Package org.antlr.v4.runtime.atn
Class SemanticContext.Empty
java.lang.Object
org.antlr.v4.runtime.atn.SemanticContext
org.antlr.v4.runtime.atn.SemanticContext.Empty
- Enclosing class:
SemanticContext
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Nested Class Summary
Nested classes/interfaces inherited from class org.antlr.v4.runtime.atn.SemanticContext
SemanticContext.AND, SemanticContext.Empty, SemanticContext.Operator, SemanticContext.OR, SemanticContext.PrecedencePredicate, SemanticContext.Predicate
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final SemanticContext.Empty
The defaultSemanticContext
, which is semantically equivalent to a predicate of the form{true}?
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
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.antlr.v4.runtime.atn.SemanticContext
and, evalPrecedence, or
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Field Details
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Instance
The defaultSemanticContext
, which is semantically equivalent to a predicate of the form{true}?
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Constructor Details
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Empty
public Empty()
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Method Details
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eval
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 classSemanticContext
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