#91 2.1.0 regression involving nested delimitedLists

[Richard Otis]

The below minimal example hangs on pyparsing 2.1.0 but correctly parses on 2.0.7 and 2.0.3.

:::python
from pyparsing import delimitedList, Group, Optional, Suppress, alphanums, Word, ZeroOrMore

species_name = Word(alphanums+'+-*', min=1) + Optional(Suppress('%'))
# constituent arrays are colon-delimited
# each subarray can be comma- or space-delimited
constituent_array = Group(delimitedList(Group(delimitedList(species_name, ',') & 
                          ZeroOrMore(species_name)), ':'))

constituent_array.parseString("AL,FE")

[Paul McGuire]

I believes this works now in 2.1.8.