lean4-htt/tests/lean/run/doLetElse.lean
2022-02-03 15:55:03 -08:00

12 lines
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Text

def foo (x? : Option Nat) : IO Nat := do
let some x := x? | return 0
IO.println s!"x: {x}"
return x
def test (input : Option Nat) (expected : Nat) : IO Unit := do
assert! (← foo input) == expected
#eval test (some 10) 10
#eval test none 0
#eval test (some 1) 1