SewUp

• Rust crate
• Open source at Github
• Utilize Ethereum WebAssembly
• Contract Dev as Backend (CDAB)
  
• Rusty api
• Learn more with previous slides

Key Value Storage

• Object storage
• Flexible
• Easy to use
• KV feature of SewUp
• Reading material

Hangman

• A game for learning phrase
• Sample code
• Use Sewup kv feature

Rules

1. Every account can set only a word as the puzzle, a sentence as the reward for people solve the puzzle, and a hint for people
2. Everyone can get the information of the puzzle (the length of words and the hint).
3. Everyone guess one char, for example p, and he will get a partial string like -pp--.
4. Everyone can guess the word, if correct, he will see the sentence.

Init project

1. Install Rust

   curl --proto '=https' --tlsv1.2 -sSf \ https://sh.rustup.rs | sh

2. Install cargo sewup

   cargo install cargo-sewup

3. Initialize project

   cargo sewup init -m rusty

4. Add kv feature

   features = [ "kv" ]

Check out Commit f82cceb

Check out Commit 90ee3a3

Setup constructor

Check out Commit 52832e4

Objective

1. Define datastructure
2. Initialize storage when deploy

1. Every account can set only a word as the puzzle, a sentence as the reward for people solve the puzzle, and a hint for people

Setup constructor

Check out Commit 52832e4

1. Use cargo test to validate you code
2. If _compile_runtime_test fail,
   run cargo build --target=wasm32-unknown-unknown
3. If _compile_constructor_test fail,
   run cargo build --features=constructor --target=wasm32-unknown-unknown

Tips for developing constructor

Setup Puzzle

Check out Commit 11bf360

Objective

1. Handle the data from client ewasm_input_from!
2. Storage data on chain, commit
3. Test with specific caller, by

Get Puzzle Info

Check out Commit 8726c45

Objective

1. Use EwasmAny for return different
2. Initial Input structure, just like form in HTTP

Guess Char

Check out Commit 5b8cd22

Objective

1. Modify the Input structure
2. Initial Input structure, just like form in HTTP
3. Update testcase

Guess Word

Check out Commit 12a6ad4

Objective

1. Modify the Input structure
2. Initial Input structure, just like form in HTTP
3. Update testcase

Well Done

Really Easy with SewUp

Validate Puzzle

• Prevent a puzzle with phrase or sentence
• Issue #1
• O Apple
• X An apple a day

Introduce thiserror

• Try to introduce thiserror crate
• Issue #2
• X anyhow::anyhow!("message")
• X panic!("message")

Blockchain bring TRUST to the world

Rust is the stem of TRUST

SewUp base on Rust and Ewasm helps you build great blockchain applications

Thanks for listening

Star the project if you like it

https://github.com/second-state/SewUp

There are also help want issues and good first issues

Interested in VM?

WasmEdge is welcom to contribute

https://github.com/WasmEdge/WasmEdge

Q&A

Sewup sew your ethereum project up to the world