This SBT plugin generates a Scala source file that represents the directory structure of a given file system directory.

For example, given a directory with the following structure:

base/
  file1.jpg
  file2.jpg
  sub/
    file3.jpg

The plugin generates (roughly) the following Scala object:

object AppAssets {
  def file1_jpg: String = "file1.jpg"
  def file2_jpg: String = "file2.jpg"
  object sub {
    def file3_jpg: String = "sub/file3.jpg"
  }
}

Now you can refer to a given file path without writing the string literal by hand:

AppAssets.sub.file3_jpg // returns "sub/file3.jpg"

Furthermore, if the file is deleted or moved from the file system, any code that references the file will no longer compile.

Add the following settings in plugins.sbt:

addSbtPlugin("com.malliina" % "sbt-filetree" % "0.4.1")

Enable FileTreePlugin in your project:

val myProject = Project("demo", file("."))
  .enablePlugins(com.malliina.sbt.filetree.FileTreePlugin)

Specify the source directories for the file tree traversal and corresponding destination objects to write:

import com.malliina.sbt.filetree.DirMap
fileTreeSources += DirMap(baseDirectory.value / "appfiles", "com.malliina.filetree.AppFiles")

Now when you compile, the build generates source code that defines an object com.malliina.filetree.AppFiles, where each member is a file or directory under baseDirectory / appfiles.

By default, each file path is represented as a String. You can supply a function as a third paramater to a DirMap that transforms each file path:

DirMap(baseDirectory.value / "appfiles", "com.malliina.filetree.AppFiles", "com.malliina.Code.transform")

Where transform is a unary function of type String => T.