protected void accept(CharStream input, LexerActionExecutor lexerActionExecutor,
						  int startIndex, int index, int line, int charPos)
	{
		if ( debug ) {
			System.out.format(Locale.getDefault(), "ACTION %s\n", lexerActionExecutor);
		}

		// seek to after last char in token
		input.seek(index);
		this.line = line;
		this.charPositionInLine = charPos;

		if (lexerActionExecutor != null && recog != null) {
			lexerActionExecutor.execute(recog, input, startIndex);
		}
	}
Given a starting configuration set, figure out all ATN configurations
 we can reach upon input {@code t}. Parameter {@code reach} is a return
 parameter.
runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java