Pyparsing: JSON parser example not suitable for dicts list

Question

All,

I am trying to figure out how to handle a list of Dicts using pyparsing. I will return to the JSON parser example for best practices, but I found that it cannot handle the list of dicts!

Consider the following (this is an example of a JSON parser in stock, but with some deleted comments, and my test case instead of the standard one):

#!/usr/bin/env python2.7

from pyparsing import *

TRUE = Keyword("true").setParseAction( replaceWith(True) )
FALSE = Keyword("false").setParseAction( replaceWith(False) )
NULL = Keyword("null").setParseAction( replaceWith(None) )

jsonString = dblQuotedString.setParseAction( removeQuotes )
jsonNumber = Combine( Optional('-') + ( '0' | Word('123456789',nums) ) +
                    Optional( '.' + Word(nums) ) +
                    Optional( Word('eE',exact=1) + Word(nums+'+-',nums) ) )

jsonObject = Forward()
jsonValue = Forward()
jsonElements = delimitedList( jsonValue )
jsonArray = Group(Suppress('[') + Optional(jsonElements) + Suppress(']') )
jsonValue << ( jsonString | jsonNumber | Group(jsonObject)  | jsonArray | TRUE | FALSE | NULL )
memberDef = Group( jsonString + Suppress(':') + jsonValue )
jsonMembers = delimitedList( memberDef )
jsonObject << Dict( Suppress('{') + Optional(jsonMembers) + Suppress('}') )

jsonComment = cppStyleComment
jsonObject.ignore( jsonComment )

def convertNumbers(s,l,toks):
    n = toks[0]
    try:
        return int(n)
    except ValueError, ve:
        return float(n)

jsonNumber.setParseAction( convertNumbers )

if __name__ == "__main__":
    testdata = """
[ { "foo": "bar", "baz": "bar2" },
  { "foo": "bob", "baz": "fez" } ]
    """
    results = jsonValue.parseString(testdata)
    print "[0]:", results[0].dump()
    print "[1]:", results[1].dump()

This is valid JSON, but the pyparsing example does not work when trying to index into the second element of the expected array:

[0]: [[['foo', 'bar'], ['baz', 'bar2']], [['foo', 'bob'], ['baz', 'fez']]]
[1]:
Traceback (most recent call last):
  File "json2.py", line 42, in <module>
    print "[1]:", results[1].dump()
  File "/Library/Python/2.7/site-packages/pyparsing.py", line 317, in __getitem__
    return self.__toklist[i]
IndexError: list index out of range

Can someone help me determine what is wrong with this grammar?

EDIT . Fixed bug when parsing as a JSON object, not a value.

: : pyparsing: (erlang), Erlang, : (

Answer 1

, , - pyparsing , , , 1, dicts.

results = jsonValue.parseString(testdata)

results = jsonValue.parseString(testdata)[0]

, . , :

[0]: [['foo', 'bar'], ['baz', 'bar2']]
- baz: bar2
- foo: bar
[1]: [['foo', 'bob'], ['baz', 'fez']]
- baz: fez
- foo: bob

Answer 2

JSON, . :

jsonObject << Dict( Suppress('{') + Optional(jsonMembers) + Suppress('}') )

, {...}. [...]. , . :

{ "col1":{ "foo": "bar", "baz": "bar2" },
  "col2":{ "foo": "bob", "baz": "fez" } }

{ "data":[{ "foo": "bar", "baz": "bar2" },
          { "foo": "bob", "baz": "fez" }] }

. , ? !