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########################################################################
# $Header: /var/local/cvsroot/4Suite/Ft/Xml/XPath/ParsedPredicateList.py,v 1.7 2005/03/06 11:20:37 mbrown Exp $
"""
A parsed token that represents a predicate list.
Copyright 2005 Fourthought, Inc. (USA).
Detailed license and copyright information: http://4suite.org/COPYRIGHT
Project home, documentation, distributions: http://4suite.org/
"""
from Ft.Lib import number
from Ft.Xml.XPath import Conversions
from Ft.Xml.XPath.Types import NumberTypes, g_xpathPrimitiveTypes
__all__ = ['ParsedPredicateList']
class ParsedPredicateList:
def __init__(self, preds):
if isinstance(preds, tuple):
preds = list(preds)
elif not isinstance(preds, list):
raise TypeError("Invalid Predicates: %s"%str(preds))
self._predicates = preds
self._length = len(preds)
def append(self,pred):
self._predicates.append(pred)
self._length += 1
def filter(self, nodeList, context, reverse):
if self._length:
state = context.copy()
for pred in self._predicates:
size = len(nodeList)
ctr = 0
current = nodeList
nodeList = []
for node in current:
position = (reverse and size - ctr) or (ctr + 1)
context.node, context.position, context.size = \
node, position, size
res = pred.evaluate(context)
if type(res) in NumberTypes:
# This must be separate to prevent falling into
# the boolean check.
if not number.isnan(res) and res == position:
nodeList.append(node)
elif Conversions.BooleanValue(res):
nodeList.append(node)
ctr += 1
context.set(state)
return nodeList
def __getitem__(self, index):
return self._predicates[index]
def __len__(self):
return self._length
def pprint(self, indent=''):
print indent + str(self)
for pred in self._predicates:
pred.pprint(indent + ' ')
def __str__(self):
return '<PredicateList at %x: %s>' % (
id(self),
repr(self) or '(empty)',
)
def __repr__(self):
return reduce(lambda result, pred:
result + '[%s]' % repr(pred),
self._predicates,
''
)
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