| /* |
| [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.IntStream; |
| import org.antlr.runtime.Token; |
| import org.antlr.runtime.TokenStream; |
| |
| /** A stream of tree nodes, accessing nodes from a tree of some kind */ |
| public interface TreeNodeStream extends IntStream { |
| /** Get a tree node at an absolute index {@code i}; 0..n-1. |
| * If you don't want to buffer up nodes, then this method makes no |
| * sense for you. |
| */ |
| public Object get(int i); |
| |
| /** |
| * Get tree node at current input pointer + {@code k} ahead where |
| * {@code k==1} is next node. {@code k<0} indicates nodes in the past. So |
| * {@code LT(-1)} is previous node, but implementations are not required to |
| * provide results for {@code k < -1}. {@code LT(0)} is undefined. For |
| * {@code k<=n}, return {@code null}. Return {@code null} for {@code LT(0)} |
| * and any index that results in an absolute address that is negative. |
| * <p> |
| * This is analogous to {@link TokenStream#LT}, but this returns a tree node |
| * instead of a {@link Token}. Makes code generation identical for both |
| * parser and tree grammars.</p> |
| */ |
| public Object LT(int k); |
| |
| /** Where is this stream pulling nodes from? This is not the name, but |
| * the object that provides node objects. |
| */ |
| public Object getTreeSource(); |
| |
| /** |
| * If the tree associated with this stream was created from a |
| * {@link TokenStream}, you can specify it here. Used to do rule |
| * {@code $text} attribute in tree parser. Optional unless you use tree |
| * parser rule {@code $text} attribute or {@code output=template} and |
| * {@code rewrite=true} options. |
| */ |
| public TokenStream getTokenStream(); |
| |
| /** What adaptor can tell me how to interpret/navigate nodes and |
| * trees. E.g., get text of a node. |
| */ |
| public TreeAdaptor getTreeAdaptor(); |
| |
| /** |
| * As we flatten the tree, we use {@link Token#UP}, {@link Token#DOWN} nodes |
| * to represent the tree structure. When debugging we need unique nodes so |
| * we have to instantiate new ones. When doing normal tree parsing, it's |
| * slow and a waste of memory to create unique navigation nodes. Default |
| * should be {@code false}. |
| */ |
| public void setUniqueNavigationNodes(boolean uniqueNavigationNodes); |
| |
| /** Reset the tree node stream in such a way that it acts like |
| * a freshly constructed stream. |
| */ |
| public void reset(); |
| |
| /** |
| * Return the text of all nodes from {@code start} to {@code stop}, |
| * inclusive. If the stream does not buffer all the nodes then it can still |
| * walk recursively from start until stop. You can always return |
| * {@code null} or {@code ""} too, but users should not access |
| * {@code $ruleLabel.text} in an action of course in that case. |
| */ |
| public String toString(Object start, Object stop); |
| |
| // REWRITING TREES (used by tree parser) |
| |
| /** |
| * Replace children of {@code parent} from index {@code startChildIndex} to |
| * {@code stopChildIndex} with {@code t}, which might be a list. Number of |
| * children may be different after this call. The stream is notified because |
| * it is walking the tree and might need to know you are monkeying with the |
| * underlying tree. Also, it might be able to modify the node stream to |
| * avoid restreaming for future phases. |
| * <p> |
| * If {@code parent} is {@code null}, don't do anything; must be at root of |
| * overall tree. Can't replace whatever points to the parent externally. Do |
| * nothing.</p> |
| */ |
| public void replaceChildren(Object parent, int startChildIndex, int stopChildIndex, Object t); |
| } |