# from core.builtin_concepts import BuiltinConcepts
# from core.builtin_helpers import ensure_evaluated
# from core.concept import Concept, ConceptParts
# from evaluators.BaseEvaluator import OneReturnValueEvaluator
#
#
# class RetEvaluator(OneReturnValueEvaluator):
#     """
#     The evaluator transforms the concept, using the RET metadata value
#     """
#
#     NAME = "Ret"
#
#     def __init__(self):
#         super().__init__(self.NAME, [BuiltinConcepts.EVALUATION], 10)
#         self.enabled = False
#
#     def matches(self, context, return_value):
#         return return_value.status and \
#                isinstance(return_value.value, Concept) and \
#                return_value.value.metadata.ret is not None
#
#     def eval(self, context, return_value):
#         sheerka = context.sheerka
#         concept = return_value.value
#         context.log(f"Processing ret value for concept {concept}.", self.name)
#
#         if not concept.metadata.is_evaluated:
#             evaluated = ensure_evaluated(context, concept)
#             if evaluated.key != concept.key:
#                 context.log(f"Failed to evaluate concept '{concept}'")
#                 return None
#             ret = evaluated.get_value(ConceptParts.RET)
#         else:
#             ret = concept.get_value(ConceptParts.RET)
#
#         if isinstance(ret, Concept) and sheerka.is_known(ret):
#             return sheerka.ret(self.name, True, ret, parents=[return_value])
#
#         context.log(f"ret '{ret}' is not a concept!")
#         return None