nac3artiq: add kernel only annotation demo

nac3artiq/demo/kernel_only_demo.py

@@ -0,0 +1,73 @@
+from min_artiq import *
+from numpy import int32
+
+@nac3
+class Base:
+    c: Kernel[int32]
+    def __init__(self):
+        self.c = 4
+        self.a = 3
+        self.a = 5
+
+@nac3
+class D:
+    da: KernelInvariant[int32]
+    def __init__(self):
+        self.da = 321
+
+@nac3
+class C:
+    ca: KernelInvariant[int32]
+    cb: KernelInvariant[D]
+    def __init__(self, d: D):
+        self.ca = 123
+        self.cb = d
+
+@nac3
+class A(Base):
+    core: KernelInvariant[Core]
+    led0: KernelInvariant[TTLOut]
+    led1: KernelInvariant[TTLOut]
+    d: Kernel[bool]
+    cc: Kernel[C]
+
+    def __init__(self, c):
+        super().__init__()
+        self.core = Core()
+        self.led0 = TTLOut(self.core, 18)
+        self.led1 = TTLOut(self.core, 19)
+        self.b = 3
+        self.d = False
+        self.cc = c
+    
+    @kernel
+    def run(self):
+        print_int32(self.cc.cb.da)
+
+
+if __name__ == '__main__':
+    d = D()
+    print(d.da)
+    c = C(d)
+    print(d.da)
+    print(c.cb.da)
+    
+    a = A(c)
+    print(a.a)
+    print(a.b)
+    # print(c.ca) # fail
+    # print(c.cb.da) # fail
+    
+    a.run()
+
+    # d = D() # redefine, ok
+    # c = C(d) # redefine, ok
+
+    # print(a.c) # fail
+    # a.c = 2 # fail
+    # a.d = 1 # fail
+    # a.cc = 1 # fail
+    # c.ca = 1 # fail
+    # c.cb = 1 # fail
+    # c.cb.da = 1 # fail
+    # d.da = 1 # fail