GrooCSS has always made static code compilation one of its priorities. However, for greatest similarity to CSS, it was necessary to use dynamic method calls (using methodMissing behind the scenes) to allow for the .styleClass syntax (and more) to work.

To support fully static code (which enables code completion in your IDE), there are several ways to define CSS selectors without resorting to any dynamic method calls.

Set Up Your IDE

First you need to setup your IDE.

  • IDEA: Create a new Module of type Groovy.

  • Eclipse: Create a new Project of type Groovy (make sure you have a Groovy plugin installed).

Create a directory, "src/css/groocss" and tell your IDE this is a source folder.

Make sure that you have a groocss JAR as a dependency in your Module or project’s definition.

Root GrooCSS

To begin a fully static GrooCSS file, you can start with 'foo'.groocss { and end with }, where "foo" should be the name of the current file.

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

'root'.groocss {
    html { color black }
    body { width 100%_ }
    'div.main-div'.sg { fontSize 2.em }
    'button1'.id { width 20.em }
    _ ** selection { color '#ffeefe' }
    $('.list li') { appearance 'none' }

The above would yield the following CSS:

html { color: Black; }
body { width: 100%; }
div.main-div { font-size: 2em; }
#button1 { width: 20em; }
::selection { color: #ffeefe; }
.list li { appearance: none; }

Note that you can mix and match many different operators and methods as long as you don’t call an undefined method.


Building is the same as already discussed.


You can always use importFile(filename) or importFile(File) to import another file.

Allowed Static Code


To keep all of your GrooCSS code statically typed, the following is allowed/static/non-dynamic code:

def myColor = c('#fe33ac')
table {
    color myColor
input['class$="test"'] = { //becomes input[class$="test"]
    background yellow
sg '#formId', {
    minWidth 100.px // resolves to 100px
p + div {
    border '1px solid black'
p | a { color red }         // | => ,
p >> a { color blue }       //>> => >
p * a { color blue }        // * => *
p - a { color blue }        // - => ~(tilde)
p ^ a { color blue }        // ^ =>  (space)

Not Allowed

The following is not-allowed/dynamic code:

table.my_class {         //<-- style-class
} {                  //<-- style-class
} div {              //<-- style-class
body p div {             //<-- No operators separating the elements


Since GrooCSS is just Groovy code, you should have IDE code completion (in IntelliJ IDEA for example click Ctrl+Space for code completion) when you stick to non-dynamic code.

Last updated: 31 July 2019