nim-eth-contracts/README.md

# Ethereum smart contracts in Nim

Disclaimer: WIP

This is a sample of how building eWASM contracts in Nim is possible.
Requirements:
* clang 7.0 or later with WebAssembly support. Most likely has to be built manually.
* 32bit version of libc. On linuxes it is usually provided by the package manager.
* `wasm2wat` and `wat2wasm` from [wabt (WebAssembly binary toolkit)](https://github.com/WebAssembly/wabt). They need to be in the `PATH`.
* [optional] [wasm-gc](https://github.com/alexcrichton/wasm-gc) optimizer

## Compiling examples
```
export WASM_LLVM_BIN=/path/to/llvm/bin/folder
nimble examples
```

## Troubleshooting
* **Emscripten doesn't work!** It is not expected to. Use clang with wasm target enabled.
* **clang is difficult to build.** No, it's easy. Follow these steps:
```
tag=release_70
INSTALL_PREFIX=$(pwd)/llvm-wasm
git clone --depth 1 --branch $tag https://github.com/llvm-mirror/llvm.git
cd llvm/tools
git clone --depth 1 --branch $tag https://github.com/llvm-mirror/clang
git clone --depth 1 --branch $tag https://github.com/llvm-mirror/lld
cd ..
mkdir build
cd build
cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$INSTALL_PREFIX -DLLVM_TARGETS_TO_BUILD= -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly ..
make -j 4 install
```
* **C compiler errors: headers not found.** Make sure you have 32bit libc installed and visible to your clang.

## License

Licensed and distributed under either of

* MIT license: [LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT

or

* Apache License, Version 2.0, ([LICENSE-APACHEv2](LICENSE-APACHEv2) or http://www.apache.org/licenses/LICENSE-2.0)

at your option. This file may not be copied, modified, or distributed except according to those terms.