/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.runtime.atn;

import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.Lexer;

Represents a single action which can be executed following the successful
match of a lexer rule. Lexer actions are used for both embedded action syntax
and ANTLR 4's new lexer command syntax.
Author:
Sam Harwell
Since:
4.2/**
 * Represents a single action which can be executed following the successful
 * match of a lexer rule. Lexer actions are used for both embedded action syntax
 * and ANTLR 4's new lexer command syntax.
 *
 * @author Sam Harwell
 * @since 4.2
 */
public interface LexerAction {
	
Gets the serialization type of the lexer action.
Returns:
The serialization type of the lexer action./**
	 * Gets the serialization type of the lexer action.
	 *
	 * @return The serialization type of the lexer action.
	 */
	LexerActionType getActionType();

	
Gets whether the lexer action is position-dependent. Position-dependent actions may have different semantics depending on the CharStream index at the time the action is executed. 
Many lexer commands, including type, skip, and more, do not check the input index during their execution. Actions like this are position-independent, and may be stored more efficiently as part of the LexerATNConfig.lexerActionExecutor.
Returns:
true if the lexer action semantics can be affected by the position of the input CharStream at the time it is executed; otherwise, false./**
	 * Gets whether the lexer action is position-dependent. Position-dependent
	 * actions may have different semantics depending on the {@link CharStream}
	 * index at the time the action is executed.
	 *
	 * <p>Many lexer commands, including {@code type}, {@code skip}, and
	 * {@code more}, do not check the input index during their execution.
	 * Actions like this are position-independent, and may be stored more
	 * efficiently as part of the {@link LexerATNConfig#lexerActionExecutor}.</p>
	 *
	 * @return {@code true} if the lexer action semantics can be affected by the
	 * position of the input {@link CharStream} at the time it is executed;
	 * otherwise, {@code false}.
	 */
	boolean isPositionDependent();

	
Execute the lexer action in the context of the specified Lexer. 
For position-dependent actions, the input stream must already be
positioned correctly prior to calling this method.
Params:
lexer – The lexer instance./**
	 * Execute the lexer action in the context of the specified {@link Lexer}.
	 *
	 * <p>For position-dependent actions, the input stream must already be
	 * positioned correctly prior to calling this method.</p>
	 *
	 * @param lexer The lexer instance.
	 */
	void execute(Lexer lexer);
}