For Gradle-style DSLs, you want IDE autocompletion and compile-time validation inside the closure. The `@DelegatesTo` annotation tells Groovy where to route undefined names. ```groovy import groovy.lang.DelegatesTo class HtmlBuilder { private List parts = [] void p(String text) { parts << "

${text}

" } void h1(String text) { parts << "

${text}

" } String build() { "${parts.join('')}" } } String html(@DelegatesTo(HtmlBuilder) Closure body) { def builder = new HtmlBuilder() body.delegate = builder body.resolveStrategy = Closure.DELEGATE_FIRST body.call() return builder.build() } def result = html { h1 "Welcome" p "This is a paragraph" p "Another paragraph" } println result ``` The `@DelegatesTo(HtmlBuilder)` tells: - IDE: provide autocomplete for HtmlBuilder methods inside the block - Static checker: verify these are valid methods - Runtime: actually delegates the calls (the real behavior) **Strategies** for inner DSLs: - `DELEGATE_FIRST` — delegate methods win - `OWNER_FIRST` (default) — calling code's methods win - `DELEGATE_ONLY` / `OWNER_ONLY` — exclusive **Type information for nested closures:** ```groovy String section(@DelegatesTo(SectionBuilder) Closure body) { ... } String page(@DelegatesTo(PageBuilder) Closure body) { def b = new PageBuilder() body.delegate = b body.call() b.build() } page { section { ... } // IDE knows this 'section' delegates to SectionBuilder } ``` **This is how Gradle's build files work:** ```groovy plugins { id 'java' // PluginsBlock methods } dependencies { implementation 'commons-io:commons-io:2.11' // DependencyHandler methods } ``` Each top-level closure delegates to a different builder type — IDE shows the right autocomplete based on which block you're in.

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