the Clarity AST.

Development

This section documents how to get set up with a development environment for building Clarc from source code. It is only of interest to people who wish to contribute to Clarc.

Prerequisites

The following baseline tooling is required in order to build Clarc from source code:

Git
OCaml 4.11+
OPAM
Dune
Docker (for release builds only)

We would recommend you don't install OCaml from a package manager.

Rather, get set up with OPAM and then let OPAM install the correct version of OCaml as follows:

opam init -c 4.11.1        # if OPAM not yet initialized
opam switch create 4.11.1  # if OPAM already initialized

Once OPAM and OCaml are available, install Dune as follows:

opam install dune

Dependencies

The following OCaml tools and libraries are required in order to build Clarc from source code:

Alcotest for unit tests
Clarity.ml for parsing Clarity code
Cmdliner for the command-line interface
Cppo for code preprocessing
Cryptokit for the Keccak-256 hash function
ISO8601 for date handling
Num for 128-bit integers
Ocolor for terminal colors

These aforementioned dependencies are all best installed via OPAM:

opam install -y alcotest cmdliner cppo cryptokit iso8601 num ocolor
opam pin add -y clarity-lang https://github.com/weavery/clarity.ml -k git

Running the program

alias clarc='dune exec bin/clarc/clarc.exe --'

clarc --help

Installing from source code

git clone https://github.com/weavery/clarc.git

cd clarc

dune build

sudo install _build/default/bin/clarc/clarc.exe /usr/local/bin/clarc

Acknowledgments

We thank the Stacks Foundation for sponsoring the development of Clarc.

We thank Blockstack and Algorand for having developed the Clarity language, an important evolution for the future of smart contracts.

Status

Supported Clarity features

Feature	Type	Status	Notes
`*`	function	✅	For two parameters. Without overflow checking.
`+`	function	✅	For two parameters. Without overflow checking.
`-`	function	✅	For two parameters. Without underflow checking.
`/`	function	✅	For two parameters. Without division-by-zero checking.
`<`	function	✅
`<=`	function	✅
`>`	function	✅
`>=`	function	✅
`and`	operator	✅	For two parameters.
`append`	function	✅
`as-contract`	operator	🚧
`as-max-len?`	operator	🚧
`asserts!`	function	✅
`at-block`	operator	❌	Not implemented yet.
`begin`	operator	🚧
`block-height`	keyword	✅
`buff`	literal	✅
`burn-block-height`	keyword	✅
`concat`	function	✅	Only for lists.
`contract-call?`	operator	❌	Not implemented yet.
`contract-caller`	keyword	✅
`contract-of`	operator	❌	Not implemented yet.
`default-to`	function	✅
`err`	function	✅
`false`	literal	✅
`filter`	function	🚧
`fold`	function	🚧
`ft-get-balance`	function	🚧
`ft-mint?`	function	🚧
`ft-transfer?`	function	🚧
`get`	operator	🚧
`get-block-info?`	operator	❌	Not implemented yet.
`hash160`	function	✅
`if`	operator	✅
`impl-trait`	operator	❌	Not implemented yet.
`int`	literal	✅
`is-eq`	function	✅	For two parameters.
`is-err`	function	✅
`is-in-regtest`	keyword	✅
`is-none`	function	✅
`is-ok`	function	✅
`is-some`	function	✅
`keccak256`	function	✅
`len`	function	✅	Only for literals.
`let`	operator	🚧
`list`	function	✅
`map`	function	🚧
`map-delete`	function	🚧
`map-get?`	function	✅
`map-insert`	function	🚧
`map-set`	function	🚧
`match`	operator	✅
`mod`	function	✅	Without division-by-zero checking.
`nft-get-owner?`	function	🚧
`nft-mint?`	function	🚧
`nft-transfer?`	function	🚧
`none`	literal	✅
`not`	function	✅
`ok`	function	✅
`or`	operator	✅	For two parameters.
`pow`	function	✅	Without overflow checking.
`principal`	literal	🚧
`principal-of?`	function	🚧
`print`	function	✅	Only for literals. Without a meaningful return value.
`secp256k1-recover?`	function	❌	Not implemented yet.
`secp256k1-verify`	function	❌	Not implemented yet.
`sha256`	function	✅
`sha512`	function	❌	Not implemented yet.
`sha512/256`	function	❌	Not implemented yet.
`some`	function	✅
`sqrti`	function	❌	Not implemented yet.
`string`	literal	✅
`stx-burn?`	function	❌	Not supported.
`stx-get-balance`	function	❌	Not supported.
`stx-liquid-supply`	keyword	❌	Not supported.
`stx-transfer?`	function	❌	Not supported.
`to-int`	function	🚧
`to-uint`	function	🚧
`true`	literal	✅
`try!`	function	✅
`tuple`	operator	🚧
`tx-sender`	keyword	✅
`uint`	literal	✅
`unwrap!`	function	✅
`unwrap-err!`	function	✅
`unwrap-err-panic`	function	✅
`unwrap-panic`	function	✅
`use-trait`	operator	❌	Not implemented yet.
`var-get`	operator	✅
`var-set`	operator	✅
`xor`	function	✅

Legend: ❌ = not supported. 🚧 = work in progress. ✅ = supported.