Defines parser errors

Author: Maxcode123

src/syntactes/parser/exception.py

@@ -0,0 +1,21 @@
+class ParserError(Exception): ...
+
+
+class UnexpectedTokenError(ParserError):
+    """
+    A token was received that does not map to an action. The stream of tokens
+    is syntactically invalid.
+    """
+
+    def __init__(self, received_token, expected_tokens):
+        self.received_token = received_token
+        self.expected_tokens = expected_tokens
+        msg = f"Received token: {received_token}; expected one of: {[str(e) for e in expected_tokens]}"
+        super().__init__(msg)
+
+
+class NotAcceptedError(ParserError):
+    """
+    The parser did not receive an accept action. The stream of tokens is
+    syntactically invalid.
+    """