1# parseListString.py 2# 3# Copyright, 2006, by Paul McGuire 4# 5 6from pyparsing import * 7 8# first pass 9lbrack = Literal("[") 10rbrack = Literal("]") 11integer = Word(nums).setName("integer") 12real = Combine(Optional(oneOf("+ -")) + Word(nums) + "." + 13 Optional(Word(nums))).setName("real") 14 15listItem = real | integer | quotedString 16 17listStr = lbrack + delimitedList(listItem) + rbrack 18 19test = "['a', 100, 3.14]" 20 21print(listStr.parseString(test)) 22 23 24# second pass, cleanup and add converters 25lbrack = Literal("[").suppress() 26rbrack = Literal("]").suppress() 27cvtInt = lambda s,l,toks: int(toks[0]) 28integer = Word(nums).setName("integer").setParseAction( cvtInt ) 29cvtReal = lambda s,l,toks: float(toks[0]) 30real = Regex(r'[+-]?\d+\.\d*').setName("floating-point number").setParseAction( cvtReal ) 31listItem = real | integer | quotedString.setParseAction( removeQuotes ) 32 33listStr = lbrack + delimitedList(listItem) + rbrack 34 35test = "['a', 100, 3.14]" 36 37print(listStr.parseString(test)) 38 39# third pass, add nested list support, and tuples, too! 40cvtInt = lambda s,l,toks: int(toks[0]) 41cvtReal = lambda s,l,toks: float(toks[0]) 42 43lbrack = Literal("[").suppress() 44rbrack = Literal("]").suppress() 45integer = Word(nums).setName("integer").setParseAction( cvtInt ) 46real = Regex(r'[+-]?\d+\.\d*').setName("floating-point number").setParseAction( cvtReal ) 47tupleStr = Forward() 48listStr = Forward() 49listItem = real | integer | quotedString.setParseAction(removeQuotes) | Group(listStr) | tupleStr 50tupleStr << ( Suppress("(") + delimitedList(listItem) + Optional(Suppress(",")) + Suppress(")") ) 51tupleStr.setParseAction( lambda t:tuple(t.asList()) ) 52listStr << lbrack + delimitedList(listItem) + Optional(Suppress(",")) + rbrack 53 54test = "['a', 100, ('A', [101,102]), 3.14, [ +2.718, 'xyzzy', -1.414] ]" 55print(listStr.parseString(test)) 56 57# fourth pass, add parsing of dicts 58cvtInt = lambda s,l,toks: int(toks[0]) 59cvtReal = lambda s,l,toks: float(toks[0]) 60cvtDict = lambda s,l,toks: dict(toks[0]) 61 62lbrack = Literal("[").suppress() 63rbrack = Literal("]").suppress() 64lbrace = Literal("{").suppress() 65rbrace = Literal("}").suppress() 66colon = Literal(":").suppress() 67integer = Word(nums).setName("integer").setParseAction( cvtInt ) 68real = Regex(r'[+-]?\d+\.\d*').setName("real").setParseAction( cvtReal ) 69 70tupleStr = Forward() 71listStr = Forward() 72dictStr = Forward() 73listItem = real | integer | quotedString.setParseAction(removeQuotes) | Group(listStr) | tupleStr | dictStr 74tupleStr <<= ( Suppress("(") + delimitedList(listItem) + Optional(Suppress(",")) + Suppress(")") ) 75tupleStr.setParseAction( lambda t:tuple(t.asList()) ) 76listStr <<= (lbrack + Optional(delimitedList(listItem)) + Optional(Suppress(",")) + rbrack) 77dictKeyStr = real | integer | quotedString.setParseAction(removeQuotes) 78dictStr <<= lbrace + Optional(delimitedList( Group( dictKeyStr + colon + listItem ))) + Optional(Suppress(",")) + rbrace 79dictStr.setParseAction(lambda t: {k_v[0]:(k_v[1].asList() if isinstance(k_v[1],ParseResults) else k_v[1]) for k_v in t}) 80 81test = '[{0: [2], 1: []}, {0: [], 1: [], 2: [,]}, {0: [1, 2,],}]' 82print(listStr.parseString(test)) 83