linster / kotlinx.cli

Pure Kotlin implementation of a generic CLI parser.

kotlinx.cli

TODO download link

Pure Kotlin implementation of a generic command-line parser.

• Declarative: describe what your commands and parameters are
• Platform-agnostic: core library has no platform-specific dependencies and can be used in any Kotlin project
• Hackable: build extensions on top of it however you like

kotlinx.cli can be used to create user-friendly and flexible command-line interfaces for Kotlin/JVM, Kotlin/Native, and any other Kotlin console applications. Program defines what arguments are expected. kotlinx.cli will figure out how to parse those, reporting errors if the program arguments are invalid, and also generate help and usage messages as well.

Example

package kotlinx.cli.examples

import kotlinx.cli.*
import kotlin.system.exitProcess

fun main(args: Array<String>) {
    // Define command-line interface 
    val cli = CommandLineInterface("Example1")
    val integers by cli.positionalArgumentsList("N+", "Integers", minArgs = 1)
    val radix by cli.flagValueArgument("-r", "radix", "Input numbers radix", 10) { it.toInt() }
    val sum by cli.flagArgument("--sum", "Print sum")
    val max by cli.flagArgument("--max", "Print max")
    val min by cli.flagArgument("--min", "Print min")

    // Parse arguments or exit
    try {
        cli.parse(args)
    }
    catch (e: Exception) {
        exitProcess(1)
    }

    // Do something useful
    val ints = integers.map { it.toInt(radix) }
    println("Args: ${args.asList()}")
    println("Integers: $ints")
    if (sum) println("Sum: ${ints.sum()}")
    if (max) println("Max: ${ints.max()}")
    if (min) println("Min: ${ints.min()}")
}

Running this program without arguments produces the following output:

Usage: Example1 [-h] N+ [-r radix] [--sum] [--max] [--min] 

-h, --help                Prints help
N+                        Integers
-r radix                  Input numbers radix
--sum                     Print sum
--max                     Print max
--min                     Print min

Now, do some real work: run it with arguments -r 16 CAFE BABE DEAD BEEF --sum

Args: [-r, 16, CAFE, BABE, DEAD, BEEF, --sum]
Integers: [51966, 47806, 57005, 48879]
Sum: 205656