Source file: opt.fut

Option types

Futhark does not predefine an option type, but we can define one ourselves.

type opt 'a = #some a | #none

It can be used for example to define a safe indexing function.

def index_maybe [n] 't (x: [n]t) (i: i64) : opt t =
  if i >= 0 && i < n then #some x[i] else #none

See also