@@nameguard not honored in simple grammar

[dvdrndlph]

I am puzzled by this behavior:

from pprint import pprint
from tatsu import parse

GRAMMAR = """
sequence = {fingering}+ ;
fingering = '1' | '2' | '3' | '4' | '5' | 'x' ;
"""

test = "22"
ast = parse(GRAMMAR, test)
pprint(ast)  # Prints ['2', '2']

test = "xx"
ast = parse(GRAMMAR, test)
pprint(ast)  # tatsu.exceptions.FailedParse: (1:1) no available options :

Setting the grammar to the following works as expected:

GRAMMAR = """
sequence = {fingering}+ ;
fingering = /[1-5x]/ ; 
"""

Am I missing something?

[Victorious3]

You either have to tell the parser what rule to start with or name it "start".
I'm not sure why the other one works in the first place. There's also $ to specify the end of input, I'd add that to your starting rule.

[apalala]

These are questions better asked on StackOverflow.

You probably need to check interactions with @@nameguard, which is turned on by default.

[apalala]

Confirmed that the results is unexpected even with @@nameguard :: False

[dvdrndlph]

Thanks for the quick turnaround. I learned a lot.