# Implementation of `==` and `hash` for `Derivable` objects.
#
# The implementations just call `==` and `hash` on `derive_to_map`.
#
# ~~~
# class A
#    auto_derive
#    super DeriveEqual
#    var an_int: Int
#    var a_string: String
# end
#
# var a = new A(5, "five")
# var b = new A(5, "five")
# var c = new A(6, "six")
# assert a == b
# assert a.hash == b.hash
# assert a != c
# ~~~
#
# Warning: the method may go in an infinite recursion if there is a circuit in
# the implementation of `==` or `hash`.
interface DeriveEqual
	super Derivable
	redef fun ==(other) do
		if not other isa Derivable then return false
		return derive_to_map == other.derive_to_map
	end
	redef fun hash do
		return derive_to_map.hash
	end
end