How to set property in closure in Groovy, like in Gradle? - gradle

Question

Here is the Gradle documentation, which I don't understand:
idea {
//if you want parts of paths in resulting files (*.iml, etc.) to be replaced by variables (Files)
pathVariables GRADLE_HOME: file('~/cool-software/gradle')
module {
//if for some reason you want to add an extra sourceDirs
sourceDirs += file('some-extra-source-folder')
It sets idea.module.sourceDirs value.
How do I implement it in pure Groovy without Gradle? I want to know its underlying merchanism.

Answer 1

thanks #Steinar, I use following code fix:
def file(String p) {
new File(p)
}
class Idea {
class Module {
Set<File> excludeDirs = []
}
void module(Closure c) {
c.delegate = new Module()
c()
}
}
void idea(Closure c) {
c.delegate = new Idea()
c()
}
idea {
module {
excludeDirs += file("smth")
}
}

Answer 2

With your proposed solution #asullaherc you can't choose between calling idea { module and idea.module { ... so I would rather go for a different solution.
This is the base class for all of the closures you want to create for your case:
class SectionBase extends Closure<Object> {
SectionClosure() {
super(null)
}
Object doCall(final Closure inner) {
inner.delegate = this
inner()
}
}
And this would be an implementation ("Gradle style"):
class DependenciesSection extends SectionBase {
void compile(packageName) {
println "compile: $packageName"
}
void testCompile(packageName) {
println "testCompile: $packageName"
}
}
Now we make an instance:
def dependencies = new DependenciesSection()
And mess around with it a little:
// You can do it either this way...
dependencies {
compile 'com.my.package1'
compile 'com.my.package2'
testCompile 'com.my.package3'
}
// ...or also the other
dependencies.compile 'com.my.package4'
dependencies.testCompile 'com.my.package5'
The output would be:
compile: com.my.package1
compile: com.my.package2
testCompile: com.my.package3
compile: com.my.package4
testCompile: com.my.package5