org.antlr.v4.runtime.RuleContext Maven / Gradle / Ivy
/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* 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
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.v4.runtime;
import org.antlr.v4.runtime.misc.Interval;
import org.antlr.v4.runtime.misc.Nullable;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.ParseTreeVisitor;
import org.antlr.v4.runtime.tree.RuleNode;
import org.antlr.v4.runtime.tree.Trees;
import org.antlr.v4.runtime.tree.gui.TreeViewer;
import javax.print.PrintException;
import javax.swing.JDialog;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Future;
/** A rule context is a record of a single rule invocation. It knows
* which context invoked it, if any. If there is no parent context, then
* naturally the invoking state is not valid. The parent link
* provides a chain upwards from the current rule invocation to the root
* of the invocation tree, forming a stack. We actually carry no
* information about the rule associated with this context (except
* when parsing). We keep only the state number of the invoking state from
* the ATN submachine that invoked this. Contrast this with the s
* pointer inside ParserRuleContext that tracks the current state
* being "executed" for the current rule.
*
* The parent contexts are useful for computing lookahead sets and
* getting error information.
*
* These objects are used during parsing and prediction.
* For the special case of parsers and tree parsers, we use the subclass
* ParserRuleContext.
*
* @see ParserRuleContext
*/
public class RuleContext implements RuleNode {
public static final ParserRuleContext EMPTY = new ParserRuleContext();
/** What context invoked this rule? */
public RuleContext parent;
/** What state invoked the rule associated with this context?
* The "return address" is the followState of invokingState
* If parent is null, this should be -1.
*/
public int invokingState = -1;
public RuleContext() {}
public RuleContext(RuleContext parent, int invokingState) {
this.parent = parent;
//if ( parent!=null ) System.out.println("invoke "+stateNumber+" from "+parent);
this.invokingState = invokingState;
}
public int depth() {
int n = 0;
RuleContext p = this;
while ( p!=null ) {
p = p.parent;
n++;
}
return n;
}
/** A context is empty if there is no invoking state; meaning nobody call
* current context.
*/
public boolean isEmpty() {
return invokingState == -1;
}
// satisfy the ParseTree / SyntaxTree interface
@Override
public Interval getSourceInterval() {
return Interval.INVALID;
}
@Override
public RuleContext getRuleContext() { return this; }
@Override
public RuleContext getParent() { return parent; }
@Override
public RuleContext getPayload() { return this; }
/** Return the combined text of all child nodes. This method only considers
* tokens which have been added to the parse tree.
*
* Since tokens on hidden channels (e.g. whitespace or comments) are not
* added to the parse trees, they will not appear in the output of this
* method.
*/
@Override
public String getText() {
if (getChildCount() == 0) {
return "";
}
StringBuilder builder = new StringBuilder();
for (int i = 0; i < getChildCount(); i++) {
builder.append(getChild(i).getText());
}
return builder.toString();
}
public int getRuleIndex() { return -1; }
@Override
public ParseTree getChild(int i) {
return null;
}
@Override
public int getChildCount() {
return 0;
}
@Override
public T accept(ParseTreeVisitor visitor) { return visitor.visitChildren(this); }
/** Call this method to view a parse tree in a dialog box visually. */
public Future inspect(@Nullable Parser parser) {
List ruleNames = parser != null ? Arrays.asList(parser.getRuleNames()) : null;
return inspect(ruleNames);
}
public Future inspect(@Nullable List ruleNames) {
TreeViewer viewer = new TreeViewer(ruleNames, this);
return viewer.open();
}
/** Save this tree in a postscript file */
public void save(@Nullable Parser parser, String fileName)
throws IOException, PrintException
{
List ruleNames = parser != null ? Arrays.asList(parser.getRuleNames()) : null;
save(ruleNames, fileName);
}
/** Save this tree in a postscript file using a particular font name and size */
public void save(@Nullable Parser parser, String fileName,
String fontName, int fontSize)
throws IOException
{
List ruleNames = parser != null ? Arrays.asList(parser.getRuleNames()) : null;
save(ruleNames, fileName, fontName, fontSize);
}
/** Save this tree in a postscript file */
public void save(@Nullable List ruleNames, String fileName)
throws IOException, PrintException
{
Trees.writePS(this, ruleNames, fileName);
}
/** Save this tree in a postscript file using a particular font name and size */
public void save(@Nullable List ruleNames, String fileName,
String fontName, int fontSize)
throws IOException
{
Trees.writePS(this, ruleNames, fileName, fontName, fontSize);
}
/** Print out a whole tree, not just a node, in LISP format
* (root child1 .. childN). Print just a node if this is a leaf.
* We have to know the recognizer so we can get rule names.
*/
@Override
public String toStringTree(@Nullable Parser recog) {
return Trees.toStringTree(this, recog);
}
/** Print out a whole tree, not just a node, in LISP format
* (root child1 .. childN). Print just a node if this is a leaf.
*/
public String toStringTree(@Nullable List ruleNames) {
return Trees.toStringTree(this, ruleNames);
}
@Override
public String toStringTree() {
return toStringTree((List)null);
}
@Override
public String toString() {
return toString((List)null, (RuleContext)null);
}
public final String toString(@Nullable Recognizer recog) {
return toString(recog, ParserRuleContext.EMPTY);
}
public final String toString(@Nullable List ruleNames) {
return toString(ruleNames, null);
}
// recog null unless ParserRuleContext, in which case we use subclass toString(...)
public String toString(@Nullable Recognizer recog, @Nullable RuleContext stop) {
String[] ruleNames = recog != null ? recog.getRuleNames() : null;
List ruleNamesList = ruleNames != null ? Arrays.asList(ruleNames) : null;
return toString(ruleNamesList, stop);
}
public String toString(@Nullable List ruleNames, @Nullable RuleContext stop) {
StringBuilder buf = new StringBuilder();
RuleContext p = this;
buf.append("[");
while (p != null && p != stop) {
if (ruleNames == null) {
if (!p.isEmpty()) {
buf.append(p.invokingState);
}
}
else {
int ruleIndex = p.getRuleIndex();
String ruleName = ruleIndex >= 0 && ruleIndex < ruleNames.size() ? ruleNames.get(ruleIndex) : Integer.toString(ruleIndex);
buf.append(ruleName);
}
if (p.parent != null && (ruleNames != null || !p.parent.isEmpty())) {
buf.append(" ");
}
p = p.parent;
}
buf.append("]");
return buf.toString();
}
}