Make enum conversion case-insensitive by default

[sschuberth]

I'd like to propose to make enum value conversion case-insensitive by default, because it's probably more convenient for the command line user to not care about casing, and the risk to accidentally refer to another enum value that just differs in case is rather low.

[sschuberth]

I was trying to work around this via option(...).convert { it.toUpperCase() }.enum<...>() to be able to use lower-case name for upper-case enum constants, but for some reason that does not work.

[sschuberth]

My work-around is to replace

.enum<OutputFormat>()

with

.choice(enumValues<OutputFormat>().associateBy { it.name }.toSortedMap(java.lang.String.CASE_INSENSITIVE_ORDER))

[sschuberth]

Or as a new extension function:

inline fun <reified T : Enum<T>> RawOption.enumCaseInsensitive(key: (T) -> String = { it.name }): NullableOption<T, T> {
    return choice(enumValues<T>().associateBy { key(it) }.toSortedMap(java.lang.String.CASE_INSENSITIVE_ORDER))
}

[ajalt]

That's a good idea. I decided to add an ignoreCase parameter to enum and choice, with value value defaulting to false for choice, and true for enum.

[sschuberth]

Even better, thanks a lot!