lean2/tests/lua/ind1.lua

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local env = environment()
local l = mk_param_univ("l")
local A = Const("A")
local U_l = mk_sort(l)
local U_l1 = mk_sort(max_univ(l, 1)) -- Make sure U_l1 is not Bool/Prop
local list_l = Const("list", {l}) -- list.{l}
local Nat = Const("nat")
local vec_l = Const("vec", {l}) -- vec.{l}
local zero = Const("zero")
local succ = Const("succ")
local forest_l = Const("forest", {l})
local tree_l = Const("tree", {l})
local n = Const("n")
env = env:add_global_level("u")
env = env:add_global_level("v")
local u = global_univ("u")
local v = global_univ("v")
function display_type(env, t)
print(tostring(t) .. " : " .. tostring(type_checker(env):check(t)))
end
env = add_inductive(env,
"nat", Type,
"zero", Nat,
"succ", mk_arrow(Nat, Nat))
-- In the following inductive datatype, {l} is the list of universe level parameters.
-- 1 is the number of parameters.
-- The Boolean true in {A, U_l, true} is marking that this argument is implicit.
env = add_inductive(env,
"list", {l}, 1, Pi(A, U_l, U_l1),
"nil", Pi({{A, U_l, true}}, list_l(A)),
"cons", Pi({{A, U_l, true}}, mk_arrow(A, list_l(A), list_l(A))))
env = add_inductive(env,
"vec", {l}, 1, Pi({{A, U_l}, {n, Nat}}, U_l1),
"vnil", Pi({{A, U_l, true}}, vec_l(A, zero)),
"vcons", Pi({{A, U_l, true}, {n, Nat, true}}, mk_arrow(A, vec_l(A, n), vec_l(A, succ(n)))))
local And = Const("and")
local Or = Const("or")
local B = Const("B")
-- Datatype without introduction rules (aka constructors). It is a uninhabited type.
env = add_inductive(env, "false", Bool)
-- Datatype with a single constructor.
env = add_inductive(env, "true", Bool, "trivial", Const("true"))
env = add_inductive(env,
"and", 2, Pi({{A, Bool}, {B, Bool}}, Bool),
"and_intro", Pi({{A, Bool, true}, {B, Bool, true}}, mk_arrow(A, B, And(A, B))))
env = add_inductive(env,
"or", 2, Pi({{A, Bool}, {B, Bool}}, Bool),
"or_intro_left", Pi({{A, Bool, true}, {B, Bool, true}}, mk_arrow(A, Or(A, B))),
"or_intro_right", Pi({{A, Bool, true}, {B, Bool, true}}, mk_arrow(B, Or(A, B))))
local P = Const("P")
local a = Const("a")
local exists_l = Const("exists", {l})
env = add_inductive(env,
"exists", {l}, 2, Pi({{A, U_l}, {P, mk_arrow(A, Bool)}}, Bool),
"exists_intro", Pi({{A, U_l, true}, {P, mk_arrow(A, Bool), true}, {a, A}}, mk_arrow(P(a), exists_l(A, P))))
env = add_inductive(env, {l}, 1,
{"tree", Pi(A, U_l, U_l1),
"node", Pi({{A, U_l, true}}, mk_arrow(A, forest_l(A), tree_l(A)))
},
{"forest", Pi(A, U_l, U_l1),
"emptyf", Pi({{A, U_l, true}}, forest_l(A)),
"consf", Pi({{A, U_l, true}}, mk_arrow(tree_l(A), forest_l(A), forest_l(A)))})
local tc = type_checker(env)
display_type(env, Const("forest", {mk_level_zero()}))
display_type(env, Const("vcons", {mk_level_zero()}))
display_type(env, Const("consf", {mk_level_zero()}))
display_type(env, Const("forest_rec", {v, u}))
display_type(env, Const("nat_rec", {v}))
display_type(env, Const("or_rec"))
local Even = Const("Even")
local Odd = Const("Odd")
local b = Const("b")
env = add_inductive(env, {},
{"Even", mk_arrow(Nat, Bool),
"zero_is_even", Even(zero),
"succ_odd", Pi(b, Nat, mk_arrow(Odd(b), Even(succ(b))))},
{"Odd", mk_arrow(Nat, Bool),
"succ_even", Pi(b, Nat, mk_arrow(Even(b), Odd(succ(b))))})
local flist_l = Const("flist", {l})
env = add_inductive(env,
"flist", {l}, 1, Pi(A, U_l, U_l1),
"fnil", Pi({{A, U_l, true}}, flist_l(A)),
"fcons", Pi({{A, U_l, true}}, mk_arrow(mk_arrow(Nat, A), mk_arrow(Nat, Bool, flist_l(A)), flist_l(A))))
local eq_l = Const("eq", {l})
env = add_inductive(env,
"eq", {l}, 2, Pi({{A, U_l}, {a, A}, {b, A}}, Bool),
"refl", Pi({{A, U_l}, {a, A}}, eq_l(A, a, a)))
display_type(env, Const("eq_rec", {v, u}))
display_type(env, Const("exists_rec", {v, u}))
display_type(env, Const("list_rec", {v, u}))
display_type(env, Const("Even_rec"))
display_type(env, Const("Odd_rec"))
display_type(env, Const("and_rec", {v}))
display_type(env, Const("vec_rec", {v, u}))
display_type(env, Const("flist_rec", {v, u}))
local U_1 = mk_level_one()
local n = Const("n")
local c = Const("c")
local nat_rec1 = Const("nat_rec", {U_1})
local add = Fun({{a, Nat}, {b, Nat}}, nat_rec1(mk_lambda("_", Nat, Nat), b, Fun({{n, Nat}, {c, Nat}}, succ(c)), a))
display_type(env, add)
local tc = type_checker(env)
assert(tc:is_def_eq(add(succ(succ(zero)), succ(zero)),
succ(succ(succ(zero)))))
assert(tc:is_def_eq(add(succ(succ(succ(zero))), succ(succ(zero))),
succ(succ(succ(succ(succ(zero)))))))
local list_nat = Const("list", {U_1})(Nat)
local list_nat_rec1 = Const("list_rec", {U_1, U_1})(Nat)
display_type(env, list_nat_rec1)
local h = Const("h")
local t = Const("t")
local v = Const("v")
local l = Const("l")
local length = Fun(l, list_nat, list_nat_rec1(mk_lambda("_", list_nat, Nat), zero, Fun({{h, Nat}, {t, list_nat}, {v, Nat}}, succ(v)), l))
local nil_nat = Const("nil", {U_1})(Nat)
local cons_nat = Const("cons", {U_1})(Nat)
print(tc:whnf(length(nil_nat)))
assert(tc:is_def_eq(length(nil_nat), zero))
assert(tc:is_def_eq(length(cons_nat(zero, nil_nat)), succ(zero)))
assert(tc:is_def_eq(length(cons_nat(zero, cons_nat(zero, nil_nat))), succ(succ(zero))))