Add a bconcat helper to the Parser class

src/parsy/__init__.py

@@ -171,6 +171,13 @@ def concat(self) -> Parser:
         """
         return self.map("".join)
 
+    def bconcat(self) -> Parser:
+        """
+        Returns a parser that concatenates together (as a bytestring) the previously
+        produced values.
+        """
+        return self.map(b"".join)
+
     def then(self, other: Parser) -> Parser:
         """
         Returns a parser which, if the initial parser succeeds, will

tests/test_parsy.py

@@ -162,6 +162,11 @@ def test_concat(self):
         self.assertEqual(parser.parse(""), "")
         self.assertEqual(parser.parse("abc"), "abc")
 
+    def test_bconcat(self):
+        parser = any_char.many().bconcat()
+        self.assertEqual(parser.parse(b""), b"")
+        self.assertEqual(parser.parse(b"abc"), b"abc")
+
     def test_generate(self):
         x = y = None