Parsley fails to parse about parsley HOT 1 OPEN

This is not exactly a bug in Parsley, it just works different compared to PyMeta2. The meaning of the two string quotes (', ") should be described better in the documentation. Se below for a possible parser improvement as well.

In the test code, I try to match using " - ". The double quoted string is matched as a Token, and Parsley helpfully removes any whitespace that may come before it, effectively matching the pattern (' '* ' - '). This will of course never match. The correct pattern to use in this case is ' - ', which is matched against the exact string.

It works in PyMeta2 because " - " is not matched as a Token, but as a string. The PyMeta2 parser will parse ' - ' successfully, but it will never match, as it is handled by the exactly matcher, which only compares the first character on the input stream against the string. A pattern that works both in Parsley and PyMeta2 would have to be written as (' ' '-' ' '). (PyMeta2 has a token matcher as well, but I am unsure if it can be invoked.)

Maybe the Parsley grammar should fail to parse Tokens that start with whitespace. PyMeta2 on the other hand should fail on anything longer than a single character within single quotes.

from parsley.