Package org.antlr.runtime.debug

Class DebugTreeAdaptor

  • All Implemented Interfaces:
    TreeAdaptor
    public class DebugTreeAdaptor
extends Object
implements TreeAdaptor
    A TreeAdaptor proxy that fires debugging events to a DebugEventListener delegate and uses the TreeAdaptor delegate to do the actual work. All AST events are triggered by this adaptor; no code gen changes are needed in generated rules. Debugging events are triggered *after* invoking tree adaptor routines. Trees created with actions in rewrite actions like "-> ^(ADD {foo} {bar})" cannot be tracked as they might not use the adaptor to create foo, bar. The debug listener has to deal with tree node IDs for which it did not see a createNode event. A single <unknown> node is sufficient even if it represents a whole tree.

    • Method Detail

      • create

        public Object create​(Token payload)
        Description copied from interface: TreeAdaptor
        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. Override if you want another kind of node to be built.
        Specified by:
        create in interface TreeAdaptor

      • errorNode

        public Object errorNode​(TokenStream input,
                        Token start,
                        Token stop,
                        RecognitionException e)
        Description copied from interface: TreeAdaptor
        Return a tree node representing an error. This node records the tokens consumed during error recovery. The start token indicates the input symbol at which the error was detected. The stop token indicates the last symbol consumed during recovery. You must specify the input stream so that the erroneous text can be packaged up in the error node. The exception could be useful to some applications; default implementation stores ptr to it in the CommonErrorNode. This only makes sense during token parsing, not tree parsing. Tree parsing should happen only when parsing and tree construction succeed.
        Specified by:
        errorNode 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

      • simulateTreeConstruction

        protected void simulateTreeConstruction​(Object t)
        ^(A B C): emit create A, create B, add child, ...

      • dupNode

        public Object dupNode​(Object treeNode)
        Description copied from interface: TreeAdaptor
        Duplicate a single tree node. Override if you want another kind of node to be built.
        Specified by:
        dupNode in interface TreeAdaptor

      • 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

      • 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

      • addChild

        public void addChild​(Object t,
                     Object child)
        Description copied from interface: TreeAdaptor
        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. Do nothing if t or child is null.
        Specified by:
        addChild in interface TreeAdaptor

      • becomeRoot

        public Object becomeRoot​(Object newRoot,
                         Object oldRoot)
        Description copied from interface: TreeAdaptor
        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

      • rulePostProcessing

        public Object rulePostProcessing​(Object root)
        Description copied from interface: TreeAdaptor
        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().
        Specified by:
        rulePostProcessing in interface TreeAdaptor

      • addChild

        public void addChild​(Object t,
                     Token child)

      • 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

      • getToken

        public Token getToken​(Object t)
        Description copied from interface: TreeAdaptor
        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().
        Specified by:
        getToken in interface TreeAdaptor

      • setTokenBoundaries

        public void setTokenBoundaries​(Object t,
                               Token startToken,
                               Token stopToken)
        Description copied from interface: TreeAdaptor
        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.
        Specified by:
        setTokenBoundaries in interface TreeAdaptor

      • getTokenStartIndex

        public int getTokenStartIndex​(Object t)
        Description copied from interface: TreeAdaptor
        Get the token start index for this subtree; return -1 if no such index
        Specified by:
        getTokenStartIndex in interface TreeAdaptor

      • getTokenStopIndex

        public int getTokenStopIndex​(Object t)
        Description copied from interface: TreeAdaptor
        Get the token stop index for this subtree; return -1 if no such index
        Specified by:
        getTokenStopIndex 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

      • getParent

        public Object getParent​(Object t)
        Description copied from interface: TreeAdaptor
        Who is the parent node of this node; if null, implies node is root. If your node type doesn't handle this, it's ok but the tree rewrites in tree parsers need this functionality.
        Specified by:
        getParent in interface TreeAdaptor

      • getChildIndex

        public int getChildIndex​(Object t)
        Description copied from interface: TreeAdaptor
        What index is this node in the child list? Range: 0..n-1 If your node type doesn't handle this, it's ok but the tree rewrites in tree parsers need this functionality.
        Specified by:
        getChildIndex in interface TreeAdaptor

      • replaceChildren

        public void replaceChildren​(Object parent,
                            int startChildIndex,
                            int stopChildIndex,
                            Object t)
        Description copied from interface: TreeAdaptor
        Replace from start to stop child index of parent with t, which might be a list. Number of children may be different after this call. If parent is null, don't do anything; must be at root of overall tree. Can't replace whatever points to the parent externally. Do nothing.
        Specified by:
        replaceChildren in interface TreeAdaptor