org.antlr.runtime.tree
Class BaseTreeAdaptor

java.lang.Object
  org.antlr.runtime.tree.BaseTreeAdaptor

All Implemented Interfaces:

TreeAdaptor

Direct Known Subclasses:

CommonTreeAdaptor

public abstract class BaseTreeAdaptor
extends Object
implements TreeAdaptor

A TreeAdaptor that works with any Tree implementation.

Field Summary

protected Map	treeToUniqueIDMap System.identityHashCode() is not always unique; we have to track ourselves.
protected int	uniqueNodeID

Constructor Summary

BaseTreeAdaptor()

Method Summary

void	addChild(Object t, Object child) Add a child to the tree t.
Object	becomeRoot(Object newRoot, Object oldRoot) If oldRoot is a nil root, just copy or move the children to newRoot.
Object	becomeRoot(Token newRoot, Object oldRoot) Create a node for newRoot make it the root of oldRoot.
Object	create(int tokenType, String text) Create a new node derived from a token, with a new token type.
Object	create(int tokenType, Token fromToken) Create a new node derived from a token, with a new token type.
Object	create(int tokenType, Token fromToken, String text) Same as create(tokenType,fromToken) except set the text too.
abstract Token	createToken(int tokenType, String text) Tell me how to create a token for use with imaginary token nodes.
abstract Token	createToken(Token fromToken) Tell me how to create a token for use with imaginary token nodes.
Object	deleteChild(Object t, int i) Remove ith child and shift children down from right.
Object	dupTree(Object tree) Duplicate tree recursively, using dupNode() for each node
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).
Object	errorNode(TokenStream input, Token start, Token stop, RecognitionException e) create tree node that holds the start and stop tokens associated with an error.
Object	getChild(Object t, int i) Get a child 0..n-1 node
int	getChildCount(Object t) How many children? If 0, then this is a leaf node
String	getText(Object t)
int	getType(Object t) For tree parsing, I need to know the token type of a node
int	getUniqueID(Object node) For identifying trees.
boolean	isNil(Object tree) Is tree considered a nil node used to make lists of child nodes?
Object	nil() Return a nil node (an empty but non-null node) that can hold a list of element as the children.
Object	rulePostProcessing(Object root) Transform ^(nil x) to x and nil to null
void	setChild(Object t, int i, Object child) Set ith child (0..n-1) to t; t must be non-null and non-nil node
void	setText(Object t, String text) Node constructors can set the text of a node
void	setType(Object t, int type) Node constructors can set the type of a node

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.antlr.runtime.tree.TreeAdaptor

create, dupNode, getChildIndex, getParent, getToken, getTokenStartIndex, getTokenStopIndex, replaceChildren, setChildIndex, setParent, setTokenBoundaries

Field Detail

treeToUniqueIDMap

protected Map 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

rulePostProcessing

public Object rulePostProcessing(Object root)

Transform ^(nil x) to x and nil to null

Specified by:

rulePostProcessing 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

getText

public String getText(Object t)

Specified by:

getText in interface TreeAdaptor

setText

public void setText(Object t,
                    String text)

Description copied from interface: TreeAdaptor

Node constructors can set the text of a node

Specified by:

setText in interface TreeAdaptor

getChild

public Object getChild(Object t,
                       int i)

Description copied from interface: TreeAdaptor

Get a child 0..n-1 node

Specified by:

getChild 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

deleteChild

public Object deleteChild(Object t,
                          int i)

Description copied from interface: TreeAdaptor

Remove ith child and shift children down from right.

Specified by:

deleteChild 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.