# parseListString.py # # Copyright, 2006, by Paul McGuire # from pyparsing import * # first pass lbrack = Literal("[") rbrack = Literal("]") integer = Word(nums).setName("integer") real = Combine(Optional(oneOf("+ -")) + Word(nums) + "." + Optional(Word(nums))).setName("real") listItem = real | integer | quotedString listStr = lbrack + delimitedList(listItem) + rbrack test = "['a', 100, 3.14]" print listStr.parseString(test) # second pass, cleanup and add converters lbrack = Literal("[").suppress() rbrack = Literal("]").suppress() cvtInt = lambda s,l,toks: int(toks[0]) integer = Word(nums).setName("integer").setParseAction( cvtInt ) cvtReal = lambda s,l,toks: float(toks[0]) real = Combine(Optional(oneOf("+ -")) + Word(nums) + "." + Optional(Word(nums))).setName("real").setParseAction( cvtReal ) listItem = real | integer | quotedString.setParseAction( removeQuotes ) listStr = lbrack + delimitedList(listItem) + rbrack test = "['a', 100, 3.14]" print listStr.parseString(test) # third pass, add nested list support, and tuples, too! cvtInt = lambda s,l,toks: int(toks[0]) cvtReal = lambda s,l,toks: float(toks[0]) lbrack = Literal("[").suppress() rbrack = Literal("]").suppress() integer = Word(nums).setName("integer").setParseAction( cvtInt ) real = Combine(Optional(oneOf("+ -")) + Word(nums) + "." + Optional(Word(nums))).setName("real").setParseAction( cvtReal ) tupleStr = Forward() listStr = Forward() listItem = real | integer | quotedString.setParseAction(removeQuotes) | Group(listStr) | tupleStr tupleStr << ( Suppress("(") + delimitedList(listItem) + Optional(Suppress(",")) + Suppress(")") ) tupleStr.setParseAction( lambda t:tuple(t.asList()) ) listStr << lbrack + delimitedList(listItem) + Optional(Suppress(",")) + rbrack test = "['a', 100, ('A', [101,102]), 3.14, [ +2.718, 'xyzzy', -1.414] ]" print listStr.parseString(test) # fourth pass, just parsing tuples of numbers #~ from pyparsing import * #~ integer = (Word(nums)|Word('-+',nums)).setName("integer") #~ real = Combine(integer + "." + Optional(Word(nums))).setName("real") #~ tupleStr = Forward().setName("tuple") #~ tupleItem = real | integer | tupleStr #~ tupleStr << ( Suppress("(") + delimitedList(tupleItem) + #~ Optional(Suppress(",")) + Suppress(")") ) #~ # add parse actions to do conversion during parsing #~ integer.setParseAction( lambda toks: int(toks[0]) ) #~ real.setParseAction( lambda toks: float(toks[0]) ) #~ tupleStr.setParseAction( lambda toks: tuple(toks) ) #~ s = '((1,2), (3,4), (-5,9.2),)' #~ print tupleStr.parseString(s)[0] cvtInt = lambda s,l,toks: int(toks[0]) cvtReal = lambda s,l,toks: float(toks[0]) cvtDict = lambda s,l,toks: dict(toks[0]) lbrack = Literal("[").suppress() rbrack = Literal("]").suppress() lbrace = Literal("{").suppress() rbrace = Literal("}").suppress() colon = Literal(":").suppress() integer = Word(nums).setName("integer").setParseAction( cvtInt ) real = Combine(Optional(oneOf("+ -")) + Word(nums) + "." + Optional(Word(nums))).setName("real").setParseAction( cvtReal ) tupleStr = Forward() listStr = Forward() dictStr = Forward() listItem = real | integer | quotedString.setParseAction(removeQuotes) | Group(listStr) | tupleStr | dictStr tupleStr << ( Suppress("(") + delimitedList(listItem) + Optional(Suppress(",")) + Suppress(")") ) tupleStr.setParseAction( lambda t:tuple(t.asList()) ) listStr << lbrack + delimitedList(listItem) + Optional(Suppress(",")) + rbrack dictStr << rbrace + delimitedList( Group( listItem + colon + listItem ) ) + rbrace test = "['a', 100, ('A', [101,102]), 3.14, [ +2.718, 'xyzzy', -1.414] ]" test = '[{0: [2], 1: []}, {0: [], 1: [], 2: []}, {0: [1, 2]}]' print listStr.parseString(test)