Using Kotlin WHEN clause for <, <=, >=, > comparisons -

i'm trying use when clause > or < comparison.

this doesn't compile. there way of using normal set of boolean operators (< <=, >= >) in comparison enable this?

val foo = 2  // doesn't compile when (foo) {     > 0 -> dosomethingwhenpositive()     0   -> dosomethingwhenzero()     < 0 -> dosomethingwhennegative() } 

i tried find unbounded range comparison, couldn't make work either? possible write unbounded range?

// trying unbounded range - doesn't compile when (foo) {     in 1.. -> dosomethingwhenpositive()     else -> dosomethingelse() } 

you can put whole expression in second part, ok seems unnecessary duplication. @ least compiles , works.

when {     foo > 0 -> dosomethingwhenpositive()     foo < 0 -> dosomethingwhennegative()     else -> dosomethingwhenzero() } 

but i'm not sure simpler if-else alternative have been doing years. like:

if ( foo > 0 ) {     dosomethingwhenpositive() } else if (foo < 0) {     dosomethingwhennegative() } else {     dosomethingwhenzero() } 

of course, real world problems more complex above, , when clause attractive doesn't work expect type of comparison.

even flexible language such kotlin doesn't have "elegant" / dry solution each , every case.

you can write like:

when (foo) {     in 0 .. int.max_value -> dosomethingwhenpositive()     0    -> dosomethingwhenzero()     else -> dosomethingwhennegative() } 

but depend on variable type.

i believe following form idiomatic in kotlin:

when {     foo > 0  -> dosomethingwhenpositive()     foo == 0 -> dosomethingwhenzero()     else     -> dosomethingwhennegative() } 

yeah... there (minimal) code duplication.

some languages (ruby?!) tried provide uber-elegant form case - there tradeoff: language becomes more complex , more difficult programmer know end-to-end.

my 2 cents...