PredictionMode enum

This enumeration defines the prediction modes available in ANTLR 4 along with utility methods for analyzing configuration sets for conflicts and/or ambiguities.

Inheritance

Constructors

PredictionMode()
const

Values

SLL → const PredictionMode

The SLL(*) prediction mode. This prediction mode ignores the current parser context when making predictions. This is the fastest prediction mode, and provides correct results for many grammars. This prediction mode is more powerful than the prediction mode provided by ANTLR 3, but may result in syntax errors for grammar and input combinations which are not SLL.

When using this prediction mode, the parser will either return a correct parse tree (i.e. the same parse tree that would be returned with the {@link #LL} prediction mode), or it will report a syntax error. If a syntax error is encountered when using the {@link #SLL} prediction mode, it may be due to either an actual syntax error in the input or indicate that the particular combination of grammar and input requires the more powerful {@link #LL} prediction abilities to complete successfully.

This prediction mode does not provide any guarantees for prediction behavior for syntactically-incorrect inputs.

LL → const PredictionMode

The LL(*) prediction mode. This prediction mode allows the current parser context to be used for resolving SLL conflicts that occur during prediction. This is the fastest prediction mode that guarantees correct parse results for all combinations of grammars with syntactically correct inputs.

When using this prediction mode, the parser will make correct decisions for all syntactically-correct grammar and input combinations. However, in cases where the grammar is truly ambiguous this prediction mode might not report a precise answer for exactly which alternatives are ambiguous.

This prediction mode does not provide any guarantees for prediction behavior for syntactically-incorrect inputs.

LL_EXACT_AMBIG_DETECTION → const PredictionMode

The LL(*) prediction mode with exact ambiguity detection. In addition to the correctness guarantees provided by the {@link #LL} prediction mode, this prediction mode instructs the prediction algorithm to determine the complete and exact set of ambiguous alternatives for every ambiguous decision encountered while parsing.

This prediction mode may be used for diagnosing ambiguities during grammar development. Due to the performance overhead of calculating sets of ambiguous alternatives, this prediction mode should be avoided when the exact results are not necessary.

This prediction mode does not provide any guarantees for prediction behavior for syntactically-incorrect inputs.

Properties

hashCode → int
The hash code for this object.
no setterinherited
index → int
A numeric identifier for the enumerated value.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited

Constants

values → const List<PredictionMode>
A constant List of the values in this enum, in order of their declaration.