Added concept 'isa' other_concept functionality

core/builtin_concepts.py

@@ -45,6 +45,7 @@ class BuiltinConcepts(Enum):
     ENUMERATION = "enum"  # represents a list or a set
     LIST = "list"  # represents a list
     CANNOT_RESOLVE_VALUE_ERROR = "value cannot be resolved"  # don't know how to find concept value
+    CONCEPT_ALREADY_IN_SET = "concept already in set"
 
     NODE = "node"
     GENERIC_NODE = "generic node"
@@ -68,6 +69,7 @@ BuiltinErrors = [str(e) for e in {
     BuiltinConcepts.CONCEPT_ALREADY_DEFINED,
     BuiltinConcepts.CONCEPT_EVAL_ERROR,
     BuiltinConcepts.CANNOT_RESOLVE_VALUE_ERROR,
+    BuiltinConcepts.CONCEPT_ALREADY_IN_SET,
 }]
 
 """
@@ -320,3 +322,24 @@ class ListConcept(Concept):
 
     def __contains__(self, item):
         return item in self.body
+
+
+class ConceptAlreadyInSet(Concept):
+    def __init__(self, concept=None, concept_set=None):
+        super().__init__(BuiltinConcepts.CONCEPT_ALREADY_IN_SET,
+                         True,
+                         False,
+                         BuiltinConcepts.CONCEPT_ALREADY_IN_SET,
+                         concept)
+        self.set_prop("concept_set", concept_set)
+
+    def __repr__(self):
+        return f"ConceptAlreadyInSet(concept={self.concept}, concept_set={self.concept_set})"
+
+    @property
+    def concept(self):
+        return self.body
+
+    @property
+    def concept_set(self):
+        return self.props["concept_set"].value