What is the $end token?

[Zelatrix]

I have used the RPLY library to write a compiler and one error seems to be cropping up the most. That error is the following:

ValueError: Token('$end', '$end')

What is the $end token and how can I fix the error?

Check this issue #80 you might find a way to fix it.

[chriszumberge]

@Zelatrix
if you use rply.lexer.Lexer.lex(str) method to get your tokens, it's returning a rply.lexer.LexerStream object.
If you then do anything with that object, such as enumerating it, it runs the stream to its end.

Then, as I understand it, if you try to use the tokens LexerStream object in the parser, it's just getting the $end token- creating your error.

The solution for you might be to just not use the tokens in any way before passing them to the parser, or, resetting the stream if that's possible (I have not tried)

[DustinEwan]

This is an old, old issue, but @chriszumberge nailed it. If you print the tokens before trying to parse them, the iterator will be at the end already. Then when the parser tries to parse the token stream, it sees an empty stream.

You can either simply not print the tokens or you could lex the input again to get a fresh iterator.