Fixed minor issues and enhancements

src/core/sheerka/Services/SheerkaEvaluateConcept.py

@@ -1,5 +1,5 @@
 from core.builtin_concepts import BuiltinConcepts
-from core.builtin_helpers import expect_one
+from core.builtin_helpers import expect_one, only_successful
 from core.concept import Concept, DoNotResolve, ConceptParts, InfiniteRecursionResolved
 
 CONCEPT_EVALUATION_STEPS = [
@@ -71,6 +71,11 @@ class SheerkaEvaluateConcept:
         :param logger:
         :return:
         """
+        def is_only_successful(r):
+#            return False
+            return context.sheerka.isinstance(r, BuiltinConcepts.RETURN_VALUE) and \
+            context.sheerka.isinstance(r.body, BuiltinConcepts.ONLY_SUCCESSFUL)
+
         steps = [BuiltinConcepts.BEFORE_PARSING, BuiltinConcepts.PARSING, BuiltinConcepts.AFTER_PARSING]
         for part_key in ConceptParts:
             if part_key in concept.compiled:
@@ -88,7 +93,8 @@ class SheerkaEvaluateConcept:
                     to_parse = self.sheerka.ret(context.who, True,
                                                 self.sheerka.new(BuiltinConcepts.USER_INPUT, body=source))
                     res = self.sheerka.execute(sub_context, to_parse, steps)
-                    concept.compiled[part_key] = res
+                    only_success = only_successful(sub_context, res)
+                    concept.compiled[part_key] = only_success.body.body if is_only_successful(only_success) else res
                     sub_context.add_values(return_values=res)
 
         for var_name, default_value in concept.metadata.variables:
@@ -106,7 +112,8 @@ class SheerkaEvaluateConcept:
                     to_parse = self.sheerka.ret(context.who, True,
                                                 self.sheerka.new(BuiltinConcepts.USER_INPUT, body=default_value))
                     res = self.sheerka.execute(context, to_parse, steps)
-                    concept.compiled[var_name] = res
+                    only_success = only_successful(sub_context, res)
+                    concept.compiled[var_name] = only_success.body.body if is_only_successful(only_success) else res
                     sub_context.add_values(return_values=res)
 
         # Updates the cache of concepts when possible
@@ -114,6 +121,7 @@ class SheerkaEvaluateConcept:
             self.sheerka.get_by_id(concept.id).compiled = concept.compiled
 
     def resolve(self, context, to_resolve, current_prop, current_concept, force_evaluation):
+
         if isinstance(to_resolve, DoNotResolve):
             return to_resolve.value