I'm looking to do something pretty simple: I have a boolean expression, if it evaluates to `true`, I...

# arrow

[Marc Plano-Lesay]

I'm looking to do something pretty simple: I have a boolean expression, if it evaluates to true, I want to evaluate something and return it as a Some, otherwise I want to return a None. Here's a pretty trivial implementation that might be clearer:

fun <A> Option.Companion.cond(condition: Boolean, value: () -> A): Option<A> = if (condition) {
  value().some()
} else {
  None
}

Is there anything built-in that I'm missing?

[Cody Mikol]

I think conditionally only exists on Either, It seems like in this case it might be as concise to use a when

when(condition) {
 true -> value().some()
 false -> None
}

Otherwise you could just wrap that in an extension like you have

[Marc Plano-Lesay]

Thanks :-)

[Marc Plano-Lesay]

I find repeated calls a bit nicer with the extension, not having to deal with the false branches clears up quite a bit

[kartoffelsup]

Maybe takeIf could be an option as well:

value.takeIf { condition }.toOption()

[Marc Plano-Lesay]

Oh that's a nice one indeed

[Yeogai C]

I think this is what you're looking for?

https://arrow-kt.io/docs/next/apidocs/arrow-core/arrow.core/maybe.html

https://github.com/arrow-kt/arrow/blob/b608a054a5318fe57d7055c35bb64a5effb053b6/ar[…]libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Option.kt

public inline fun <A> Boolean.maybe(f: () -> A): Option<A> =
  if (this) {
    Some(f())
  } else {
    None
  }

[Marc Plano-Lesay]

Indeed! That's exactly what I'm after, thanks!