tree.py

antlr最新版本V3源代码

""" @package antlr3.tree
@brief ANTLR3 runtime package, tree module

This module contains all support classes for AST construction and tree parsers.

"""

# begin[licence]
#
# [The "BSD licence"]
# Copyright (c) 2005-2006 Terence Parr
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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# end[licence]

# lot's of docstrings are missing, don't complain for now...
# pylint: disable-msg=C0111

import warnings

from antlr3.constants import UP, DOWN, EOF, INVALID_TOKEN_TYPE
from antlr3.recognizers import BaseRecognizer
from antlr3.streams import IntStream
from antlr3.tokens import CommonToken, Token, INVALID_TOKEN
from antlr3.exceptions import MismatchedTreeNodeException

############################################################################
#
# tree related exceptions
#
############################################################################


class RewriteCardinalityException(RuntimeError):
    """
    @brief Base class for all exceptions thrown during AST rewrite construction.

    This signifies a case where the cardinality of two or more elements
    in a subrule are different: (ID INT)+ where |ID|!=|INT|
    """

    def __init__(self, elementDescription):
        RuntimeError.__init__(self, elementDescription)

        self.elementDescription = elementDescription


    def getMessage(self):
        return self.elementDescription


class RewriteEarlyExitException(RewriteCardinalityException):
    """@brief No elements within a (...)+ in a rewrite rule"""

    def __init__(self, elementDescription=None):
        RewriteCardinalityException.__init__(self, elementDescription)


class RewriteEmptyStreamException(RewriteCardinalityException):
    """
    @brief Ref to ID or expr but no tokens in ID stream or subtrees in expr stream
    """

    pass


############################################################################
#
# basic Tree and TreeAdaptor interfaces
#
############################################################################

class Tree(object):
    """
    @brief Abstract baseclass for tree nodes.
    
    What does a tree look like?  ANTLR has a number of support classes
    such as CommonTreeNodeStream that work on these kinds of trees.  You
    don't have to make your trees implement this interface, but if you do,
    you'll be able to use more support code.

    NOTE: When constructing trees, ANTLR can build any kind of tree; it can
    even use Token objects as trees if you add a child list to your tokens.
    
    This is a tree node without any payload; just navigation and factory stuff.
    """


    def getChild(self, i):
        raise NotImplementedError
    

    def getChildCount(self):
        raise NotImplementedError
    

    def addChild(self, t):
        """
        Add t as a child to this node.  If t is null, do nothing.  If t
        is nil, add all children of t to this' children.
        @param t
        """

        raise NotImplementedError
    

    def isNil(self):
        """
        Indicates the node is a nil node but may still have children, meaning
        the tree is a flat list.
        """

        raise NotImplementedError
    

    def getTokenStartIndex(self):
        """
        What is the smallest token index (indexing from 0) for this node
           and its children?
        """

        raise NotImplementedError


    def setTokenStartIndex(self, index):
        raise NotImplementedError


    def getTokenStopIndex(self):
        """
        What is the largest token index (indexing from 0) for this node
        and its children?
        """

        raise NotImplementedError


    def setTokenStopIndex(self, index):
        raise NotImplementedError


    def dupTree(self):
        raise NotImplementedError
    

    def dupNode(self):
        raise NotImplementedError
    

    def getType(self):
        """Return a token type; needed for tree parsing."""

        raise NotImplementedError
    

    def getText(self):
        raise NotImplementedError
    

    def getLine(self):
        """In case we don't have a token payload, what is the line for errors?"""

        raise NotImplementedError
    

    def getCharPositionInLine(self):
        raise NotImplementedError


    def toStringTree(self):
        raise NotImplementedError


    def toString(self):
        raise NotImplementedError



class TreeAdaptor(object):
    """
    @brief Abstract baseclass for tree adaptors.
    
    How to create and navigate trees.  Rather than have a separate factory
    and adaptor, I've merged them.  Makes sense to encapsulate.

    This takes the place of the tree construction code generated in the
    generated code in 2.x and the ASTFactory.

    I do not need to know the type of a tree at all so they are all
    generic Objects.  This may increase the amount of typecasting needed. :(
    """
    
    # C o n s t r u c t i o n

    def createWithPayload(self, payload):
        """
        Create a tree node from Token object; for CommonTree type trees,
        then the token just becomes the payload.  This is the most
        common create call.
        """

        raise NotImplementedError
    

    def dupTree(self, tree):
        """Duplicate tree recursively, using dupNode() for each node"""

        raise NotImplementedError


    def dupNode(self, treeNode):
        """Duplicate a single tree node"""

        raise NotImplementedError


    def nil(self):
        """
        Return a nil node (an empty but non-null node) that can hold
        a list of element as the children.  If you want a flat tree (a list)
        use "t=adaptor.nil(); t.addChild(x); t.addChild(y);"
        """

        raise NotImplementedError


    def isNil(self, tree):
        """Is tree considered a nil node used to make lists of child nodes?"""

        raise NotImplementedError


    def addChild(self, t, child):
        """
        Add a child to the tree t.  If child is a flat tree (a list), make all
        in list children of t.  Warning: if t has no children, but child does
        and child isNil then you can decide it is ok to move children to t via
        t.children = child.children; i.e., without copying the array.  Just
        make sure that this is consistent with have the user will build
        ASTs.
        """

        raise NotImplementedError


    def becomeRoot(self, newRoot, oldRoot):
        """
        If oldRoot is a nil root, just copy or move the children to newRoot.
        If not a nil root, make oldRoot a child of newRoot.
        
           old=^(nil a b c), new=r yields ^(r a b c)
           old=^(a b c), new=r yields ^(r ^(a b c))

        If newRoot is a nil-rooted single child tree, use the single
        child as the new root node.

           old=^(nil a b c), new=^(nil r) yields ^(r a b c)
           old=^(a b c), new=^(nil r) yields ^(r ^(a b c))

        If oldRoot was null, it's ok, just return newRoot (even if isNil).

           old=null, new=r yields r
           old=null, new=^(nil r) yields ^(nil r)

        Return newRoot.  Throw an exception if newRoot is not a
        simple node or nil root with a single child node--it must be a root
        node.  If newRoot is ^(nil x) return x as newRoot.

        Be advised that it's ok for newRoot to point at oldRoot's
        children; i.e., you don't have to copy the list.  We are
        constructing these nodes so we should have this control for
        efficiency.
        """

        raise NotImplementedError


    def rulePostProcessing(self, root):
        """
        Given the root of the subtree created for this rule, post process
        it to do any simplifications or whatever you want.  A required
        behavior is to convert ^(nil singleSubtree) to singleSubtree
        as the setting of start/stop indexes relies on a single non-nil root
        for non-flat trees.

        Flat trees such as for lists like "idlist : ID+ ;" are left alone
        unless there is only one ID.  For a list, the start/stop indexes
        are set in the nil node.

        This method is executed after all rule tree construction and right
        before setTokenBoundaries().
        """

        raise NotImplementedError


    def getUniqueID(self, node):
        """For identifying trees.

        How to identify nodes so we can say "add node to a prior node"?
        Even becomeRoot is an issue.  Use System.identityHashCode(node)
        usually.
        """

        raise NotImplementedError


    # R e w r i t e  R u l e s

    def createFromToken(self, tokenType, fromToken, text=None):
        """
        Create a new node derived from a token, with a new token type and
        (optionally) new text.

        This is invoked from an imaginary node ref on right side of a
        rewrite rule as IMAG[$tokenLabel] or IMAG[$tokenLabel "IMAG"].

        This should invoke createToken(Token).
        """

        raise NotImplementedError


    def createFromType(self, tokenType, text):
        """Create a new node derived from a token, with a new token type.

        This is invoked from an imaginary node ref on right side of a
        rewrite rule as IMAG["IMAG"].

        This should invoke createToken(int,String).
        """

        raise NotImplementedError


    # C o n t e n t

    def getType(self, t):
        """For tree parsing, I need to know the token type of a node"""

        raise NotImplementedError


    def setType(self, t, type):
        """Node constructors can set the type of a node"""

        raise NotImplementedError


    def getText(self, t):
        raise NotImplementedError

    def setText(self, t, text):
        """Node constructors can set the text of a node"""

        raise NotImplementedError


    def getToken(self, t):
        """Return the token object from which this node was created.

        Currently used only for printing an error message.
        The error display routine in BaseRecognizer needs to
        display where the input the error occurred. If your
        tree of limitation does not store information that can
        lead you to the token, you can create a token filled with
        the appropriate information and pass that back.  See
        BaseRecognizer.getErrorMessage().
        """

        raise NotImplementedError


    def setTokenBoundaries(self, t, startToken, stopToken):
        """
        Where are the bounds in the input token stream for this node and
        all children?  Each rule that creates AST nodes will call this
        method right before returning.  Flat trees (i.e., lists) will
        still usually have a nil root node just to hold the children list.
        That node would contain the start/stop indexes then.
        """

        raise NotImplementedError


    def getTokenStartIndex(self, t):
        """
        Get the token start index for this subtree; return -1 if no such index
        """

        raise NotImplementedError

        
    def getTokenStopIndex(self, t):
        """
        Get the token stop index for this subtree; return -1 if no such index
        """

        raise NotImplementedError
        

    # N a v i g a t i o n  /  T r e e  P a r s i n g

    def getChild(self, t, i):
        """Get a child 0..n-1 node"""

        raise NotImplementedError


    def getChildCount(self, t):
        """How many children?  If 0, then this is a leaf node"""

        raise NotImplementedError


    # Misc

    def create(self, *args):
        """
        Deprecated, use createWithPayload, createFromToken or createFromType.

        This method only exists to mimic the Java interface of TreeAdaptor.
        
        """

        if len(args) == 1 and isinstance(args[0], Token):
            # Object create(Token payload);
            warnings.warn(
                "Using create() is deprecated, use createWithPayload()",
                DeprecationWarning,
                stacklevel=2
                )
            return self.createWithPayload(args[0])

        if (len(args) == 2
            and isinstance(args[0], (int, long))
            and isinstance(args[1], Token)
            ):
            # Object create(int tokenType, Token fromToken);
            warnings.warn(
                "Using create() is deprecated, use createFromToken()",
                DeprecationWarning,
                stacklevel=2
                )
            return self.createFromToken(args[0], args[1])

        if (len(args) == 3
            and isinstance(args[0], (int, long))
            and isinstance(args[1], Token)
            and isinstance(args[2], basestring)
            ):
            # Object create(int tokenType, Token fromToken, String text);
            warnings.warn(
                "Using create() is deprecated, use createFromToken()",
                DeprecationWarning,
                stacklevel=2
                )
            return self.createFromToken(args[0], args[1], args[2])

        if (len(args) == 2
            and isinstance(args[0], (int, long))
            and isinstance(args[1], basestring)
            ):
            # Object create(int tokenType, String text);
            warnings.warn(
                "Using create() is deprecated, use createFromType()",
                DeprecationWarning,