The ability to import other groocss files is supported by importFile, importStream, and importString methods which take a parameter map and input. Any number of variables can be passed. For example:

    def otherCss = new File('whatever/file.groovy')
    importFile otherCss.absoluteFile, linkColor: '#456789', backColor: 'black'

Within the imported groovy file, linkColor and background will be available with the given values.

For example, given that "file.groovy" has the following contents:

    a { color linkColor backgroundColor backColor }

The resulting CSS would be the following:

    a {
        color #456789;
        background-color: Black;


  • importFile - Takes in a

  • importStream - Takes an InputStream and reads it.

  • importString - Takes a String expected to be a GrooCSS DSL input.

For example, to read a file named "other.css.groovy" on the classpath (under /groocss/) do the following:

    linkColor: '#456789', backColor: 'black')

Importing with Gradle

However, you might not always know what directory to look in for files. If you want to import files using the classpath method, you should follow some additional steps (for a multi-module Gradle build):

  • Create a "src/css/groovy" and "imports/css/groocss" and tell your IDE these are also source folders.

  • Create a Main.groovy under "src/css/groovy/groovycss"

  • Create a "build.gradle" file in the current directory.

  • Create a "settings.gradle" file in the current directory with the contents: include 'imports'

  • Create a "build.gradle" file in the "imports/" directory.

  • Create a Groocss file at "imports/css/groocss/elements/a.css.groovy".

Root Build

Put the following in /build.gradle:

plugins {
    id 'groovy'
    id 'application'
mainClassName = 'groovycss.Main'
repositories { jcenter() }
sourceSets {
    main {
        groovy.srcDirs += ["$projectDir/src/css/groovy"]
dependencies {
    compile "org.groocss:groocss:1.0-M4-groovy2.5"
    runtime project(':imports')
task css(dependsOn: ['compileGroovy', ':imports:build', 'run'],
                     description: "--> Converts GrooCSS to CSS files",
                     group: 'build') {
    doFirst {
        def outputDir = "${dir}/resources/css/"


In "Main.groovy" put the following:

package groovycss
import groovy.transform.CompileStatic
import org.groocss.*
class Main {
    static void main(String[] args) {
        String dir = '.'
        String outputDir = 'resources/css/'
        def conf = new Config(prettyPrint: true, addOpera: false) // for dev
        new File("${dir}/src/css/groocss")
                .listFiles({ File f -> f.isFile() } as FileFilter)
                .each { File f -> processFile(outputDir, f, conf) }
    static void processFile(String outputDir, File f, Config conf) {
        def outputFile = new File("${outputDir}${'.groovy', '')}")
        GrooCSS.convert conf, f, outputFile

This will process all of your files under "src/css/groocss" and output the CSS in "resources/css/".

Imports Build

Within the "imports/build.gradle" file put the following:

plugins {
    id 'java'
sourceSets {
    main {
        resources {srcDir 'css/groocss/'}

Importing From Classpath

Finally, create a file under "src/css/groocss" named "root.css.groovy" and put in the following:

'root'.groocss {

This works since at runtime the files from the "imports" sub-project are included as dependencies.

Run the Build

Using Gradle (tested with Gradle 5.4.1) run gradle css from the command line.

Last updated: 31 July 2019