def __init__(self, grammar):
self._grammar = grammar
self._lexer = Lexer()
for tt in self._grammar.getTokenTypes():
self._lexer.addTokenType(tt)
self._curFile = None
class Parser(object):
def __init__(self, grammar):
self._grammar = grammar
self._lexer = Lexer()
for tt in self._grammar.getTokenTypes():
self._lexer.addTokenType(tt)
self._curFile = None
def enableLineComments(self, lineCommentStart='//'):
self._lexer.enableLineComments(lineCommentStart)
def enableBlockComments(self,
blockCommentStart='/*',
blockCommentEnd='*/'
):
self._lexer.enableBlockComments(blockCommentStart, blockCommentEnd)
def parse(self, inStream):
self._lexer.setInputStream(inStream)
self._tokenBuffer = []
path = Path()
path.push(self._grammar.getSocket(), None)
error = False
done = False
while not done:
token = self._getNextToken()
if not token:
found, path = self._findPathToEnd(path)
if found:
done = True
else:
found, path = self._findNextSibling(path)
if not found:
error = True
done = True
continue
found, path = self._findNextMatchingNode(token, path)
if found:
self._tokenBuffer.pop()
else:
found, path = self._findNextSibling(path)
if not found:
done = True
error = True
if not error:
return self._createAst(path)
else:
if self._tokenBuffer:
token = self._tokenBuffer[0]
text = token.getText()
line, column = token.getStartPosition()
raise ParseError(self._curFile, line, column, text)
else:
raise Exception("Parsing error")
def parseFile(self, filePath):
self._curFile = filePath
res = self.parse(FileInput(filePath))
self._curFile = None
return res
def parseString(self, string):
return self.parse(StringInput(string))
def _createAst(self, path):
stack = []
current = None
numElements = path.getLength()
for i in range(numElements):
element = path.getElement(i)
node = element.getGrammarNode()
token = element.getToken()
if node.isRuleStart():
if current:
stack.append(current)
name = node.getName()
id_ = node.getId()
text = token and token.getText() or ''
current = AstNode(name, text, id_)
elif node.isRuleEnd():
# Ggf. Transformation. Dabei ID aus Regel bewahren:
tmp = current;
current = node.transform(current)
if current is not tmp:
current.setId(tmp.getId())
parent = stack and stack.pop() or None
if parent:
parent.addChild(current)
current = parent
else:
break
elif node.isTokenNode():
id_ = node.getId()
text = token and token.getText() or ''
current.addChild(AstNode('token', text, id_))
else:
continue
return current
def _findNextSibling(self, path):
removed = []
while True:
if path.getLength() < 2:
# Ursprünglichen Pfad wiederherstellen:
while removed:
elem = removed.pop()
token = elem.getToken()
if token:
self._tokenBuffer.pop()
path.push(elem.getGrammarNode(), token)
return False, path
siblingFound, path = self._gotoNextSibling(path)
if siblingFound:
return True, path
else:
elem = path.pop()
token = elem.getToken()
removed.append(elem)
if token:
self._tokenBuffer.append(token)
def _gotoNextSibling(self, path):
if path.getLength() < 2:
return False, path
elem = path.pop()
start = elem.getGrammarNode()
token = elem.getToken()
prev = path.getElement(-1).getGrammarNode()
context = Context(path, token)
try:
successors = prev.getSuccessors(context)
except SuccessorError:
path.push(start, token)
return False, path
try:
idx = successors.index(start)
if idx < len(successors) - 1:
sibling = successors[idx+1]
if token:
self._tokenBuffer.append(token)
path.push(sibling, None)
return True, path
else:
path.push(start, token)
return False, path
except ValueError:
path.push(start, token)
return False, path
def _getNextToken(self):
if not self._tokenBuffer:
token = self._lexer.getNextToken();
if token:
self._tokenBuffer.append(token)
if self._tokenBuffer:
return self._tokenBuffer[-1]
else:
return None
def _findNextMatchingNode(self, token, path):
elem = path.getElement(-1)
startNode = elem.getGrammarNode()
startToken = elem.getToken()
if startNode.isTokenNode() and startToken is None:
if startNode.getTokenTypeId() in token.getTypeIds():
path.pop()
path.push(startNode, token)
return True, path
else:
return False, path
try:
successors = startNode.getSuccessors(Context(path, token))
except SuccessorError:
return False, path
for succ in successors:
path.push(succ, None)
found, path = self._findNextMatchingNode(token, path);
if found:
return found, path
else:
path.pop()
return False, path
def _findPathToEnd(self, path):
node = path.getElement(-1).getGrammarNode()
try:
successors = node.getSuccessors(Context(path))
except SuccessorError:
return False, path
if not successors:
return True, path # Fertig!
for succ in successors:
if succ.isTokenNode():
continue
path.push(succ, None)
found, path = self._findPathToEnd(path);
if found:
return found, path
else:
path.pop()
return False, path