TaoHe is a collection of nestable smart contract resources that can be used to create secure on-chain applications on MoveVM blockchains, such as Diem. Resources can be nested like a Russian doll (матрёшка), or Chinese boxes (套盒), the namesake of this project. ▣ is used as the logo, since it depicts a box inside another box.
Tao is a simple Move resource that has been designed to be nested inside other taos. TaoHe is a collection of taos, and a special Root resource that can be used to store a resource directly into an account (taos themselves can be stored into resources only, for simplicity).
Example: You could place Diem tokens into a time locked tao, and place that inside an NFT tao, effectively creating a non-fungible time locked token.
Participate to TaoHe discussion on Diem Community.
Taos are meant to form disposable structures that contain a meaningful resource (such as Diem tokens). In order to access the resource in question, taos must be dismantled. A new tao can be created though, if so desired. Nesting taos inside each other can form complicated logics, such as time locked non-fungible tokens.
Keeping code footprint per each tao in minimum is vital for safer code, and is simpler to audit. Keeping taos simple also shifts the code footprint to scripts, which are easier to develop and update than smart contracts.
Tao's lifespan is divided into three separate phases, listed here chronologically:
- Wrap: Tao is created by placing a resource into the tao, and initializing it with the constructor's arguments.
- Wrapped: In the current design taos are static, with support of immutable references to the resource(s) inside.
- Unwrap: When conditions are satisfied (such as passed time), the resource inside the tao is given away, and the tao is destroyed.
Taos are not meant to replace specialized smart contract development for complicated applications, but can be used as part of one.
TaoHe is developed with Microsoft's Visual Studio Code and the Move Language plugin.
We use Dove build system 1.5.4 for building, package management, dependencies, formal verification and testing. After successful Dove installation, you can just run:
dove build
Jumpstart:
dove run -v "dummy()"(replacedummywith any function residing in scripts/)
Every tao has formal verification specs embedded. You can run the formal verification by running:
dove prove
You'll need
boogieandz3solver, which can be easily installed with Diem's development setup script:./scripts/dev_setup.sh -y. If you want to change the default paths, edit./prover-env.toml.
Warning: Although every tao has formal verification specs,
move-proveris still under development, and might have some limitations. Please see each source file for more information.
You can also add TaoHe as a dependency for your Dove based project by adding these lines to your project's Move.toml:
[addresses]
TaoHe = "0x2f66c09143acc52a85fec529a4e20c85"
[dependencies.TaoHe]
git = "https://github.com/taoheorg/taohe"
rev="...."
Warning: Due to signed commits, commit hash should be used since it cannot be spoofed. After you know which TaoHe version you want to use, replace
revwith your desired commit hash.
DX is not good at the moment since types must be known beforehand, and written in their full form, resulting in lengthy inscrutable lines of code. This could be solved by creating an intermediate Yaml based description language which could be used to generate transaction scripts and transaction script functions (a new Move feature).
See doc/ for dove build -d generated documentation.
This repository is released under the Apache License 2.0, and is copyrighted to Solarius Intellectual Properties Ky (Forssa, Finland, EU). See Move.toml for more information on dependencies. No warranty or fitness for a particular purpose provided, as stipulated in the License.
Smart contracts are mission critical and as such should always originate from trusted sources. That's why every commit on master is signed with Ville's GPG key. Upstream repository is here and the official webpage is at www.taohe.org.