Implemented a first and basic version of a Rete rule engine

src/evaluators/PythonEvaluator.py

@@ -36,12 +36,16 @@ def inject_context(context):
 
 
 class Expando:
-    def __init__(self, bag):
+    def __init__(self, name, bag):
+        self.__name = name
         for k, v in bag.items():
             setattr(self, k, v)
 
     def __repr__(self):
-        return f"{dir(self)}"
+        return f"{vars(self)}"
+
+    def get_name(self):
+        return self.__name
 
 
 @dataclass
@@ -89,12 +93,12 @@ class PythonEvaluator(OneReturnValueEvaluator):
 
     def eval(self, context, return_value):
         sheerka = context.sheerka
-        node = get_python_node(return_value.value.value)
+        node = return_value.value.value.get_python_node()
 
         debugger = context.get_debugger(PythonEvaluator.NAME, "eval")
         debugger.debug_entering(node=node)
         exception_debugger = context.get_debugger("Exceptions", PythonEvaluator.NAME + ".eval")
-        get_trace_back = context.debug_enabled or exception_debugger.is_enabled()
+        get_trace_back = exception_debugger.is_enabled()
 
         context.log(f"Evaluating python node {node}.", self.name)
 
@@ -179,8 +183,6 @@ class PythonEvaluator(OneReturnValueEvaluator):
         """
         unreferenced_names_visitor = UnreferencedNamesVisitor(context)
         names = unreferenced_names_visitor.get_names(node.ast_)
-        if context.debug_enabled:
-            context.debug(self.NAME, "eval", "names", names)
         return self.get_globals_by_names(context, names, node, expression_only)
 
     def get_sheerka_method(self, context, name, expression_only):
@@ -200,6 +202,7 @@ class PythonEvaluator(OneReturnValueEvaluator):
         my_globals = {
             "Concept": core.concept.Concept,
             "BuiltinConcepts": core.builtin_concepts.BuiltinConcepts,
+            "Expando": Expando,
             "ExecutionContext": ExecutionContext,
             "in_context": context.in_context,
         }
@@ -218,14 +221,14 @@ class PythonEvaluator(OneReturnValueEvaluator):
                 continue
 
             # support reference to sheerka
-            if name == "sheerka":
+            if name.lower() == "sheerka":
                 bag = {}
                 visitor = NamesWithAttributesVisitor()
                 for sequence in visitor.get_sequences(node.ast_, "sheerka"):
                     if (len(sequence) > 1 and
                         (method := self.get_sheerka_method(context, sequence[1], expression_only)) is not None):
                         bag[sequence[1]] = method
-                my_globals["sheerka"] = Expando(bag)
+                my_globals[name] = Expando("sheerka", bag)
                 continue
 
             # search in local variables. To remove when local variables will be merged with memory