@Override
    public boolean equals(Object other) {
        if (this == other) return true;
        if ( ! (other instanceof Value)) return false;
        if ( ! ((Value) other).hasDouble()) return false;
        return this.asDouble() == ((Value) other).asDouble();
    }
Returns this or a mutable copy assigned the given value
searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/DoubleValue.java