org.antlr.v4.runtime.atn

Class SemanticContext.OR

java.lang.Object

org.antlr.v4.runtime.atn.SemanticContext

org.antlr.v4.runtime.atn.SemanticContext.OR

Enclosing class:

SemanticContext

public static class SemanticContext.OR
extends SemanticContext

A semantic context which is true whenever at least one of the contained contexts is true.

Nested Class Summary

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

SemanticContext.AND, SemanticContext.OR, SemanticContext.PrecedencePredicate, SemanticContext.Predicate

Field Summary

Fields

Modifier and Type	Field and Description
SemanticContext[]	opnds

Fields inherited from class org.antlr.v4.runtime.atn.SemanticContext

NONE

Constructor Summary

Constructors

Constructor and Description
SemanticContext.OR(SemanticContext a, SemanticContext b)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
boolean	eval(Recognizer<?,?> parser, RuleContext outerContext) For context independent predicates, we evaluate them without a local context (i.e., null context).
SemanticContext	evalPrecedence(Recognizer<?,?> parser, RuleContext outerContext) Evaluate the precedence predicates for the context and reduce the result.
int	hashCode()
String	toString()

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

and, or

Methods inherited from class java.lang.Object

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

Field Detail

opnds

@NotNull
public final SemanticContext[] opnds

Constructor Detail

SemanticContext.OR

public SemanticContext.OR(@NotNull
                  SemanticContext a,
                  @NotNull
                  SemanticContext b)

Method Detail

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

eval

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

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.

The evaluation of predicates by this context is short-circuiting, but unordered.

Specified by:

eval in class SemanticContext

evalPrecedence

public SemanticContext evalPrecedence(Recognizer<?,?> parser,
                             RuleContext outerContext)

Description copied from class: SemanticContext

Evaluate the precedence predicates for the context and reduce the result.

Overrides:

evalPrecedence in class SemanticContext

Parameters:

parser - The parser instance.

outerContext - The current parser context object.

Returns:

The simplified semantic context after precedence predicates are evaluated, which will be one of the following values.

• SemanticContext.NONE: if the predicate simplifies to true after precedence predicates are evaluated.
• null: if the predicate simplifies to false after precedence predicates are evaluated.
• this: if the semantic context is not changed as a result of precedence predicate evaluation.
• A non-null SemanticContext: the new simplified semantic context after precedence predicates are evaluated.

toString

public String toString()

Overrides:

toString in class Object