Control_flow.fold

if sqrt x > 100 then
  print "it's too big"
else
  print "no"

for i <- [0..9] do
  print "i = %d" i
end

let x = &10 in
while *x > 0 do
  x := x - 1
end

when
| f x > 0 -> "too big"
| f x < 0 -> "too small"
| otherwise -> "good"
end

case result do
| Ok x -> print "It's ok, %s" x
| Error msg -> print ("Oh no: " ++ msg)
end