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A collection of tests for ANTLR 4 Runtime libraries.
#
# Represent a subset of XPath XML path syntax for use in identifying nodes in
# parse trees.
#
#
# Split path into words and separators {@code /} and {@code //} via ANTLR
# itself then walk path elements from left to right. At each separator-word
# pair, find set of nodes. Next stage uses those as work list.
#
#
# The basic interface is
# {@link XPath#findAll ParseTree.findAll}{@code (tree, pathString, parser)}.
# But that is just shorthand for:
#
#
# {@link XPath} p = new {@link XPath#XPath XPath}(parser, pathString);
# return p.{@link #evaluate evaluate}(tree);
#
#
#
# See {@code org.antlr.v4.test.TestXPath} for descriptions. In short, this
# allows operators:
#
#
# - /
- root
# - //
- anywhere
# - !
- invert; this must appear directly after root or anywhere
# operator
#
#
#
# and path elements:
#
#
# - ID
- token name
# - 'string'
- any string literal token from the grammar
# - expr
- rule name
# - *
- wildcard matching any node
#
#
#
# Whitespace is not allowed.
#
from antlr4 import CommonTokenStream, DFA, PredictionContextCache, Lexer, LexerATNSimulator, ParserRuleContext, TerminalNode
from antlr4.atn.ATNDeserializer import ATNDeserializer
from antlr4.InputStream import InputStream
from antlr4.Token import Token
from antlr4.error.ErrorListener import ErrorListener
from antlr4.error.Errors import LexerNoViableAltException
from antlr4.tree.Trees import Trees
from io import StringIO
def serializedATN():
with StringIO() as buf:
buf.write(u"\3\u0430\ud6d1\u8206\uad2d\u4417\uaef1\u8d80\uaadd\2")
buf.write(u"\n\64\b\1\4\2\t\2\4\3\t\3\4\4\t\4\4\5\t\5\4\6\t\6\4\7")
buf.write(u"\t\7\4\b\t\b\4\t\t\t\3\2\3\2\3\2\3\3\3\3\3\4\3\4\3\5")
buf.write(u"\3\5\3\6\3\6\7\6\37\n\6\f\6\16\6\"\13\6\3\6\3\6\3\7\3")
buf.write(u"\7\5\7(\n\7\3\b\3\b\3\t\3\t\7\t.\n\t\f\t\16\t\61\13\t")
buf.write(u"\3\t\3\t\3/\2\n\3\5\5\6\7\7\t\b\13\t\r\2\17\2\21\n\3")
buf.write(u"\2\4\7\2\62;aa\u00b9\u00b9\u0302\u0371\u2041\u2042\17")
buf.write(u"\2C\\c|\u00c2\u00d8\u00da\u00f8\u00fa\u0301\u0372\u037f")
buf.write(u"\u0381\u2001\u200e\u200f\u2072\u2191\u2c02\u2ff1\u3003")
buf.write(u"\ud801\uf902\ufdd1\ufdf2\uffff\64\2\3\3\2\2\2\2\5\3\2")
buf.write(u"\2\2\2\7\3\2\2\2\2\t\3\2\2\2\2\13\3\2\2\2\2\21\3\2\2")
buf.write(u"\2\3\23\3\2\2\2\5\26\3\2\2\2\7\30\3\2\2\2\t\32\3\2\2")
buf.write(u"\2\13\34\3\2\2\2\r\'\3\2\2\2\17)\3\2\2\2\21+\3\2\2\2")
buf.write(u"\23\24\7\61\2\2\24\25\7\61\2\2\25\4\3\2\2\2\26\27\7\61")
buf.write(u"\2\2\27\6\3\2\2\2\30\31\7,\2\2\31\b\3\2\2\2\32\33\7#")
buf.write(u"\2\2\33\n\3\2\2\2\34 \5\17\b\2\35\37\5\r\7\2\36\35\3")
buf.write(u"\2\2\2\37\"\3\2\2\2 \36\3\2\2\2 !\3\2\2\2!#\3\2\2\2\"")
buf.write(u" \3\2\2\2#$\b\6\2\2$\f\3\2\2\2%(\5\17\b\2&(\t\2\2\2\'")
buf.write(u"%\3\2\2\2\'&\3\2\2\2(\16\3\2\2\2)*\t\3\2\2*\20\3\2\2")
buf.write(u"\2+/\7)\2\2,.\13\2\2\2-,\3\2\2\2.\61\3\2\2\2/\60\3\2")
buf.write(u"\2\2/-\3\2\2\2\60\62\3\2\2\2\61/\3\2\2\2\62\63\7)\2\2")
buf.write(u"\63\22\3\2\2\2\6\2 \'/\3\3\6\2")
return buf.getvalue()
class XPathLexer(Lexer):
atn = ATNDeserializer().deserialize(serializedATN())
decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
TOKEN_REF = 1
RULE_REF = 2
ANYWHERE = 3
ROOT = 4
WILDCARD = 5
BANG = 6
ID = 7
STRING = 8
modeNames = [ u"DEFAULT_MODE" ]
literalNames = [ u"",
u"'//'", u"'/'", u"'*'", u"'!'" ]
symbolicNames = [ u"",
u"TOKEN_REF", u"RULE_REF", u"ANYWHERE", u"ROOT", u"WILDCARD",
u"BANG", u"ID", u"STRING" ]
ruleNames = [ u"ANYWHERE", u"ROOT", u"WILDCARD", u"BANG", u"ID", u"NameChar",
u"NameStartChar", u"STRING" ]
grammarFileName = u"XPathLexer.g4"
def __init__(self, input=None):
super(XPathLexer, self).__init__(input)
self.checkVersion("4.5")
self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
self._actions = None
self._predicates = None
def action(self, localctx, ruleIndex, actionIndex):
if self._actions is None:
actions = dict()
actions[4] = self.ID_action
self._actions = actions
action = self._actions.get(ruleIndex, None)
if action is not None:
action(localctx, actionIndex)
else:
raise Exception("No registered action for:" + str(ruleIndex))
def ID_action(self, localctx , actionIndex):
if actionIndex == 0:
char = self.text[0]
if char.isupper():
self.type = XPathLexer.TOKEN_REF
else:
self.type = XPathLexer.RULE_REF
class XPath(object):
WILDCARD = "*" # word not operator/separator
NOT = "!" # word for invert operator
def __init__(self, parser, path):
self.parser = parser
self.path = path
self.elements = self.split(path)
def split(self, path):
input = InputStream(path)
lexer = XPathLexer(input)
def recover(self, e):
raise e
lexer.recover = recover
lexer.removeErrorListeners()
lexer.addErrorListener(ErrorListener()) # XPathErrorListener does no more
tokenStream = CommonTokenStream(lexer)
try:
tokenStream.fill()
except LexerNoViableAltException as e:
pos = lexer.getColumn()
msg = "Invalid tokens or characters at index " + str(pos) + " in path '" + path + "'"
raise Exception(msg, e)
tokens = tokenStream.getTokens()
elements = list()
n = len(tokens)
i=0
while i < n :
el = tokens[i]
next = None
if el.type in [XPathLexer.ROOT, XPathLexer.ANYWHERE]:
anywhere = el.type == XPathLexer.ANYWHERE
i += 1
next = tokens[i]
invert = next.type==XPathLexer.BANG
if invert:
i += 1
next = tokens[i]
pathElement = self.getXPathElement(next, anywhere)
pathElement.invert = invert
elements.append(pathElement)
i += 1
elif el.type in [XPathLexer.TOKEN_REF, XPathLexer.RULE_REF, XPathLexer.WILDCARD] :
elements.append( self.getXPathElement(el, False) )
i += 1
elif el.type==Token.EOF :
break
else:
raise Exception("Unknown path element " + str(el))
return elements
#
# Convert word like {@code#} or {@code ID} or {@code expr} to a path
# element. {@code anywhere} is {@code true} if {@code //} precedes the
# word.
#
def getXPathElement(self, wordToken, anywhere):
if wordToken.type==Token.EOF:
raise Exception("Missing path element at end of path")
word = wordToken.text
ttype = self.parser.getTokenType(word)
ruleIndex = self.parser.getRuleIndex(word)
if wordToken.type==XPathLexer.WILDCARD :
return XPathWildcardAnywhereElement() if anywhere else XPathWildcardElement()
elif wordToken.type in [XPathLexer.TOKEN_REF, XPathLexer.STRING]:
if ttype==Token.INVALID_TYPE:
raise Exception( word + " at index " + str(wordToken.startIndex) + " isn't a valid token name")
return XPathTokenAnywhereElement(word, ttype) if anywhere else XPathTokenElement(word, ttype)
else:
if ruleIndex==-1:
raise Exception( word + " at index " + str(wordToken.getStartIndex()) + " isn't a valid rule name")
return XPathRuleAnywhereElement(word, ruleIndex) if anywhere else XPathRuleElement(word, ruleIndex)
def findAll(self, tree, xpath, parser):
p = XPath(parser, xpath)
return p.evaluate(tree)
#
# Return a list of all nodes starting at {@code t} as root that satisfy the
# path. The root {@code /} is relative to the node passed to
# {@link #evaluate}.
#
def evaluate(self, t):
dummyRoot = ParserRuleContext()
dummyRoot.children = [t] # don't set t's parent.
work = [dummyRoot]
for i in range(0, len(self.elements)):
next = set()
for node in work:
if len( node.children) > 0 :
# only try to match next element if it has children
# e.g., //func/*/stat might have a token node for which
# we can't go looking for stat nodes.
matching = self.elements[i].evaluate(node)
next |= matching
i += 1
work = next
return work
class XPathElement(object):
def __init__(self, nodeName):
self.nodeName = nodeName
self.invert = False
def __str__(self):
return unicode(self)
def __unicode__(self):
return type(self).__name__ + "[" + ("!" if self.invert else "") + self.nodeName + "]"
#
# Either {@code ID} at start of path or {@code ...//ID} in middle of path.
#
class XPathRuleAnywhereElement(XPathElement):
def __init__(self, ruleName, ruleIndex):
super(XPathRuleAnywhereElement, self).__init__(ruleName)
self.ruleIndex = ruleIndex
def evaluate(self, t):
return Trees.findAllRuleNodes(t, self.ruleIndex)
class XPathRuleElement(XPathElement):
def __init__(self, ruleName, ruleIndex):
super(XPathRuleElement, self).__init__(ruleName)
self.ruleIndex = ruleIndex
def evaluate(self, t):
# return all children of t that match nodeName
nodes = []
for c in Trees.getChildren(t):
if isinstance(c, ParserRuleContext ):
if (c.ruleIndex == self.ruleIndex ) == (not self.invert):
nodes.append(c)
return nodes
class XPathTokenAnywhereElement(XPathElement):
def __init__(self, ruleName, tokenType):
super(XPathTokenAnywhereElement, self).__init__(ruleName)
self.tokenType = tokenType
def evaluate(self, t):
return Trees.findAllTokenNodes(t, self.tokenType)
class XPathTokenElement(XPathElement):
def __init__(self, ruleName, tokenType):
super(XPathTokenElement, self).__init__(ruleName)
self.tokenType = tokenType
def evaluate(self, t):
# return all children of t that match nodeName
nodes = []
for c in Trees.getChildren(t):
if isinstance(c, TerminalNode):
if (c.symbol.type == self.tokenType ) == (not self.invert):
nodes.append(c)
return nodes
class XPathWildcardAnywhereElement(XPathElement):
def __init__(self):
super(XPathWildcardAnywhereElement, self).__init__(XPath.WILDCARD)
def evaluate(self, t):
if self.invert:
return list() # !* is weird but valid (empty)
else:
return Trees.descendants(t)
class XPathWildcardElement(XPathElement):
def __init__(self):
super(XPathWildcardElement, self).__init__(XPath.WILDCARD)
def evaluate(self, t):
if self.invert:
return list() # !* is weird but valid (empty)
else:
return Trees.getChildren(t) © 2015 - 2025 Weber Informatics LLC | Privacy Policy