The task is to read a configuration file in standard configuration file format,
and set variables accordingly.

For this task, we have a configuration file as follows:

# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.

# This is the fullname parameter
FULLNAME Foo Barber

# This is a favourite fruit
FAVOURITEFRUIT banana

# This is a boolean that should be set
NEEDSPEELING

# This boolean is commented out
; SEEDSREMOVED

# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.

# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser. 

# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.

OTHERFAMILY Rhu Barber, Harry Barber



For the task we need to set four variables according to the configuration entries as follows:

fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false


We also have an option that contains multiple parameters. These may be stored in an array.

 otherfamily(1) = Rhu Barber
 otherfamily(2) = Harry Barber


Related tasks
 Update a configuration file


import java.nio.charset.StandardCharsets
import java.nio.file.Files
import java.nio.file.Paths
 
data class Configuration(val map: Map<String, Any?>) {
    val fullName: String by map
    val favoriteFruit: String by map
    val needsPeeling: Boolean by map
    val otherFamily: List<String> by map
}
 
fun main(args: Array<String>) {
    val lines = Files.readAllLines(Paths.get("src/configuration.txt"), StandardCharsets.UTF_8)
    val keyValuePairs = lines.map{ it.trim() }
            .filterNot { it.isEmpty() }
            .filterNot(::commentedOut)
            .map(::toKeyValuePair)
 
    val configurationMap = hashMapOf<String, Any>("needsPeeling" to false)
    for (pair in keyValuePairs) {
        val (key, value) = pair
        when (key) {
            "FULLNAME"       -> configurationMap.put("fullName", value)
            "FAVOURITEFRUIT" -> configurationMap.put("favoriteFruit", value)
            "NEEDSPEELING"   -> configurationMap.put("needsPeeling", true)
            "OTHERFAMILY"    -> configurationMap.put("otherFamily", value.split(" , ").map { it.trim() })
            else             -> println("Encountered unexpected key $key=$value")
        }
    }
    println(Configuration(configurationMap))
}
 
private fun commentedOut(line: String) = line.startsWith("#") || line.startsWith(";")
 
private fun toKeyValuePair(line: String) = line.split(Regex(" "), 2).let {
    Pair(it[0], if (it.size == 1) "" else it[1])
}