import data.list

open unsigned list

meta_definition e1  := expr.app (expr.app (expr.const "f" []) (expr.mk_var 1)) (expr.const "a" [])
meta_definition e1' := (expr.const "f" []) (expr.mk_var 1) (expr.const "a" [])

meta_definition tst : e1 = e1' :=
rfl

vm_eval e1

vm_eval expr.fold e1 (0:nat) (λ e d n, n+1)

meta_definition l1 := expr.lam "a" binder_info.default (expr.sort level.zero) (expr.mk_var 0)
meta_definition l2 := expr.lam "b" binder_info.default (expr.sort level.zero) (expr.mk_var 0)
meta_definition l3 := expr.lam "a" binder_info.default (expr.const "nat" []) (expr.mk_var 0)

vm_eval l1
vm_eval l2
vm_eval l3
vm_eval decidable.to_bool (l1 = l2)
vm_eval decidable.to_bool (l1 =ₐ l2)

vm_eval expr.lex_lt (expr.const "a" []) (expr.const "b" [])
vm_eval expr.lt (expr.const "a" []) (expr.const "b" [])

meta_definition v1 := (expr.const "f" []) (expr.mk_var 0) (expr.mk_var 1)

vm_eval v1
vm_eval expr.instantiate_var v1 (expr.const "a" [])

vm_eval expr.instantiate_vars v1 [expr.const "a" [], expr.const "b" []]

meta_definition fv1 := (expr.const "f" [])
                         (expr.local_const "a" "a" binder_info.default (expr.sort level.zero))
                         (expr.local_const "b" "b" binder_info.default (expr.sort level.zero))

vm_eval fv1

vm_eval expr.abstract_local (expr.abstract_local fv1 "a") "b"
vm_eval expr.abstract_locals fv1 ["a", "b"]
vm_eval expr.abstract_locals fv1 ["b", "a"]
vm_eval expr.lift_vars (expr.abstract_locals fv1 ["b", "a"]) 1 1
vm_eval expr.has_local fv1
vm_eval expr.has_var fv1
vm_eval expr.has_var (expr.abstract_locals fv1 ["b", "a"])

meta_definition foo : nat → expr
| 0     := expr.const "aa" [level.zero, level.succ level.zero]
| (n+1) := foo n

vm_eval match foo 10 with
| expr.const n ls := list.head (list.tail ls)
| _               := level.zero
end