structure myprod (A B : Type) :=
(fst : A) (snd : B)

variable p : myprod nat nat
variable f : nat → nat

#check p↣fst
#check p↣1
#check p↣2
#check p↣snd

#check p~>fst
#check p~>1
#check p~>2
#check p~>snd

#check f p↣1
#check p↣1 + p↣2

example (A B : Type) : A × B → B × A  :=
λ h, ⟨h↣2, h↣1⟩

example (A B : Type) : A × B → B × A  :=
λ h, ⟨h↣snd, h↣fst⟩

structure position (A B : Type) :=
(x : A) (y : B)

structure car :=
(pos : position nat nat) (cheap : bool)

#check λ c : car, c↣pos↣x

#check λ c : car, c↣fst

#check λ c : car, c↣0

#check λ c : car, c↣3

#check λ n : nat, n↣1

#check p.1
#check p.2
#check λ c : car, c.1.2