Add a combination of adding/mapping arguments

Not sure whether it's something that should be part of the core of argparser but I came across a usecase which consists of multiple arguments (flags) being collected to obtain a set of switches (and allowing this set of switches to be validated).

I monkey patched it as this:

fun <E, T : MutableCollection<E>> ArgParser.addMapping(
        map: Map<String, E>,
        help: String,
        initialValue: T): ArgParser.Delegate<T> {
    val names = map.keys.toTypedArray()
    return option<T>(*names,
            errorName = map.keys.joinToString("|"),
            help = help,
            isRepeating = true) {
        val result = value.orElse { initialValue }
        result.add(map.getValue(optionName))
        result
    }.default(initialValue)
}

fun <E> ArgParser.addMapping(map: Map<String, E>, help: String): ArgParser.Delegate<MutableCollection<E>> =
        addMapping(map, help, mutableSetOf())

fun <E, T : MutableCollection<E>> ArgParser.addMapping(vararg pairs: Pair<String, E>, help: String, initialValue: T): ArgParser.Delegate<T> =
        addMapping(mapOf(*pairs), help, initialValue)

fun <E> ArgParser.addMapping(vararg pairs: Pair<String, E>, help: String): ArgParser.Delegate<MutableCollection<E>> =
        addMapping(mapOf(*pairs), help, mutableSetOf())

Here's an example of the usage:

    private val dumps: MutableCollection<DumpType> by commandParser.addMapping(
            "--heap" to DumpType.HEAP_DUMP,
            "--thread" to DumpType.THREAD_DUMP,
            "--database" to DumpType.THREAD_DUMP, help = "Type of dump to process (more than one type is allowed)")
            .addValidator { if (value.isEmpty()) throw InvalidArgumentException("At least one dump type must be selected") }

What do you think?

xenomachina / kotlin-argparser

Add a combination of adding/mapping arguments #31