Implemented a first and basic version of a Rete rule engine

src/evaluators/DefRuleEvaluator.py

@@ -0,0 +1,56 @@
+import core.utils
+from core.builtin_concepts import BuiltinConcepts, ParserResultConcept
+from core.global_symbols import NotInit
+from core.rule import Rule, ACTION_TYPE_PRINT, ACTION_TYPE_EXEC
+from core.tokenizer import Keywords
+from evaluators.BaseEvaluator import OneReturnValueEvaluator
+from parsers.DefRuleParser import DefRuleNode, DefFormatRuleNode
+
+
+class DefRuleEvaluator(OneReturnValueEvaluator):
+    """
+    Used to store a new format rule
+    """
+    NAME = "DefRule"
+
+    def __init__(self):
+        super().__init__(self.NAME, [BuiltinConcepts.EVALUATION], 50)
+
+    def matches(self, context, return_value):
+        return return_value.status and \
+               isinstance(return_value.value, ParserResultConcept) and \
+               isinstance(return_value.value.value, DefRuleNode)
+
+    def eval(self, context, return_value):
+        """
+        Creates a Rule out of a DefRule and saves it in db
+        :param context:
+        :param return_value:
+        :return:
+        """
+
+        context.log("Adding a new rule", self.name)
+        rule_definition = return_value.value.value
+        sheerka = context.sheerka
+
+        name = None if rule_definition.name is NotInit else str(rule_definition.name)
+        predicate = core.utils.get_text_from_tokens(rule_definition.tokens[Keywords.WHEN][1:])
+        if isinstance(rule_definition, DefFormatRuleNode):
+            action_type = ACTION_TYPE_PRINT
+            action = core.utils.get_text_from_tokens(rule_definition.tokens[Keywords.PRINT][1:])
+            compiled_action = rule_definition.print
+        else:
+            action_type = ACTION_TYPE_EXEC
+            action = core.utils.get_text_from_tokens(rule_definition.tokens[Keywords.THEN][1:])
+            compiled_action = rule_definition.then
+
+        rule = Rule(action_type, name, predicate, action)
+        rule.compiled_predicates = rule_definition.when
+        rule.rete_disjunctions = rule_definition.rete
+        rule.compiled_action = compiled_action
+
+        ret = sheerka.create_new_rule(context, rule)
+        if not ret.status:
+            error_cause = sheerka.objvalue(ret.body)
+            context.log(f"Failed to add new rule '{rule}'. Reason: {error_cause}", self.name)
+        return sheerka.ret(self.name, ret.status, ret.value, parents=[return_value])