Using QuotedString in pyparsing

Question

I'm having conceptual difficulty in understanding how to build a pyparsing parser. The steps are: 1) build a parser by combining subclasses of ParserElement, and 2) use the parser to parse a string.

The following example works fine:

from pyparsing import Word, Literal, alphas, alphanums, delimitedList, QuotedString

name = Word(alphas+"_", alphanums+"_")
field = name
fieldlist = delimitedList(field)
doc = Literal('<Begin>') + fieldlist + Literal('**End**')

dstring = '<Begin>abc,de34,f_o_o**End**'
print(doc.parseString(dstring))

yielding the expected sequence of tokens:

['<Begin>', 'abc', 'de34', 'f_o_o', '**End**']

But (for example), the class QuotedString does not take a ParserElement as an argument so it can't be used to build up a parser. I'd expect to use it in the above example like:

name = Word(alphas+"_", alphanums+"_")
field = QuotedString(name)     ### Wrong: doesn't allow "name" as an argument
fieldlist = delimitedList(field)

to parse a document of the form:

dstring = '<Begin>"abc", "de34", "f_o_o"**End**'

But since it can't be used that way, what is the proper syntax for including QuotedString in the construction of a parser for a list of quoted strings?

======== Edit ============

See answer below ...

Answer 1

QuotedString cannot be used for this task. But an OR function can achieve the same effect - allowing different forms of quotes while preserving the ability to parse the validity of the string contained within the quotes. The following code does that:

from pyparsing import Word, Literal, alphas, alphanums, delimitedList
from pyparsing import Group, QuotedString, ParseException, Suppress

name = Word(alphas+"_", alphanums+"_")
field = Suppress('"') + name + Suppress('"') ^ \    # double quote
        Suppress("'") + name + Suppress("'") ^ \    # single quote
        Suppress("<") + name + Suppress(">") ^ \    # html tag
        Suppress("{{")+ name + Suppress("}}")       # django template variable
fieldlist = Group(delimitedList(field))
doc = Literal('<Begin>') + fieldlist + Literal('**End**')

dstring = [
    '<Begin>"abc","de34","f_o_o"**End**',      # Good
    '<Begin><abc>,{{de34}},\'f_o_o\'**End**',  # Good
    '<Begin>"abc",\'de34","f_o_o\'**End**',    # Bad - mismatched quotes
    '<Begin>"abc","de34","f_o#o"**End**',      # Bad - invalid identifier
]

for ds in dstring:
    print(ds)
    try:
        print('  ', doc.parseString(ds))
    except ParseException as err:
        print(" "*(err.column-1) + "^")
        print(err)

This produces the desired output, accepting the two good test strings and rejecting the two bad ones:

<Begin>"abc","de34","f_o_o"**End**
   ['<Begin>', ['abc', 'de34', 'f_o_o'], '**End**']
<Begin><abc>,{{de34}},'f_o_o'**End**
   ['<Begin>', ['abc', 'de34', 'f_o_o'], '**End**']
<Begin>"abc",'de34","f_o_o'**End**
            ^
Expected "**End**" (at char 12), (line:1, col:13)
<Begin>"abc","de34","f_o#o"**End**
                   ^
Expected "**End**" (at char 19), (line:1, col:20)

Thank you Paul for all the help and for producing such a cool package.