"""ANTLR3 exception hierarchy"""

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# Copyright (c) 2005-2008 Terence Parr

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from antlr3.constants import INVALID_TOKEN_TYPE

class BacktrackingFailed(Exception):

    """@brief Raised to signal failed backtrack attempt"""

    pass

class RecognitionException(Exception):

    """@brief The root of the ANTLR exception hierarchy.

    To avoid English-only error messages and to generally make things

    as flexible as possible, these exceptions are not created with strings,

    but rather the information necessary to generate an error.  Then

    the various reporting methods in Parser and Lexer can be overridden

    to generate a localized error message.  For example, MismatchedToken

    exceptions are built with the expected token type.

    So, don't expect getMessage() to return anything.

    Note that as of Java 1.4, you can access the stack trace, which means

    that you can compute the complete trace of rules from the start symbol.

    This gives you considerable context information with which to generate

    useful error messages.

    ANTLR generates code that throws exceptions upon recognition error and

    also generates code to catch these exceptions in each rule.  If you

    want to quit upon first error, you can turn off the automatic error

    handling mechanism using rulecatch action, but you still need to

    override methods mismatch and recoverFromMismatchSet.

    In general, the recognition exceptions can track where in a grammar a

    problem occurred and/or what was the expected input.  While the parser

    knows its state (such as current input symbol and line info) that

    state can change before the exception is reported so current token index

    is computed and stored at exception time.  From this info, you can

    perhaps print an entire line of input not just a single token, for example.

    Better to just say the recognizer had a problem and then let the parser

    figure out a fancy report.

    """

    def __init__(self, input=None):

        Exception.__init__(self)

	# What input stream did the error occur in?

        self.input = None

        # What is index of token/char were we looking at when the error

        # occurred?

        self.index = None

	# The current Token when an error occurred.  Since not all streams

	# can retrieve the ith Token, we have to track the Token object.

	# For parsers.  Even when it's a tree parser, token might be set.

        self.token = None

	# If this is a tree parser exception, node is set to the node with

	# the problem.

        self.node = None

	# The current char when an error occurred. For lexers.

        self.c = None

	# Track the line at which the error occurred in case this is

	# generated from a lexer.  We need to track this since the

        # unexpected char doesn't carry the line info.

        self.line = None

        self.charPositionInLine = None

        # If you are parsing a tree node stream, you will encounter som

        # imaginary nodes w/o line/col info.  We now search backwards looking

        # for most recent token with line/col info, but notify getErrorHeader()

        # that info is approximate.

        self.approximateLineInfo = False

        if input is not None:

            self.input = input

            self.index = input.index()

            # late import to avoid cyclic dependencies

            from antlr3.streams import TokenStream, CharStream

            from antlr3.tree import TreeNodeStream

            if isinstance(self.input, TokenStream):

                self.token = self.input.LT(1)

                self.line = self.token.line

                self.charPositionInLine = self.token.charPositionInLine

            if isinstance(self.input, TreeNodeStream):

                self.extractInformationFromTreeNodeStream(self.input)

            else:

                if isinstance(self.input, CharStream):

                    self.c = self.input.LT(1)

                    self.line = self.input.line

                    self.charPositionInLine = self.input.charPositionInLine

                else:

                    self.c = self.input.LA(1)

    def extractInformationFromTreeNodeStream(self, nodes):

        from antlr3.tree import Tree, CommonTree

        from antlr3.tokens import CommonToken

        self.node = nodes.LT(1)

        adaptor = nodes.adaptor

        payload = adaptor.getToken(self.node)

        if payload is not None:

            self.token = payload

            if payload.line <= 0:

                # imaginary node; no line/pos info; scan backwards

                i = -1

                priorNode = nodes.LT(i)

                while priorNode is not None:

                    priorPayload = adaptor.getToken(priorNode)

                    if priorPayload is not None and priorPayload.line > 0:

                        # we found the most recent real line / pos info

                        self.line = priorPayload.line

                        self.charPositionInLine = priorPayload.charPositionInLine

                        self.approximateLineInfo = True

                        break

                    i -= 1

                    priorNode = nodes.LT(i)

            else: # node created from real token

                self.line = payload.line

                self.charPositionInLine = payload.charPositionInLine

        elif isinstance(self.node, Tree):

            self.line = self.node.line

            self.charPositionInLine = self.node.charPositionInLine

            if isinstance(self.node, CommonTree):

                self.token = self.node.token

        else:

            type = adaptor.getType(self.node)

            text = adaptor.getText(self.node)

            self.token = CommonToken(type=type, text=text)

    def getUnexpectedType(self):

        """Return the token type or char of the unexpected input element"""

        from antlr3.streams import TokenStream

        from antlr3.tree import TreeNodeStream

        if isinstance(self.input, TokenStream):

            return self.token.type

        elif isinstance(self.input, TreeNodeStream):

            adaptor = self.input.treeAdaptor

            return adaptor.getType(self.node)

        else:

            return self.c

    unexpectedType = property(getUnexpectedType)

class MismatchedTokenException(RecognitionException):

    """@brief A mismatched char or Token or tree node."""

    def __init__(self, expecting, input):

        RecognitionException.__init__(self, input)

        self.expecting = expecting

    def __str__(self):

        #return "MismatchedTokenException("+self.expecting+")"

        return "MismatchedTokenException(%r!=%r)" % (

            self.getUnexpectedType(), self.expecting

            )

    __repr__ = __str__

class UnwantedTokenException(MismatchedTokenException):

    """An extra token while parsing a TokenStream"""

    def getUnexpectedToken(self):

        return self.token

    def __str__(self):

        exp = ", expected %s" % self.expecting

        if self.expecting == INVALID_TOKEN_TYPE:

            exp = ""

        if self.token is None:

            return "UnwantedTokenException(found=%s%s)" % (None, exp)

        return "UnwantedTokenException(found=%s%s)" % (self.token.text, exp)

    __repr__ = __str__

class MissingTokenException(MismatchedTokenException):

    """

    We were expecting a token but it's not found.  The current token

    is actually what we wanted next.

    """

    def __init__(self, expecting, input, inserted):

        MismatchedTokenException.__init__(self, expecting, input)

        self.inserted = inserted

    def getMissingType(self):

        return self.expecting

    def __str__(self):

        if self.inserted is not None and self.token is not None:

            return "MissingTokenException(inserted %r at %r)" % (

                self.inserted, self.token.text)

        if self.token is not None:

            return "MissingTokenException(at %r)" % self.token.text

        return "MissingTokenException"

    __repr__ = __str__

class MismatchedRangeException(RecognitionException):

    """@brief The next token does not match a range of expected types."""

    def __init__(self, a, b, input):

        RecognitionException.__init__(self, input)

        self.a = a

        self.b = b

    def __str__(self):

        return "MismatchedRangeException(%r not in [%r..%r])" % (

            self.getUnexpectedType(), self.a, self.b

            )

    __repr__ = __str__

class MismatchedSetException(RecognitionException):

    """@brief The next token does not match a set of expected types."""

    def __init__(self, expecting, input):

        RecognitionException.__init__(self, input)

        self.expecting = expecting

    def __str__(self):

        return "MismatchedSetException(%r not in %r)" % (

            self.getUnexpectedType(), self.expecting

            )

    __repr__ = __str__

class MismatchedNotSetException(MismatchedSetException):

    """@brief Used for remote debugger deserialization"""

    def __str__(self):

        return "MismatchedNotSetException(%r!=%r)" % (

            self.getUnexpectedType(), self.expecting

            )

    __repr__ = __str__

class NoViableAltException(RecognitionException):

    """@brief Unable to decide which alternative to choose."""

    def __init__(

        self, grammarDecisionDescription, decisionNumber, stateNumber, input

        ):

        RecognitionException.__init__(self, input)

        self.grammarDecisionDescription = grammarDecisionDescription

        self.decisionNumber = decisionNumber

        self.stateNumber = stateNumber

    def __str__(self):

        return "NoViableAltException(%r!=[%r])" % (

            self.unexpectedType, self.grammarDecisionDescription

            )

    __repr__ = __str__

class EarlyExitException(RecognitionException):

    """@brief The recognizer did not match anything for a (..)+ loop."""

    def __init__(self, decisionNumber, input):

        RecognitionException.__init__(self, input)

        self.decisionNumber = decisionNumber

class FailedPredicateException(RecognitionException):

    """@brief A semantic predicate failed during validation.

    Validation of predicates

    occurs when normally parsing the alternative just like matching a token.

    Disambiguating predicate evaluation occurs when we hoist a predicate into

    a prediction decision.

    """

    def __init__(self, input, ruleName, predicateText):

        RecognitionException.__init__(self, input)

        self.ruleName = ruleName

        self.predicateText = predicateText

    def __str__(self):

        return "FailedPredicateException("+self.ruleName+",{"+self.predicateText+"}?)"

    __repr__ = __str__

class MismatchedTreeNodeException(RecognitionException):

    """@brief The next tree mode does not match the expected type."""

    def __init__(self, expecting, input):

        RecognitionException.__init__(self, input)

        self.expecting = expecting

    def __str__(self):

        return "MismatchedTreeNodeException(%r!=%r)" % (

            self.getUnexpectedType(), self.expecting

            )

    __repr__ = __str__