None now compiles to null instead of @null

Author: smartycope

pyndustric/compiler.py

@@ -1147,7 +1147,7 @@ def as_value(self, node, output: str = None):
             elif isinstance(node.value, (int, float)):
                 return str(node.value)
             elif node.value is None:
-                return "@null"
+                return "null"
             elif isinstance(node.value, str):
                 if (
                     len(str(node.value)) == 7 or len(str(node.value)) == 9

test_all.py

@@ -1161,7 +1161,7 @@ def test_complex_compare():
 @masm_test
 def test_None():
     """
-    set foo @null
+    set foo null
     """
     foo = None