Package org.antlr.v4.runtime.atn

Class LexerCustomAction

java.lang.Object

org.antlr.v4.runtime.atn.LexerCustomAction

All Implemented Interfaces:

LexerAction

public final class LexerCustomAction
extends Object
implements LexerAction

Executes a custom lexer action by calling Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int) with the rule and action indexes assigned to the custom action. The implementation of a custom action is added to the generated code for the lexer in an override of Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int) when the grammar is compiled.

This class may represent embedded actions created with the {...} syntax in ANTLR 4, as well as actions created for lexer commands where the command argument could not be evaluated when the grammar was compiled.

Since:

4.2

Author:

Sam Harwell

Constructor Summary

Constructors

Constructor	Description
LexerCustomAction(int ruleIndex, int actionIndex)	Constructs a custom lexer action with the specified rule and action indexes.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
void	execute(Lexer lexer)	Execute the lexer action in the context of the specified Lexer.
int	getActionIndex()	Gets the action index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).
LexerActionType	getActionType()	Gets the serialization type of the lexer action.
int	getRuleIndex()	Gets the rule index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).
int	hashCode()
boolean	isPositionDependent()	Gets whether the lexer action is position-dependent.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LexerCustomAction

public LexerCustomAction(int ruleIndex,
                         int actionIndex)

Constructs a custom lexer action with the specified rule and action indexes.

Parameters:

ruleIndex - The rule index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).

actionIndex - The action index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).

Method Detail

getRuleIndex

public int getRuleIndex()

Gets the rule index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).

Returns:

The rule index for the custom action.

getActionIndex

public int getActionIndex()

Gets the action index to use for calls to Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int).

Returns:

The action index for the custom action.

getActionType

public LexerActionType getActionType()

Gets the serialization type of the lexer action.

Specified by:

getActionType in interface LexerAction

Returns:

This method returns LexerActionType.CUSTOM.

isPositionDependent

public boolean isPositionDependent()

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.

Custom actions are position-dependent since they may represent a user-defined embedded action which makes calls to methods like Lexer.getText().

Specified by:

isPositionDependent in interface LexerAction

Returns:

This method returns true.

execute

public void execute(Lexer lexer)

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.

Custom actions are implemented by calling Recognizer.action(org.antlr.v4.runtime.RuleContext, int, int) with the appropriate rule and action indexes.

Specified by:

execute in interface LexerAction

Parameters:

lexer - The lexer instance.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object