# yang 陽

[![Build Status](https://travis-ci.com/amosjyng/yang.svg?branch=main)](https://travis-ci.com/amosjyng/yang)

Yang is a rudimentary, experimental code generator. Yang is both used by, and depends on, [Yin](https://crates.io/crates/zamm_yin) for code generation. See [`yin.md`](yin.md) for an in-depth description of its internals.

This crate is named `zamm_yang` for consistency with `zamm_yin`. However, the name for this tool is just `yang` for all intents and purposes within the ZAMM universe.

## Usage

First, add `yin` and `yang` as build dependencies. Then, define your [`build.rs`](examples/build.rs) for concept generation, and your [`main.rs`](examples/result/main.rs) to use the generated concepts (examples linked). Make sure to initialize the newly generated concepts on KB startup.

### Literate programming

You can use [ZAMM](https://crates.io/crates/zamm) to automatically use Yang to generate code out of READMEs.

### Semver

Semver "backwards compatibility" will be interpreted to mean any changes that do not break Yin and Yang's release builds. For example, there may be many changes in the public API in between Yang versions `0.x.0` and `0.x.y`. But so long as the Yin and Yang releases that depend on `0.x.0` do not break, and the releases that depend on the most recent `0.x.y` version also do not break, this will be considered "backwards compatible" for all practical purposes.

Note that this means Yang version `0.x.0` will itself be exempt from this check, since Yang `0.x.0` will depend on Yang `0.x-1.y`, and that dependency will of course be a breaking change.

## Development

Note that due to Yang using its autogeneration capabilities on itself, it requires a pre-existing binary of itself in order to build its current version. The `build.rs` script will attempt to download one from Bintray if it isn't found locally. If none of the versions of Bintray are available for your platform, you can bootstrap Yang by building each version consecutively and setting the `YANG_BINARY` environment variable to the location of the newly built `yang` executable.