commonMain.org.antlr.v4.kotlinruntime.atn.LexerAction.kt Maven / Gradle / Ivy
// Copyright 2017-present Strumenta and contributors, licensed under Apache 2.0.
// Copyright 2024-present Strumenta and contributors, licensed under BSD 3-Clause.
package org.antlr.v4.kotlinruntime.atn
import org.antlr.v4.kotlinruntime.CharStream
import org.antlr.v4.kotlinruntime.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
*/
public interface LexerAction {
/**
* The serialization type of the lexer action.
*/
public val actionType: LexerActionType
/**
* 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].
*
* @return `true` if the lexer action semantics can be affected by the
* position of the input [CharStream] at the time it is executed,
* otherwise `false`
*/
public val isPositionDependent: Boolean
/**
* 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.
*
* @param lexer The lexer instance
*/
public fun execute(lexer: Lexer)
}