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update comments from Sam's version

This commit is contained in:
Terence Parr 2012-09-06 14:17:13 -07:00
parent 2d324058d6
commit 2b5c3723ba
1 changed files with 22 additions and 1 deletions
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23
runtime/Java/src/org/antlr/v4/runtime/tree/ParseTreeVisitor.java
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@ -3,9 +3,19 @@ package org.antlr.v4.runtime.tree;
import org.antlr.v4.runtime.ParserRuleContext;
import org.antlr.v4.runtime.Token;
/** {@code T} is return type of {@code visit} methods. Use {@link Void} for no return type.
/** This class defines the basic notion of a parse tree visitor
* object. Generated visitors extend this class and implement the XVisitor
* interface for grammar X.
*
* @param <T> The return type of the visit operation. Use {@link Void} for
* operations with no return type.
*/
public class ParseTreeVisitor<T> {
/** Visit a parse tree, and return a user-defined result of the operation.
*
* @param tree The {@link ParseTree} to visit.
* @return The result of visiting the parse tree.
*/
public T visit(ParseTree tree) {
return tree.accept(this);
}
@ -27,6 +37,17 @@ public class ParseTreeVisitor<T> {
return result;
}
/** Visit a terminal node, and return a user-defined result of the operation.
*
* @param node The {@link TerminalNode} to visit.
* @return The result of visiting the node.
*/
public T visitTerminal(TerminalNode<? extends Token> node) { return null; }
/** Visit an error node, and return a user-defined result of the operation.
*
* @param node The {@link ErrorNode} to visit.
* @return The result of visiting the node.
*/
public T visitErrorNode(ErrorNode<? extends Token> node) { return null; }
}