30 lines
650 B
Plaintext
30 lines
650 B
Plaintext
// Testing more interesting state types
|
|
contract Stack =
|
|
|
|
type stack('a) = list('a)
|
|
|
|
record state = { stack : stack(string),
|
|
size : int }
|
|
|
|
function init(ss : list(string)) = { stack = ss, size = length(ss) }
|
|
|
|
private function length(xs) =
|
|
switch(xs)
|
|
[] => 0
|
|
_ :: xs => length(xs) + 1
|
|
|
|
stateful function pop() : string =
|
|
switch(state.stack)
|
|
s :: ss =>
|
|
put(state{ stack = ss, size = state.size - 1 })
|
|
s
|
|
|
|
stateful function push(s) =
|
|
put(state{ stack = s :: state.stack, size = state.size + 1 })
|
|
state.size
|
|
|
|
function all() = state.stack
|
|
|
|
function size() = state.size
|
|
|