org.graalvm.shadowed.org.antlr.v4.runtime.atn

Class SemanticContext.Empty

java.lang.Object

org.graalvm.shadowed.org.antlr.v4.runtime.atn.SemanticContext

org.graalvm.shadowed.org.antlr.v4.runtime.atn.SemanticContext.Empty

Enclosing class:

SemanticContext

public static class SemanticContext.Empty
extends SemanticContext

Nested Class Summary

Nested classes/interfaces inherited from class org.graalvm.shadowed.org.antlr.v4.runtime.atn.SemanticContext

SemanticContext.AND, SemanticContext.Empty, SemanticContext.Operator, SemanticContext.OR, SemanticContext.PrecedencePredicate, SemanticContext.Predicate

Field Summary

Fields

Modifier and Type	Field and Description
static SemanticContext.Empty	Instance The default SemanticContext, which is semantically equivalent to a predicate of the form {true}?.

Constructor Summary

Constructors

Constructor and Description
Empty()

Method Summary

Modifier and Type	Method and Description
boolean	eval(Recognizer<?,?> parser, RuleContext parserCallStack) For context independent predicates, we evaluate them without a local context (i.e., null context).

Methods inherited from class org.graalvm.shadowed.org.antlr.v4.runtime.atn.SemanticContext

and, evalPrecedence, or

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

Instance

public static final SemanticContext.Empty Instance

The default SemanticContext, which is semantically equivalent to a predicate of the form {true}?.

Constructor Detail

Empty

public Empty()

Method Detail

eval

public boolean eval(Recognizer<?,?> parser,
                    RuleContext parserCallStack)

Description copied from class: SemanticContext

For context independent predicates, we evaluate them without a local context (i.e., null context). That way, we can evaluate them without having to create proper rule-specific context during prediction (as opposed to the parser, which creates them naturally). In a practical sense, this avoids a cast exception from RuleContext to myruleContext.

For context dependent predicates, we must pass in a local context so that references such as $arg evaluate properly as _localctx.arg. We only capture context dependent predicates in the context in which we begin prediction, so we passed in the outer context here in case of context dependent predicate evaluation.

Specified by:

eval in class SemanticContext