oop + generics in crystal

generics-and-oop.cr

abstract class QamAbstract
    def initialize()
        @forward–deps = [] of QamAbstract
    end
end

class Qam(T) < QamAbstract
    def initialize()
        super()
        @values = [] of T
    end
end

class FooTestQam(T) < Qam(T)
end

class Mul(A, B) < Qam(A)
    def initialize(a: Qam(A), b: Qam(B))
        super()
        @s1 = a
        @s2 = b
    end
end

def *(a: Qam(A), b: Qam(B))
    Mul.new(a, b)
end

class Qam(T) < QamAbstract
    def *(a)
        Mul.new(self, a)
    end
end

c–thing32 = FooTestQam(Float32).new
c–thing64 = FooTestQam(Float64).new
d–thing = Mul.new c–thing64, c–thing32

d–thing2 = c–thing32 * c–thing64
d–thing3 = d–thing * c–thing64