What is declaration?

The declaration (KoDeclaration) represents a code entity, a piece of Kotlin code. Every parsed Kotlin File (KoFileDeclaration) contains one or more declarations. The declaration can be a package (KoPackageDeclaration), property (KoPropertyDeclaration), annotation (KoAnnotationDeclaration), class (KoClassDeclaration), etc.

Consider this Kotlin code snippet file:

private const val logLevel = "debug"

open class Logger(val level: String) {
   fun log(message: String) {

The above snippet is represented by the KoFileDeclarationclass. It contains two declarations - property declaration (KoPropertyDeclaration) and class declaration (KoClassDeclaration). The Logger class declaration contains a single function declaration (KoFunctionDeclaration ):

Declarations mimic the Kotlin file structure. Konsts API provides a way to retrieve every element. To get all functions in all classes inside the file using .classes().functions() :

koFile // List<KoFile>
    .classes()  // List<KoClassDeclaration>
    .functions() // List<KoFunctionDeclaration>

To print declaration content use koDeclaration.print() method.

Declaration Properties

Each declaration contains a set of properties to facilitate filtering and verification eg. KoClass declaration has name, modifiers , annotations , declarations (containing KoFunction) etc. Here is how the name of the function can be retrieved.

val name = koFile // List<KoFileDeclaration>
    .classes()  // List<KoClassDeclaration>
    .functions() // List<KoFunctionDeclaration>
    .first() // KoFunctionDeclaration
    .name // String
println(name) // prints: log

Although it is possible to retrieve a property of a single declaration usually verification is performed on a collection of declarations matching certain criteria eg. methods annotated with specific annotations or classes residing within a single package. See the Declaration Filtering page.

Debugging Declaration Properties

Each declaration exposes a few additional properties to help with debugging:

  • text - provides declaration text eg. val property role = "Developer"

  • location - provides file path with file name, line, and column e.g. ~\Dev\IdeaProject\SampleApp\src\kotlin\com\sample\Logger:10:5

  • locationWithText - provides location together with the declaration text

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