| /* |
| [The "BSD license"] |
| Copyright (c) 2005-2009 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. |
| */ |
| package org.antlr.runtime.tree; |
| |
| import org.antlr.runtime.Token; |
| import org.antlr.runtime.TokenStream; |
| import org.antlr.runtime.RecognitionException; |
| |
| /** 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. :( |
| */ |
| public interface TreeAdaptor { |
| // C o n s t r u c t i o n |
| |
| /** 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. |
| */ |
| public Object create(Token payload); |
| |
| /** Duplicate a single tree node. |
| * Override if you want another kind of node to be built. |
| */ |
| public Object dupNode(Object treeNode); |
| |
| /** Duplicate tree recursively, using dupNode() for each node */ |
| public Object dupTree(Object tree); |
| |
| /** 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);" |
| */ |
| public Object nil(); |
| |
| /** 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. |
| */ |
| public Object errorNode(TokenStream input, Token start, Token stop, RecognitionException e); |
| |
| /** Is tree considered a nil node used to make lists of child nodes? */ |
| public boolean isNil(Object tree); |
| |
| /** 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. |
| */ |
| public void addChild(Object t, Object child); |
| |
| /** 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. |
| */ |
| public Object becomeRoot(Object newRoot, Object oldRoot); |
| |
| /** 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(). |
| */ |
| public Object rulePostProcessing(Object root); |
| |
| /** 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. |
| */ |
| public int getUniqueID(Object node); |
| |
| |
| // R e w r i t e R u l e s |
| |
| /** 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. |
| */ |
| public Object becomeRoot(Token newRoot, Object oldRoot); |
| |
| /** 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[$tokenLabel]. |
| * |
| * This should invoke createToken(Token). |
| */ |
| public Object create(int tokenType, Token fromToken); |
| |
| /** Same as create(tokenType,fromToken) except set the text too. |
| * This is invoked from an imaginary node ref on right side of a |
| * rewrite rule as IMAG[$tokenLabel, "IMAG"]. |
| * |
| * This should invoke createToken(Token). |
| */ |
| public Object create(int tokenType, Token fromToken, String 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). |
| */ |
| public Object create(int tokenType, String text); |
| |
| |
| // C o n t e n t |
| |
| /** For tree parsing, I need to know the token type of a node */ |
| public int getType(Object t); |
| |
| /** Node constructors can set the type of a node */ |
| public void setType(Object t, int type); |
| |
| public String getText(Object t); |
| |
| /** Node constructors can set the text of a node */ |
| public void setText(Object t, String text); |
| |
| /** 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(). |
| */ |
| public Token getToken(Object t); |
| |
| /** 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. |
| */ |
| public void setTokenBoundaries(Object t, Token startToken, Token stopToken); |
| |
| /** Get the token start index for this subtree; return -1 if no such index */ |
| public int getTokenStartIndex(Object t); |
| |
| /** Get the token stop index for this subtree; return -1 if no such index */ |
| public int getTokenStopIndex(Object t); |
| |
| |
| // N a v i g a t i o n / T r e e P a r s i n g |
| |
| /** Get a child 0..n-1 node */ |
| public Object getChild(Object t, int i); |
| |
| /** Set ith child (0..n-1) to t; t must be non-null and non-nil node */ |
| public void setChild(Object t, int i, Object child); |
| |
| /** Remove ith child and shift children down from right. */ |
| public Object deleteChild(Object t, int i); |
| |
| /** How many children? If 0, then this is a leaf node */ |
| public int getChildCount(Object t); |
| |
| /** 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. |
| */ |
| public Object getParent(Object t); |
| public void setParent(Object t, Object parent); |
| |
| /** 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. |
| */ |
| public int getChildIndex(Object t); |
| public void setChildIndex(Object t, int index); |
| |
| /** 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. |
| */ |
| public void replaceChildren(Object parent, int startChildIndex, int stopChildIndex, Object t); |
| } |