private int consumeNumericArgument() {
        if (!tokens.currentIs(LBRACE)) return 0;
        tokens.skip(LBRACE);
        if (!tokens.currentIsNoIgnore(NUMBER)) throw new IllegalArgumentException("Expected an integer argument");
        int distance = Integer.valueOf(tokens.next().image);
        if (!tokens.skip(Token.Kind.RBRACE)) throw new IllegalArgumentException("Expected a right brace following the argument");
        return distance;
    }
Returns the argument to this operator or 0 if none
container-search/src/main/java/com/yahoo/prelude/query/parser/AdvancedParser.java