import $file and import $ivy

build.mill (download, browse)

package build
import mill._, scalalib._
import $ivy.`com.lihaoyi::scalatags:0.12.0`, scalatags.Text.all._

object `package` extends RootModule with ScalaModule {
  def scalaVersion = "2.13.8"

  def ivyDeps = Agg(ivy"com.lihaoyi::os-lib:0.10.7")
  def htmlSnippet = T{ div(h1("hello"), p("world")).toString }
  def resources = Task.Sources{
    os.write(Task.dest / "snippet.txt", htmlSnippet())
    super.resources() ++ Seq(PathRef(Task.dest))
  }
}

This example illustrates usage of import $ivy. import $ivy lets you import ivy dependencies into your build.mill, so you can use arbitrary third-party libraries at build-time. This makes lets you perform computations at build-time rather than run-time, speeding up your application start up. In this case, we move the Scalatags rendering logic to build time, so the application code gets a pre-rendered string it can directly print without further work.

> mill compile
compiling 1 Scala source...
...

> mill run
generated snippet.txt resource: <div><h1>hello</h1><p>world</p></div>

> mill show assembly
".../out/assembly.dest/out.jar"

> ./out/assembly.dest/out.jar # mac/linux
generated snippet.txt resource: <div><h1>hello</h1><p>world</p></div>