[Pyparsing] Bug report: setResultsName works inconsistently on Optional in Each

[Max R. <max...@gm...>]

It seems that Optional.setResultsName joined by Each does not behave
consistently with other ParserElements. For example:

>>> (Optional('foo')('one') & pp.Optional('bar')('two')).parseString('foo
bar')
(['foo', 'bar'], {})
>>> (Optional('bar')('two') & Optional('foo')('one')).parseString('foo bar')
(['foo', 'bar'], {'two': [('bar', 1)]})

A workaround is to name the Literals themselves instead of the Optionals:

>>> (Optional(Literal('bar')('two')) &
Optional(Literal('foo')('one'))).parseString('foo bar')
(['foo', 'bar'], {'two': [('bar', 1)], 'one': [('foo', 0)]})
>>> (Optional(Literal('foo')('one')) &
Optional(Literal('bar')('two'))).parseString('foo bar')
(['foo', 'bar'], {'two': [('bar', 1)], 'one': [('foo', 0)]})

The problem does not manifest when joining Optional objects with And:

>>> (Optional('foo')('one') + pp.Optional('bar')('two')).parseString('foo
bar')
(['foo', 'bar'], {'two': [('bar', 1)], 'one': [('foo', 0)]})

Thanks,
Max