oldnat.golden

--- opening "oldnat.ma" ---
--- scope checking ---
--- type checking ---
type  SNat : + Size -> Set
term  SNat.zero : .[s!ze : Size] -> .[i < s!ze] -> SNat s!ze
term  SNat.zero : .[i : Size] -> < SNat.zero i : SNat $i >
term  SNat.succ : .[s!ze : Size] -> .[i < s!ze] -> ^ SNat i -> SNat s!ze
term  SNat.succ : .[i : Size] -> ^(y1 : SNat i) -> < SNat.succ i y1 : SNat $i >
term  add : SNat # -> SNat # -> SNat #
{ add (SNat.zero [.#]) y = y
; add (SNat.succ [.#] x) y = SNat.succ [#] (add x y)
}
term  inc : .[i : Size] -> .[j : Size] -> SNat i -> SNat $i
{ inc [i] [j] x = SNat.succ [i] x
}
term  minus : .[i : Size] -> SNat i -> SNat # -> SNat i
{ minus [.$i] (SNat.zero [i]) y = SNat.zero [i]
; minus [i] x (SNat.zero [.#]) = x
; minus [.$i] (SNat.succ [i] x) (SNat.succ [.#] y) = minus [i] x y
}
term  test : SNat #
term  test = minus [#] (SNat.succ [#] (SNat.succ [#] (SNat.zero [#]))) (SNat.succ [#] (SNat.zero [#]))
term  div : .[i : Size] -> SNat i -> SNat # -> SNat i
{ div [.$i] (SNat.zero [i]) y = SNat.zero [i]
; div [.$i] (SNat.succ [i] x) y = SNat.succ [i] (div [i] (minus [i] x y) y)
}
type  Bool : Set
term  Bool.tt : < Bool.tt : Bool >
term  Bool.ff : < Bool.ff : Bool >
term  true : .[i : Size] -> SNat i -> Bool
{ true [.$i] (SNat.zero [i]) = Bool.tt
; true [.$i] (SNat.succ [i] x) = true [i] x
}
term  ok : .[Size] -> Bool
{ ok [i] = Bool.tt
}
--- evaluating ---
test has whnf (minus # (succ # (succ # (zero #))) (succ # (zero #)))
test evaluates to minus # (succ # (succ # (zero #))) (succ # (zero #))
--- closing "oldnat.ma" ---