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Facing an issue with a pipe in terminal regex.
Here is a subset of the grammar in question:
from lark import Lark
grammar = """
start: START
START: QUARTER [WS+ YEAR]
QUARTER: /q[1-4]/
WS: /\s/
YEAR: /(19[0-9]{2})|(20[0-3][0-9])/
"""
print(Lark(grammar).parse("q1 1923")) # works
print(Lark(grammar).parse("q1 2023")) # doesn't work
However, when we add parenthesis around the full YEAR regex, both the string examples get parsed correctly.
This works:
from lark import Lark
grammar = """
start: START
START: QUARTER [WS+ YEAR]
QUARTER: /q[1-4]/
WS: /\s/
YEAR: /((19[0-9]{2})|(20[0-3][0-9]))/
"""
print(Lark(grammar).parse("q1 1923")) # works
print(Lark(grammar).parse("q1 2023")) # works now
What am I missing here?