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aaronmk
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# A general recursive descent parser
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from Parser import Parser
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class XpathElem:
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def __init__(self, name, value=None, is_attr=False, attrs=None):
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if attrs == None: attrs = []
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self.name = name
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self.value = value
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self.is_attr = is_attr
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self.attrs = attrs
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def __repr__(self):
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if self.is_attr: prefix = '@'
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else: prefix = ''
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return prefix+self.name+repr(self.attrs)+'='+repr(self.value)
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def __eq__(self, other): return self.__dict__ == other.__dict__
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class XpathParser(Parser):
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def _main(self):
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while True:
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self._match_str('/', required=True)
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tree = self._path() # just use last path for now
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if not self._match_str('->'): break
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return tree
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def _path(self):
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tree = []
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while True:
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elem = XpathElem(is_attr=self._match_str('@'), name=self._fields())
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if self._match_str('['):
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elem.attrs = self._attrs()
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self._match_str(']', required=True)
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tree.append(elem)
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if not self._match_str('/'): break
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return tree
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def _fields(self):
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if self._match_str('{'):
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tree = []
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while True:
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tree.append(self._field())
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if not self._match_str(','): break
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self._match_str('}', required=True)
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tree = tuple(tree)
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tree = tree[0] # just use first field for now
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else: tree = self._field()
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return tree
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def _attrs(self):
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tree = []
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while True:
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path = self._path()
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self._match_str('=', required=True)
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path[-1].value = self._value()
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tree.append(path)
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if not self._match_str(','): break
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return tree
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def _field(self):
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return self._name()
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def _name(self): return self._match_re(r'[\w.]+', required=True)
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def _value(self): return self._match_re(r'[\w|]+', required=True)
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