i don't suppose there's a way to say `when (foo) ...

# announcements

[sreich]

i don't suppose there's a way to say when (foo) { != 0 -> stuff(); else -> blah() }, while still using the var specifier, aka the (foo)

[bernhard]

sreich: I suppose your real usecase is much more complicated, but just swap the branches

[sreich]

Yeah there's a few more branches

[bernhard]

another hacky approach would be !in 0..0

[Andreas Sinz]

you just need to use var foo inside when?

[sreich]

Eh inside where?

[bernhard]

when (foo) {
   5 -> onlyWhenFive()
   foo != 0 -> stuff()
   else -> blah()
}

would still be possible
EDIT: okay, that's not valid, wasn't aware that you can't mix when expressions types... I thought it would be as mighty as in scala but there seems to be a quite big gap

[sreich]

And you can't just do !0 in the branch can you?

[bernhard]

nope, that's not possible either. there are no boolean expressions on the argument passed to when, just the kotlin keywords in and is

[bernhard]

either you use foo in every branch for boolean expressions (either all are boolean or all are the corresponding type of the when argument) or as a hack !in 0..0 where you create a range for [0]

[groostav]

just so we're clear, the fully verbosity is

when {
  foo == 5 -> onlyWhenFive()
  foo != 0 -> stuff()
  else -> blah()
}

so the thing we're trying to eliminate here is a couple of extra foo _expr_'s.

I could've sworn there were some issues for this but I cant find them now