Welcome to **Splash** - a fast, lightweight and flexible Swift syntax highlighter. It can be used to generate code sample HTML for a blog post, to turn a string of Swift code into a fully syntax highlighted image, or to build custom developer tools.
Splash can be used either as a library in your own Swift Package Manager-powered tool or script, or by using one of the four built-in command line tools that act as frontends for the Splash library.
If you're using [Publish](https://github.com/JohnSundell/Publish), then there's an official plugin that makes it easy to integrate Splash into your website:
The easiest way to get started building things with Splash is to use one of the four built-in command line tools that each enable you to use Splash in different ways.
`SplashHTMLGen` uses Splash's HTML output format to generate an HTML string from Swift code. You simply pass it the code you want to highlight as an argument and HTML is returned as standard output.
To be as flexible as possible, Splash doesn't hardcode any colors or other CSS attributes in the HTML it generates. Instead it simply assigns a CSS class to each token. For an example of a CSS file that can be used to style Splash-generated HTML, see [Examples/sundellsColors.css](https://github.com/JohnSundell/Splash/blob/master/Examples/sundellsColors.css).
When rendering your outputted html, make sure to wrap your output code in the `<pre>` and `<code>` tags and properly link to your `.css` file. Like this:
For more information about HTML generation with Splash and how to customize it, see `HTMLOutputFormat` [here](https://github.com/JohnSundell/Splash/blob/master/Sources/Splash/Output/HTMLOutputFormat.swift).
`SplashMarkdown` builds on top of `SplashHTMLGen` to enable easy Splash decoration of any Markdown file. Pass it a path to a Markdown file, and it will iterate through all code blocks within that file and convert them into Splash-highlighted HTML.
Just like the HTML generated by `SplashHTMLGen` itself, a CSS file should also be added to any page serving the processed Markdown, since Splash only adds CSS classes to tokens — rather than hardcoding styles inline. See the above `SplashHTMLGen` documentation for more information.
Here’s an example call to decorate a Markdown file at the path `~/Documents/Article.md`:
```
$ SplashMarkdown ~/Documents/Article.md
```
The decorated Markdown will be returned as standard output.
Highlighting can be skipped for any code block by adding `no-highlight` next to the block’s opening row of backticks — like this: *“```no-highlight”*.
`SplashImageGen` uses Splash to generate an `NSAttributedString` from Swift code, then draws that attributed string into a graphics context to turn it into an image, which is then written to disk.
*`SplashImageGen` is currently only available on macOS.*
#### SplashTokenizer
The final built-in command line tool, `SplashTokenizer`, is mostly useful as a debugging tool when working on Splash - but can also be interesting to use in order to see how Splash breaks down code into tokens. Given a string of Swift code, it simply outputs all of its components (excluding whitespaces).
To include Splash in your own script or Swift package, [add it as a dependency](#installation) and use the `SyntaxHighlighter` class combined with your output format of choice to highlight a string of code:
```swift
import Splash
let highlighter = SyntaxHighlighter(format: HTMLOutputFormat())
let html = highlighter.highlight("func hello() -> String")
```
Splash ships with two built-in output formats - HTML and `NSAttributedString`, but you can also easily add your own by implementing the `OutputFormat` protocol.
## Installation
Splash is distributed as a Swift package, making it easy to install for use in scripts, developer tools, server-side applications, or to use its built-in command line tools.
To install Splash for use in a Swift Package Manager-powered tool or server-side application, add Splash as a dependency to your `Package.swift` file. For more information, please see the [Swift Package Manager documentation](https://github.com/apple/swift-package-manager/tree/master/Documentation).
Splash is developed completely in the open, and your contributions are more than welcome. It's still a very new project, so I'm sure there are bugs to be found and improvements to be made - and hopefully we can work on those together as a community.
This project does not come with GitHub Issues-based support, and users are instead encouraged to become active participants in its continued development — by fixing any bugs that they encounter, or by improving the documentation wherever it's found to be lacking.
To read more about suggested workflows when contributing to Splash, how to report bugs and feature requests, as well as technical details and an architectural overview - check out the [Contributing Guide](https://github.com/JohnSundell/Splash/blob/master/CONTRIBUTING.md).
I had a lot of fun building Splash, and I'm looking forward to continue working on it in the open together with you! I hope you'll like it and that you'll find it useful. Let me know what you think on [Twitter](https://twitter.com/johnsundell) 😊
