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Program Languages for Script

We have learned what a Script is and how a Script works. So, how do we write a Script then? What kind of programming language do I need to use?

Unlike other blockchains, the CKB-VM resembles a real mini-computer based on RISC-V, so the CKB Script code also looks like a normal Unix-style executable program that we run on a computer.

You can actually write Scripts in any programming language you want, as long as you have the proper toolchain.

However, at the current stage, we recommend that you use Rust to write CKB Scripts since it has a complete toolchain to work with CKB.

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We will use Rust as the programming language across the tutorials on this website.

Rust​

Rust can easily compile the source code to a RISC-V target, allowing the code to be executed on CKB-VM.

We have also built some useful Rust libraries and template tools to help developers build Script:

C​

You can also use C language and GCC to write and compile CKB Scripts to RISC-V binaries.

Some of our developers have used this way to build Scripts like sUDT and xUDT. You can check ckb-production-scripts for reference.

JavaScript, Golang, Ruby, Lua, Python...Too?​

Since the CKB-VM is akin to a real mini-computer, there's no reason you can't run different programming languages on this mini-computer, right?

The answer is yes, you can run code written in any programming language on CKB. The way it works is that you first deploy a language-specific dependency as a Script on CKB, then run your code on top of this Script, and boom, it just works!

Take JavaScript, for example. All we need to do is take a JavaScript implementation for the embedded system, e.g., duktape, compile it from C to RISC-V binary, put it on-chain, and then boom, we can run JavaScript in CKB! Since we are working with a real mini-computer here, there’s no stopping us from embedding another VM as a CKB Script to the CKB VM, and exploring this VM on top of VM path.

Expanding from this path, we can also have Ruby on CKB via mruby, and we could even have Bitcoin Script or EVM on-chain if we just compile their VMs and put them on-chain.

If you would like to explore such paths, you can check the following two examples:

Yes, I Know This Is Possible, But Won’t a VM on Top of a VM Be Slow?​

The answer really depends on your use case. Saying whether this will be slow isn't possible without actual benchmarks, which themselves are not meaningful unless applied to a real use case with standard hardware requirements. So, we'll need to wait and see if this really becomes an issue.

Besides, we are actively working in this field to optimize both the CKB VM and the VMs running on top of the CKB VM to make them faster and more efficient :P

But What If I Still Want to Use a Script-Dedicated Language?​

If you come from the Ethereum community, you might be accustomed to using a dedicated programming language to write smart contracts, like Solidity.

You might wonder if there is a similar option for CKB Scripts. Indeed, there is a dedicated programming language for CKB Scripts developed by the CKB community called Cell-Script. It is still in the early stages, but feel free to try it out and provide feedback to the community.