Scala curried function to execute any expression on condition-CodePudding

I'm trying to create a function that checks if a condition applies and runs any possible expression if it does, in case the condition doesn't apply this function returns a default value, I'm able to do it in the following way:

def executeOnCondition[T](condition: Boolean, default: T)(f: => T): T = if (condition) f else default

however I'd like this function to be curried so that it first takes the condition and default and only later executes the expression. imagined use:

val useLater = executeOnCondition(true, 3.14)
// do stuff
useLater { 3.14 * 2}

but when I try to create my curried function in the expected way:

def executeOnCondition[T](condition: Boolean, default: T) = (f: => T) => { if (condition) f else default }

I get this compilation error:

identifier expected but '=>' found.

I guess the problem is related to the use of generics, can anyone shed some light and maybe offer a work-around?

many thanks

CodePudding user response：

This is the proper syntax:

def executeOnCondition[T](condition: Boolean, default: T): (=> T) => T =
  block => if (condition) block else default

For some reason (bug?) you can't type => T as the type of a lambda input, even though the type is valid.