deriving Repr

Stream: general

[Qin Yuxuan]

structure Point where
  x : Float
  y : Float
deriving Repr

What does deriving Repr mean?

[Qin Yuxuan]

structure Point where
  x : Float
  y : Float
deriving Repr

What does deriving Repr mean?

[Henrik Böving]

"Figure out a Repr implementation automatically for this type given that all members of the type implement Repr themselves already"

[Bhakti Shah]

slightly tangential question: is there a difference between deriving Repr (right by the type definition) and deriving instance Repr for Type except for where you can place the statement? I've seen both but I'm not sure if there's a difference.

[Henrik Böving]

No, the main reason we have the second syntax is that you can for example have a type declared in some other module or even library and later still derive type class instances on it.