make_callable example for nmigen

make_callable.py

class Doubler(Elaboratable):
    def __init__(self):
        self.input = Signal(8)
        self.output = Signal(8)
        self.sync_output = Signal(8)

    def inputs(self):
        return [self.input]

    def outputs(self):
        return [self.output, self.sync_output]

    def elaborate(self, platform):
        m = Module()
        m.d.comb += self.output.eq(self.input << 1)
        m.d.sync += self.sync_output.eq(self.input << 1)
        return m

doubler = make_callable(Doubler())

assert doubler(1) == [2, 0]
assert doubler(2) == [4, 2]
assert doubler(2) == [4, 4]