17:49 <FromGitter> <alex-kampa> So far I've done some tests and do not see any performance issues

18:51 <FromGitter> <wyhaines> It can starve other threads even when doing IO. The contexts under which Crystal effectively yields back to the scheduler so that something else can run are extremely limited.cd/

21:17 <FromGitter> <alex-kampa> ``` a = ["string", 13, 787.to_i64] ⏎ puts typeof(a[0]) #=> (Int32 | Int64 | String)``` ⏎ ⏎ Why does this not give me String [https://gitter.im/crystal-lang/crystal?at=60d101f5f862a72a30c71056]

21:18 <FromGitter> <tenebrousedge> because you're not using a Tuple

21:18 <FromGitter> <tenebrousedge> Arrays are variable sized, any element can be any of the types within the array

21:19 <FromGitter> <tenebrousedge> Tuples are fixed size and work like you are expecting with regards to types

21:19 <FromGitter> <alex-kampa> Sure, but every individual element has its own definite type at any given time.

21:19 <FromGitter> <Blacksmoke16> The compiler isn't able to prove that

21:20 <FromGitter> <tenebrousedge> that's true of any union type

21:22 <FromGitter> <alex-kampa> Ok so at runtime I want to do something if an element is a string, and something else if it is a number. Are you saying I need to convert the array into a tuple? Or is there another way?

21:22 <FromGitter> <tenebrousedge> use a case statement

21:23 <FromGitter> <tenebrousedge> and think about whether you really want an array with that union type in the first place

21:24 <FromGitter> <alex-kampa> @tenebrousedge - re case statement - ok but case what?

21:25 <FromGitter> <tenebrousedge> `case foo; when Int32 then do_stuff; when String then do_other_stuff`

21:27 <FromGitter> <Blacksmoke16> `a[0]` specifically

21:31 <FromGitter> <alex-kampa> Ok thanks that works - I was trying with typeof(a[0]) == "String" which didn't work.

21:38 <FromGitter> <alex-kampa> Anyway, the function I was actually looking for was ".is_a?" - had forgotten about it - but the case construction which uses is_a? implicitly is indeed more elegant

21:39 <FromGitter> <alex-kampa> Thanks again @tenebrousedge and @Blacksmoke16 !