Which ones you want to use, and if you implement a new customization, itĬan be used with all of the existing functions without any repeatedīy default, option delegates return null if the option wasn’t provided Since the three types of customizations are orthogonal, you can choose You canĬhange this behavior with functions like default and multiple. if the option is not present, or is present more than once).īy default, the option delegate value is the null if the option is not given on the command line,Īnd will use the value of the last occurrence if the option is given more than once. How to handle all calls to the option (i.e.

Options take one value by default, but this can be changed withīuilt-in functions like pair and triple, or manually with

The number of values that the option requires.

The value type is String by default, but can be customized with built-in functions like There are three main types of behavior that can be customized default ( 0 to 0 ) val e : Pair by option (). Val a : String? by option () val b : Int? by option (). Suggesting Corrections for Mistyped Parameters Printing the Help Message When No Arguments Are Given Multiple Values from Environment Variablesįlag Option Values from Environment VariablesĬonfiguration Files and Environment Variables Why not a Kotlin library like kotlin-argparser or kotlinx.cli?ĭeduplicating option().multiple() into a unique set Developing Command Line Applications With Gradle

Kotlin null default value