Codegen/Rust: allow breaking up schema file

rust/schema/prelude.py

@@ -0,0 +1,41 @@
+from misc.codegen.lib.schemadefs import *
+
+@qltest.skip
+class Element:
+    pass
+
+
+@qltest.skip
+class Locatable(Element):
+    pass
+
+
+@qltest.skip
+class AstNode(Locatable):
+    pass
+
+
+@qltest.skip
+class Unextracted(Element):
+    """
+    The base class marking everything that was not properly extracted for some reason, such as:
+    * syntax errors
+    * insufficient context information
+    * yet unimplemented parts of the extractor
+    """
+    pass
+
+
+@qltest.skip
+class Missing(Unextracted):
+    """
+    The base class marking errors during parsing or resolution.
+    """
+
+
+@qltest.skip
+class Unimplemented(Unextracted):
+    """
+    The base class for unimplemented nodes. This is used to mark nodes that are not yet extracted.
+    """
+    pass