Fixed first token recognition when creating bnf concepts

src/parsers/BnfNodeParser.py

@@ -391,10 +391,11 @@ class StrMatch(Match):
     Matches a literal
     """
 
-    def __init__(self, to_match, rule_name="", ignore_case=True):
+    def __init__(self, to_match, rule_name="", ignore_case=True, skip_whitespace=True):
         super(Match, self).__init__(rule_name=rule_name)
         self.to_match = to_match
         self.ignore_case = ignore_case
+        self.skip_white_space = skip_whitespace
 
     def __repr__(self):
         return self.add_rule_name_if_needed(f"'{self.to_match}'")
@@ -415,7 +416,7 @@ class StrMatch(Match):
 
         if m:
             node = TerminalNode(self, parser_helper.pos, parser_helper.pos, token.str_value)
-            parser_helper.next_token()
+            parser_helper.next_token(self.skip_white_space)
             return node
 
         return None
@@ -469,6 +470,8 @@ class BnfNodeFirstTokenVisitor(ParsingExpressionVisitor):
         return self.STOP
 
     def visit_StrMatch(self, pe):
+        if not pe.to_match:
+            return
         self.add_first_token(pe.to_match)
         return self.STOP
 
@@ -947,6 +950,9 @@ class BnfNodeParser(BaseNodeParser):
         :return:
         """
 
+        if not isinstance(parser_input, ParserInput):
+            return None
+
         context.log(f"Parsing '{parser_input}' with BnfNode", self.name)
         sheerka = context.sheerka