antlr4ng
Version:
Alternative JavaScript/TypeScript runtime for ANTLR4
48 lines (47 loc) • 1.77 kB
TypeScript
import { TokenStream } from "../TokenStream.js";
import { ATNConfigSet } from "./ATNConfigSet.js";
/**
* This is the base class for gathering detailed information about prediction
* events which occur during parsing.
*
* Note that we could record the parser call stack at the time this event
* occurred but in the presence of left recursive rules, the stack is kind of
* meaningless. It's better to look at the individual configurations for their
* individual stacks. Of course that is a {@link PredictionContext} object
* not a parse tree node and so it does not have information about the extent
* (start...stop) of the various subtrees. Examining the stack tops of all
* configurations provide the return states for the rule invocations.
* From there you can get the enclosing rule.
*/
export interface DecisionEventInfo {
/**
* The invoked decision number which this event is related to.
*
* @see ATN#decisionToState
*/
decision: number;
/**
* The configuration set containing additional information relevant to the
* prediction state when the current event occurred, or `null` if no
* additional information is relevant or available.
*/
configs: ATNConfigSet | null;
/**
* The input token stream which is being parsed.
*/
input: TokenStream;
/**
* The token index in the input stream at which the current prediction was
* originally invoked.
*/
startIndex: number;
/**
* The token index in the input stream at which the current event occurred.
*/
stopIndex: number;
/**
* `true` if the current event occurred during LL prediction;
* otherwise, `false` if the input occurred during SLL prediction.
*/
fullCtx: boolean;
}