Example:
val x = {k1=3, k2=false}
Ordering of keys does not matter.
You can nest records.
The type is: {k1:int, k2:bool}.
You use #k1 to access the value.
A tuple is just a record with keys 1, 2, etc. It is just syntactic sugar for a key. The type t1*t2*t3 is just shorthand for {1:t1, 2:t2, 3:t3}.