[基础软件理论与实践] 第三节作业实现（採石）

採石 2023-01-08 20:45:44

作业信息

课程信息：https://bbs.csdn.net/topics/608593392
第二节作业提交帖：https://bbs.csdn.net/topics/608988916

Complete the de Bruijn index based interpreter in natural semantics
Apply the de Bruijn index for extended lambda calculus (+ Let)

作业实现

任务1

在此稱術語：（de Bruijn index）爲德布朗數，（de Bruijn level）爲德布朗水平線。

我們先假定一種約定：

λn表示函式式項的參數有n個，即λ3.N式指代λ.λ.λ.N或λλλ.N。具體案例如：λ3.(0)(1)(2)，爲λ.λ.λ.(0)(1)(2)或λλλ.(0)(1)(2)。
假定處理的lambda式項均爲閉項，即其沒有自由變量。即λn.N，N當前層級的所有德布朗數均不大于n。

故解釋lambda式項時，首次進入後，將首先訪問函式項分支或調用項分支。

我們先假設初始lambda式項的形式爲λn.N。

我們在程式中，取n，並賦值給count變量；取N，並賦值給body變量。並對body進行演算，得果爲result。此時注意，程式裏後續使用了wrap_func函式把原函式項參數λn重新補充回result。即λn.(result)。


Fun(_) => {
  let (count, body) = extract(lambda)
  let result = calculus(body)
  wrap_func(count, result)
}

wrap_func函式的關鍵邏輯在于，演算結果result是否是函式項。若是函式項，則原函式德布朗參數會跟演算結果result的德布朗參數發生索引衝突。

假設演算結果result爲λm.M，則lambda等價于λn.(λm.M)。

具體案例如λ2.(λ2.(0)(1)(2)(3))。其n=2，m=2，λm.M爲λ2.(0)(1)(2)(3)，wrap_func(2, λ2.(0)(1)(2)(3))運行結果應當爲λ4.(2)(3)(0)(1)。

我們應注意到，輸入λ2.(λ2.M)，真正形態是λ(0).λ(1).(λ(0').λ(1').M)，運行結果形態爲λ(0).λ(1).λ(2).λ(3).M。

故程式邏輯，應將(0')爲(2)，將(1')爲(3)。代碼如下：

let rec wrap_func = (count, lambda) => {
  if count < 0 {
    assert false
  } else if count == 0 {
    lambda
  } else {
    switch lambda {
    | Fun(_) => {
        let (bcount, body) = extract(lambda)
        let t1 = direct_wrap_func(count + bcount, shift_one(body, 0))
        let t2 = direct_reduce(t1, Var(0), 2)
        let new_count = count - 1
        wrap_func(new_count, direct_unwrap_func(new_count, t2))
        /*
          性能優化版
          let (bcount, body) = extract(lambda)
          let t1 = direct_wrap_func(bcount, shift_one(body, 0))
          let t2 = Fun(reduce(t1, Var(0), count, count))
          let new_count = count - 1
          wrap_func(new_count, t2)
         */
      }

    | _ => direct_wrap_func(count, lambda)
    }
  }
}

若假設初始lambda式項的形式爲(X)(Y)。

又若X爲函式項λn.N，則應執行歸約(λn.N)[Y'/0]，其中Y'=shift(n, Y, 0)。

並對歸約結果，以當前層級爲基準，將所有德布朗數減一，把原函式項參數盡數補充回。

  let call_reduce = (lambda, va) => {
    let (count, body) = extract(lambda)
    let t = direct_reduce(body, shift(count, va, 0), 0)
    wrap_func(count - 1, unshift_one(t, 0))
  }

測試結果集：

常規測試
用例   (λ.0)(λ.0) ==> λ.0
輸入   (λ.0)(λ.0)
輸出   λ.0

用例   (λ.(0)(λ.0))(λ.0) ==> λ.0
輸入   (λ.(0)(λ.0))(λ.0)
輸出   λ.0

用例   (λ.0)(λλ.(0)(1)) ==> λλ.(0)(1)
輸入   (λ.0)(λλ.(0)(1))
輸出   λλ.(0)(1)

用例   (λλ.(1)(0))(λλ.(1)(0)) ==> λ.(0)(λλ.(1)(0))
輸入   (λλ.(1)(0))(λλ.(1)(0))
輸出   λ.(0)(λλ.(1)(0))

用例   (λλλ.(1)(2))(λλλ.(0)(1)(2)) ==> λλ.(0)(1)
輸入   (λλλ.(1)(2))(λλλ.(0)(1)(2))
輸出   λλ.(0)(1)

用例   (λλλ.(1)(2))(λλλ.(0)((1)(2))) ==> λλ.(0)(1)
輸入   (λλλ.(1)(2))(λλλ.(0)((1)(2)))
輸出   λλ.(0)(1)

用例   (λλλ.0)(λλλ.(0)((1)(2))) ==> λλλλλ.(2)((3)(4))
輸入   (λλλ.0)(λλλ.(0)((1)(2)))
輸出   λλλλλ.(2)((3)(4))

用例   λ.(λλ.(0)(1))(0) ==> λλ.(0)(1)
輸入   λ.(λλ.(0)(1))(0)
輸出   λλ.(0)(1)

用例   λλ.(λλλλ.(0)(1)(2)(3))(1)(0) ==> λλλλ.(1)(0)(2)(3)
輸入   λλ.(λλλλ.(0)(1)(2)(3))(1)(0)
輸出   λλλλ.(1)(0)(2)(3)

邱奇測試
用例   if_zero_then_else 0 ==> T
輸入   (λ.(0)(λλλ.2)(λλ.0))(λλ.1)
輸出   λλ.0

用例   if_zero_then_else 2 ==> F
輸入   (λ.(0)(λλλ.2)(λλ.0))(λλ.(0)((0)(1)))
輸出   λλ.1

用例   succ 3 ==> 4
輸入   (λλλ.(1)((0)(1)(2)))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)(1))))

用例   pred 4 ==> 3
輸入   (λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(λλ.(0)((0)((0)((0)(1)))))
輸出   λλ.(0)((0)((0)(1)))

用例   2 + 3 ==> 5
輸入   (λλλλ.(0)(2)((1)(2)(3)))(λλ.(0)((0)(1)))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)(1)))))

用例   5 - 2 ==> 3
輸入   (λλ.(1)(λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(0))(λλ.(0)((0)((0)((0)((0)(1))))))(λλ.(0)((0)(1)))
輸出   λλ.(0)((0)((0)(1)))

用例   multi1 4 × 3 ==> 12
輸入   (λλ.(λ.(0)(λλλ.2)(λλ.0))(0)(λλ.1)((0)(λ.(λλλλ.(0)(2)((1)(2)(3)))(0)(2))(λλ.1)))(λλ.(0)((0)((0)((0)(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)(1))))))))))))

用例   multi2 4 × 3 ==> 12
輸入   (λλλλ.(0)(λ.(2)(3)(0))(3))(λλ.(0)((0)((0)((0)(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)(1))))))))))))

用例   multi_wF 4 × 3 ==> 12
輸入   (λ.(0)(0))(λλλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.1)((λλλλ.(0)(2)((1)(2)(3)))(2)((λ.(0)(0))(0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1))(2))))(λλ.(0)((0)((0)((0)(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)(1))))))))))))

用例   multi_YF 4 × 3 ==> 12
輸入   (λ.(λ.(0)(0))(λ.(1)((λ.(0)(0))(0))))(λλλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.1)((λλλλ.(0)(2)((1)(2)(3)))(2)((0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1))(2))))(λλ.(0)((0)((0)((0)(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)((0)(1))))))))))))

用例   factorial_wF 3 ==> 6
輸入   (λ.(0)(0))(λλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.(0)(1))((λ.(0)(0))(λλλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.1)((λλλλ.(0)(2)((1)(2)(3)))(2)((λ.(0)(0))(0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1))(2))))(1)((λ.(0)(0))(0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)(1))))))

用例   factorial_YF 3 ==> 6
輸入   (λ.(λ.(0)(0))(λ.(1)((λ.(0)(0))(0))))(λλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.(0)(1))((λ.(λ.(0)(0))(λ.(1)((λ.(0)(0))(0))))(λλλ.(λ.(0)(λλλ.2)(λλ.0))(1)(λλ.1)((λλλλ.(0)(2)((1)(2)(3)))(2)((0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1))(2))))(1)((0)((λ.(λ.(0)(λλ.0))((0)(λ.(λλλ.(2)(0)(1))((λ.(0)(λλ.1))(0))((λλλ.(1)((0)(1)(2)))((λ.(0)(λλ.1))(0))))((λλλ.(2)(0)(1))(λλ.1)(λλ.1))))(1)))))(λλ.(0)((0)((0)(1))))
輸出   λλ.(0)((0)((0)((0)((0)((0)(1))))))

程式碼具體實現

open Belt
open Common

let roundString = str => "(" ++ str ++ ")"
let assoc = (x, env) => env->List.getAssoc(x, (a, b) => a == b)

type rec lambda /* 式項 */ =
  | Var(int) // 底項
  | Fun(lambda) // 函式項
  | App(lambda, lambda) // 調用項

let print_lambda = lambda => {
  let print_dot = is_parent_function =>
    if is_parent_function {
      "."
    } else {
      ""
    }
  let print_paren = (test, x) =>
    if test {
      roundString(x)
    } else {
      x
    }

  let rec go = (lambda, is_parent_function) => {
    switch lambda {
    | Fun(body) => "λ" ++ go(body, true)
    | Var(x) => print_dot(is_parent_function) ++ x->Int.toString
    | App(m, n) =>
      print_dot(is_parent_function) ++
      print_paren(
        switch m {
        | App(_, _) => false
        | _ => true
        },
        go(m, false),
      ) ++
      roundString(go(n, false))
    }
  }
  go(lambda, false)
}

let shift = (offset, lambda, depth) => {
  let rec go = (offset, lambda, depth) => {
    switch lambda {
    | App(m, n) => App(go(offset, m, depth), go(offset, n, depth))
    | Fun(body) => Fun(go(offset, body, depth + 1))
    | Var(index) =>
      if index >= depth {
        Var(index + offset)
      } else {
        lambda
      }
    }
  }
  go(offset, lambda, depth)
}

let shift_one = (lambda, depth) => shift(1, lambda, depth)
let unshift_one = (lambda, depth) => shift(-1, lambda, depth)

let rec reduce = (lambda, va, index, p_start_index) => {
  switch lambda {
  | App(m, n) =>
    App(reduce(m, va, index, p_start_index), reduce(n, va, index, p_start_index))
  | Fun(body) => Fun(reduce(body, shift_one(va, p_start_index), index + 1, p_start_index))

  | Var(n) =>
    if n == index {
      va
    } else {
      lambda
    }
  }
}

let direct_reduce = (lambda, va, p_start_index) => reduce(lambda, va, 0, p_start_index)

let rec extract = lambda =>
  switch lambda {
  | Fun(body) => {
      let (n, b) = extract(body)
      (1 + n, b)
    }

  | _ => (0, lambda)
  }

let rec wrap_func = (count, lambda) => {
  let rec direct_wrap_func = (count, body) => {
    if count == 0 {
      body
    } else if count < 0 {
      switch body {
      | Fun(child) => direct_wrap_func(count + 1, child)
      | _ => assert false
      }
    } else {
      direct_wrap_func(count - 1, Fun(body))
    }
  }
  let direct_unwrap_func = (count, body) => direct_wrap_func(-count, body)

  if count < 0 {
    assert false
  } else if count == 0 {
    lambda
  } else {
    switch lambda {
    | Fun(_) => {
        let (bcount, body) = extract(lambda)
        let t1 = direct_wrap_func(count + bcount, shift_one(body, 0))
        let t2 = direct_reduce(t1, Var(0), 2)
        let new_count = count - 1
        wrap_func(new_count, direct_unwrap_func(new_count, t2))
        /*
          let (bcount, body) = extract(lambda)
          let t1 = direct_wrap_func(bcount, shift_one(body, 0))
          let t2 = Fun(reduce(t1, Var(0), count, count))
          let new_count = count - 1
          wrap_func(new_count, t2)
         */
      }

    | _ => direct_wrap_func(count, lambda)
    }
  }
}

let rec calculus = lambda => {
  let call_reduce = (lambda, va) => {
    let (count, body) = extract(lambda)
    let t = direct_reduce(body, shift(count, va, 0), 0)
    wrap_func(count - 1, unshift_one(t, 0))
  }

  // 此式項內是否存在函式項。
  let rec has_unreduced_function = lambda =>
    switch lambda {
    | App(m, _) =>
      switch m {
      | Fun(_) => true
      | _ => has_unreduced_function(m)
      }
    | _ => false
    }

  let rec go = (lambda, depth) => {
    switch lambda {
    | Var(_) => lambda
    | Fun(_) => {
        let (count, body) = extract(lambda)
        wrap_func(count, calculus(body))
      }

    | App(m, n) =>
      switch m {
      | Fun(_) => {
          let t = call_reduce(m, n)
          if depth == 0 {
            calculus(t)
          } else {
            t
          }
        }

      | _ =>
        if has_unreduced_function(m) {
          // 若左式項尚存在未歸約的函式項，則先演算左式項。
          let ma = go(m, depth + 1)
          go(App(ma, n), depth)
        } else {
          // 因左式項全部歸約完畢，故開始演算右式項。
          App(m, calculus(n))
        }
      }
    }
  }
  go(lambda, 0)
}

type case_pair = {
  case: string,
  lambda: lambda,
}

let normal_lambdas = list{
  {
    case: "(λ.0)(λ.0) ==> λ.0",
    lambda: App(Fun(Var(0)), Fun(Var(0))),
  },
  {
    case: "(λ.(0)(λ.0))(λ.0) ==> λ.0",
    lambda: App(Fun(App(Var(0), Fun(Var(0)))), Fun(Var(0))),
  },
  {
    case: "(λ.0)(λλ.(0)(1)) ==> λλ.(0)(1)",
    lambda: App(Fun(Var(0)), Fun(Fun(App(Var(0), Var(1))))),
  },
  {
    case: "(λλ.(1)(0))(λλ.(1)(0)) ==> λ.(0)(λλ.(1)(0))",
    lambda: App(Fun(Fun(App(Var(1), Var(0)))), Fun(Fun(App(Var(1), Var(0))))),
  },
  {
    case: "(λλλ.(1)(2))(λλλ.(0)(1)(2)) ==> λλ.(0)(1)",
    lambda: App(
      Fun(Fun(Fun(App(Var(1), Var(2))))),
      Fun(Fun(Fun(App(App(Var(0), Var(1)), Var(2))))),
    ),
  },
  {
    case: "(λλλ.(1)(2))(λλλ.(0)((1)(2))) ==> λλ.(0)(1)",
    lambda: App(
      Fun(Fun(Fun(App(Var(1), Var(2))))),
      Fun(Fun(Fun(App(Var(0), App(Var(1), Var(2)))))),
    ),
  },
  {
    case: "(λλλ.0)(λλλ.(0)((1)(2))) ==> λλλλλ.(2)((3)(4))",
    lambda: App(Fun(Fun(Fun(Var(0)))), Fun(Fun(Fun(App(Var(0), App(Var(1), Var(2))))))),
  },
  {
    case: "λ.(λλ.(0)(1))(0) ==> λλ.(0)(1)",
    lambda: Fun(App(Fun(Fun(App(Var(0), Var(1)))), Var(0))),
  },
  {
    case: "λλ.(λλλλ.(0)(1)(2)(3))(1)(0) ==> λλλλ.(1)(0)(2)(3)",
    lambda: Fun(
      Fun(
        App(App(Fun(Fun(Fun(Fun(App(App(App(Var(0), Var(1)), Var(2)), Var(3)))))), Var(1)), Var(0)),
      ),
    ),
  },
}

// λλ.0
let b_true = Fun(Fun(Var(0)))
// λλ.1
let b_false = Fun(Fun(Var(1)))

// λλλ.(1)((0)(1)(2))
let succ = Fun(Fun(Fun(App(Var(1), App(App(Var(0), Var(1)), Var(2))))))

// λλ.1
let zero = Fun(Fun(Var(1)))
// λλ.(0)(1)
let one = calculus(App(succ, zero))
// λλ.(0)((0)(1))
let two = calculus(App(succ, one))
// λλ.(0)((0)((0)(1)))
let three = calculus(App(succ, two))
// λλ.(0)((0)((0)((0)(1))))
let four = calculus(App(succ, three))
// λλ.(0)((0)((0)((0)((0)(1)))))
let five = calculus(App(succ, four))

// λ.(0)(λ.(F))(T)
let if_zero_then_else = Fun(App(App(Var(0), wrap_func(1, b_false)), b_true))
// λλλ.(2)(0)(1)
let pair = Fun(Fun(Fun(App(App(Var(2), Var(0)), Var(1)))))
// λ.(0)(b_true)
let first = Fun(App(Var(0), b_true))
// λ.(0)(b_false)
let second = Fun(App(Var(0), b_false))

// λλλλ.(0)(2)((1)(2)(3))
let add = Fun(Fun(Fun(Fun(App(App(Var(0), Var(2)), App(App(Var(1), Var(2)), Var(3)))))))
// λ.(pair)(second (0))((succ)(second (0)))
let pred_it = Fun(App(App(pair, App(second, Var(0))), App(succ, App(second, Var(0)))))
// (pair)(zero)(zero)
let pair_zero = App(App(pair, zero), zero)
// λ.(first)((0)(pred_it)(pair_zero))
let pred = Fun(App(first, App(App(Var(0), pred_it), pair_zero)))
// λλ.(1)(pred)(0)
let minus = Fun(Fun(App(App(Var(1), pred), Var(0))))
// λλ.(if_zero_then_else)(0)(zero)((0)(λ.(add)(0)(2))(zero))
let multi1 = Fun(
  Fun(
    App(
      App(App(if_zero_then_else, Var(0)), zero),
      App(App(Var(0), Fun(App(App(add, Var(0)), Var(2)))), zero),
    ),
  ),
)
// λλλλ.(0)(λ.(2)(3)(0))(3)
let multi2 = Fun(Fun(Fun(Fun(App(App(Var(0), Fun(App(App(Var(2), Var(3)), Var(0)))), Var(3))))))

// λ.(0)(0)
let combinator_w = Fun(App(Var(0), Var(0)))
// λ.(combinator_w)(λ.(1)((combinator_w)(0)))
let combinator_Y = Fun(App(combinator_w, Fun(App(Var(1), App(combinator_w, Var(0))))))

// (combinator_w)(λλλ.(if_zero_then_else)(1)(zero)((add)(2)((combinator_w)(0)((pred)(1))(2))))
let multi_wF = App(
  combinator_w,
  Fun(
    Fun(
      Fun(
        App(
          App(App(if_zero_then_else, Var(1)), zero),
          App(App(add, Var(2)), App(App(App(combinator_w, Var(0)), App(pred, Var(1))), Var(2))),
        ),
      ),
    ),
  ),
)
// λλλ.(if_zero_then_else)(1)(zero)((add)(2)((0)((pred)(1))(2)))
let multi_F = Fun(
  Fun(
    Fun(
      App(
        App(App(if_zero_then_else, Var(1)), zero),
        App(App(add, Var(2)), App(App(Var(0), App(pred, Var(1))), Var(2))),
      ),
    ),
  ),
)
let multi_YF = App(combinator_Y, multi_F)

// (combinator_w)(λλ.(if_zero_then_else)(1)(one)((multi_wF)(1)((combinator_w)(0)((pred)(1)))))
let factorial_wF = App(
  combinator_w,
  Fun(
    Fun(
      App(
        App(App(if_zero_then_else, Var(1)), one),
        App(App(multi_wF, Var(1)), App(App(combinator_w, Var(0)), App(pred, Var(1)))),
      ),
    ),
  ),
)
// λλ.(if_zero_then_else)(1)(one)((multi_YF)(1)((0)((pred)(1))))
let factorial_F = Fun(
  Fun(
    App(
      App(App(if_zero_then_else, Var(1)), one),
      App(App(multi_YF, Var(1)), App(Var(0), App(pred, Var(1)))),
    ),
  ),
)
let factorial_YF = App(combinator_Y, factorial_F)

let church_lambdas = list{
  {
    case: "if_zero_then_else 0 ==> T",
    lambda: App(if_zero_then_else, zero),
  },
  {
    case: "if_zero_then_else 2 ==> F",
    lambda: App(if_zero_then_else, two),
  },
  {
    case: "succ 3 ==> 4",
    lambda: App(succ, three),
  },
  {
    case: "pred 4 ==> 3",
    lambda: App(pred, four),
  },
  {
    case: "2 + 3 ==> 5",
    lambda: App(App(add, two), three),
  },
  {
    case: "5 - 2 ==> 3",
    lambda: App(App(minus, five), two),
  },
  {
    case: "multi1 4 × 3 ==> 12",
    lambda: App(App(multi1, four), three),
  },
  {
    case: "multi2 4 × 3 ==> 12",
    lambda: App(App(multi2, four), three),
  },
  {
    case: "multi_wF 4 × 3 ==> 12",
    lambda: App(App(multi_wF, four), three),
  },
  {
    case: "multi_YF 4 × 3 ==> 12",
    lambda: App(App(multi_YF, four), three),
  },
  {
    case: "factorial_wF 3 ==> 6",
    lambda: App(factorial_wF, three),
  },
  {
    case: "factorial_YF 3 ==> 6",
    lambda: App(factorial_YF, three),
  },
}

let testSuit = pairs => {
  pairs->List.forEach(pair => {
    let {case, lambda} = pair
    Js.log("用例\t" ++ case)
    Js.log("輸入\t" ++ print_lambda(lambda))
    let reduction = calculus(lambda)
    Js.log("輸出\t" ++ print_lambda(reduction))
    Js.log("")
  })
}
Js.log("常規測試")
testSuit(normal_lambdas)
Js.log("邱奇測試")
testSuit(church_lambdas)

...全文