Embed the Dart Sass compiler in your Swift program. Write stylesheet importers and SassScript functions in Swift.
This package provides a Swift language interface to a separate Sass
implementation. The DartSass module lets you access
Dart Sass,
the most up to date implementation of the Sass language. It runs the
Dart Sass compiler as a separate process
and communicates with it using the
Sass embedded protocol. If you
come across another implementation of the 'compiler' side of the protocol then
that should work fine too.
This package doesn't support LibSass right now. More info.
Minimally:
import DartSass
let compiler = try Compiler()
let results = try await compiler.compile(fileURL: scssFileURL)
print(results.css)Although the compiler output is more structured, if this is all you want to do
then you're probably better off running the binary directly. The reason to use
this package is to provide custom implementations of @use rules to load
content, and custom functions to provide application-specific behavior:
struct ExtrasImporter: Importer {
func canonicalize(importURL: String) async throws -> URL? {
guard importURL == "extras" else {
return nil
}
return URL(string: "custom://extras")
}
func load(canonicalURL: URL) async throws -> ImporterResults {
ImporterResults(my_extras_stylesheet)
}
}
let customFunctions: SassFunctionMap = [
"userColorForScore($score)" : { args in
let score = try args[0].asInt()
return SassColor(...)
}
]
let results = try await compiler.compile(
fileURL: scssFileURL,
importers: [
.loadPath(sassIncludeDirectoryFileURL),
.importer(ExtrasImporter())
],
functions: customFunctions
)// stylesheet
@use "extras";
.score-mid {
color: userColorForScore(50);
}DartSass is built on NIO but the user
interface is entirely Swift 5.5 async-await.
- API documentation
- Dash docset feed or direct download
- Swift 5.7
- macOS 13+ (tested on macOS 13.2 x64)
- Linux (tested on Ubuntu 22.04 x64)
- Embedded Sass Protocol version 2.3.0
Only with Swift Package Manager, via Xcode or directly:
Package dependency:
.package(name: "swift-sass",
url: "https://github.com/johnfairh/swift-sass.git",
from: "2.0.0")Target dependency:
.product(name: "DartSass", package: "swift-sass"),The Swift package bundles the Dart Sass compiler for macOS and Linux (specifically Ubuntu Focal/20.04 64-bit) both x86_64 and arm64. The correct binary is selected at build time. The selection is made based on the host architecture though, so if you want to cross-compile you'll need to assemble the results manually.
For other platforms you will need to either download the correct version from the release page or build it manually, ship it as part of your program's distribution, and use this initializer.
There is no need to install a Dart runtime or SDK as part of this, the
dart-sass-embedded program is standalone. The version required is shown in
the VERSION_DART_SASS file.
LibSass is the C++ implementation of Sass. In recent years it has fallen behind the specification and reference implementations, and was deprecated in 2020. However, work is underway to revive the project and it may be that LibSass 4 emerges as an alternative Sass implementation with the same level of language support as Dart Sass. As of spring 2023 this revival effort is on hold: I'm not holding my breath.
See the experimental libsass4 branch
for the current state of development: if LibSass itself manages to get to a
relased V4 then this swift-sass package will support it as an alternative
integration.
Welcome: open an issue / johnfairh@gmail.com / @johnfairh@mastodon.social
Distributed under the MIT license.