public static <T> ToDouble<T> longToDouble(ToLong<T> expression) {
        return expression.asDouble();
    }
Creates and returns an expression that converts the result of the
specified expression into a {@code double} by casting.

@param expression  the initial expression
@param <T>         the input type
@return            the new expression
runtime-parent/runtime-compute/src/main/java/com/speedment/runtime/compute/expression/Expressions.java