Added empty string parser

evaluators/ConceptEvaluator.py

@@ -1,7 +1,10 @@
+from core.builtin_concepts import ParserResultConcept
 from core.concept import Concept, ConceptParts
 from evaluators.BaseEvaluator import OneReturnValueEvaluator
 import logging
 
+from parsers.BaseParser import BaseParser
+
 log = logging.getLogger(__name__)
 
 
@@ -11,8 +14,9 @@ class ConceptEvaluator(OneReturnValueEvaluator):
 
     def matches(self, context, return_value):
         return return_value.status and \
-            return_value.who == "Parsers:ConceptParser" and \
-            isinstance(return_value.value, Concept)
+               return_value.who.startswith(BaseParser.PREFIX) and \
+               isinstance(return_value.value, Concept) and \
+               not isinstance(return_value.value, ParserResultConcept)  # because there are specific evaluators
 
     def eval(self, context, return_value):
         sheerka = context.sheerka
@@ -27,9 +31,12 @@ class ConceptEvaluator(OneReturnValueEvaluator):
         # TODO; check pre
         # if pre is not true, return Concept with a false value
 
-        body = concept.codes[ConceptParts.BODY]
-        if body is None:
-            return None  # nothing to do
+        if ConceptParts.BODY in concept.codes:
+            body = concept.codes[ConceptParts.BODY]
+            if body is None:
+                return None  # nothing to do
 
-        return sheerka.ret(self.name, True, body.value, parents=[return_value])
+            return sheerka.ret(self.name, True, body.value, parents=[return_value])
 
+        else:
+            return sheerka.ret(self.name, True, concept, parents=[return_value])