Package org.antlr.runtime.tree

Class BaseTreeAdaptor

    • Field Detail

      • treeToUniqueIDMap

        protected Map<Object,​Integer> treeToUniqueIDMap
        System.identityHashCode() is not always unique; we have to track ourselves. That's ok, it's only for debugging, though it's expensive: we have to create a hashtable with all tree nodes in it.

      • uniqueNodeID

        protected int uniqueNodeID

    • Constructor Detail

      • BaseTreeAdaptor

        public BaseTreeAdaptor()

    • Method Detail

      • nil

        public Object nil()
        Description copied from interface: TreeAdaptor
        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);"
        Specified by:
        nil in interface TreeAdaptor

      • errorNode

        public Object errorNode​(TokenStream input,
                        Token start,
                        Token stop,
                        RecognitionException e)
        create tree node that holds the start and stop tokens associated with an error. If you specify your own kind of tree nodes, you will likely have to override this method. CommonTree returns Token.INVALID_TOKEN_TYPE if no token payload but you might have to set token type for diff node type. You don't have to subclass CommonErrorNode; you will likely need to subclass your own tree node class to avoid class cast exception.
        Specified by:
        errorNode in interface TreeAdaptor

      • isNil

        public boolean isNil​(Object tree)
        Description copied from interface: TreeAdaptor
        Is tree considered a nil node used to make lists of child nodes?
        Specified by:
        isNil in interface TreeAdaptor

      • dupTree

        public Object dupTree​(Object tree)
        Description copied from interface: TreeAdaptor
        Duplicate tree recursively, using dupNode() for each node
        Specified by:
        dupTree in interface TreeAdaptor

      • dupTree

        public Object dupTree​(Object t,
                      Object parent)
        This is generic in the sense that it will work with any kind of tree (not just Tree interface). It invokes the adaptor routines not the tree node routines to do the construction.

      • addChild

        public void addChild​(Object t,
                     Object 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.
        Specified by:
        addChild in interface TreeAdaptor

      • becomeRoot

        public Object becomeRoot​(Object newRoot,
                         Object 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.
        Specified by:
        becomeRoot in interface TreeAdaptor

      • becomeRoot

        public Object becomeRoot​(Token newRoot,
                         Object oldRoot)
        Description copied from interface: TreeAdaptor
        Create a node for newRoot make it the root of 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. Return node created for newRoot. Be advised: when debugging ASTs, the DebugTreeAdaptor manually calls create(Token child) and then plain becomeRoot(node, node) because it needs to trap calls to create, but it can't since it delegates to not inherits from the TreeAdaptor.
        Specified by:
        becomeRoot in interface TreeAdaptor

      • create

        public Object create​(int tokenType,
                     Token fromToken)
        Description copied from interface: TreeAdaptor
        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[$tokenLabel]. This should invoke createToken(Token).
        Specified by:
        create in interface TreeAdaptor

      • create

        public Object create​(int tokenType,
                     Token fromToken,
                     String text)
        Description copied from interface: TreeAdaptor
        Same as create(tokenType,fromToken) except set the text too. This is invoked from an imaginary node ref on right side of a rewrite rule as IMAG[$tokenLabel, "IMAG"]. This should invoke createToken(Token).
        Specified by:
        create in interface TreeAdaptor

      • create

        public Object create​(int tokenType,
                     String text)
        Description copied from interface: TreeAdaptor
        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).
        Specified by:
        create in interface TreeAdaptor

      • getType

        public int getType​(Object t)
        Description copied from interface: TreeAdaptor
        For tree parsing, I need to know the token type of a node
        Specified by:
        getType in interface TreeAdaptor

      • setType

        public void setType​(Object t,
                    int type)
        Description copied from interface: TreeAdaptor
        Node constructors can set the type of a node
        Specified by:
        setType in interface TreeAdaptor

      • setChild

        public void setChild​(Object t,
                     int i,
                     Object child)
        Description copied from interface: TreeAdaptor
        Set ith child (0..n-1) to t; t must be non-null and non-nil node
        Specified by:
        setChild in interface TreeAdaptor

      • getChildCount

        public int getChildCount​(Object t)
        Description copied from interface: TreeAdaptor
        How many children? If 0, then this is a leaf node
        Specified by:
        getChildCount in interface TreeAdaptor

      • getUniqueID

        public int getUniqueID​(Object node)
        Description copied from interface: TreeAdaptor
        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.
        Specified by:
        getUniqueID in interface TreeAdaptor

      • createToken

        public abstract Token createToken​(int tokenType,
                                  String text)
        Tell me how to create a token for use with imaginary token nodes. For example, there is probably no input symbol associated with imaginary token DECL, but you need to create it as a payload or whatever for the DECL node as in ^(DECL type ID). If you care what the token payload objects' type is, you should override this method and any other createToken variant.

      • createToken

        public abstract Token createToken​(Token fromToken)
        Tell me how to create a token for use with imaginary token nodes. For example, there is probably no input symbol associated with imaginary token DECL, but you need to create it as a payload or whatever for the DECL node as in ^(DECL type ID). This is a variant of createToken where the new token is derived from an actual real input token. Typically this is for converting '{' tokens to BLOCK etc... You'll see r : lc='{' ID+ '}' -> ^(BLOCK[$lc] ID+) ; If you care what the token payload objects' type is, you should override this method and any other createToken variant.