Huff is a low-level programming language designed for developing highly optimized smart contracts that run on the Ethereum Virtual Machine (EVM). Huff does not hide the inner workings of the EVM. Instead, Huff exposes its programming stack to the developer for manual manipulation.
Rather than having functions, Huff has macros - individual blocks of bytecode that can be rigorously tested and evaluated using the Huff runtime testing suite.
Initially developed by the Aztec Protocol team, Huff was created to write Weierstrudel. Weierstrudel is an on-chain elliptical curve arithmetic library that requires incredibly optimized code that neither Solidity nor Yul could provide.
While EVM experts can use Huff to write highly-efficient smart contracts for use in production, it can also serve as a way for beginners to learn more about the EVM.
Make sure you have the following programs installed:
This is how to create the contract bytecode to output Hello, World! in Huff.
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Install Huff globally using NPM:
npm install -g huffc
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Create a file called
hello-world.huff
and enter the following content:#define macro MAIN() = takes (0) returns (0) { 0x48656c6c6f2c20776f726c6421 0x00 mstore // Store "Hello, World!" in memory. 0x1a 0x00 return // Return 26 bytes starting from memory pointer 0. }
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Use
huffc
to compile the contract and output bytecode:huffc hello-world.huff --bytecode
This will output something like:
6100168061000d6000396000f36c48656c6c6f2c20776f726c6421600052601a6000f3
Run huffc --help
to view a full list of arguments:
huffc --help
> Usage: huffc [options]
>
> Options:
> -V, --version output the version number
> -V, --version Show the version and exit
> --base-path <path> The base path to the contracts (default: "./")
> --output-directory <output-dir> The output directory (default: "./")
> --bytecode Generate and log bytecode (default: false)
> -o, output The output file
> -p, --paste Paste the output to the terminal
> -h, --help display help for command