[CALCITE-3380] implement power method in Expressions.

[xy2953396112]

implement power method in Expressions.
before:
Extensions.todo();

[julianhyde]

I don't think we need this method. linq4j is tied to the java language. There is no power operator in java, therefore people should not be using the Expressions.power function, but instead make a method call.

Rather than Expressions.power(a, b) use Expressions.call(null, Math.class.getMethod("power"), a, b). Then I think the evaluate will be able to evaluate it without any extra work.

[xy2953396112]

I don't think we need this method. linq4j is tied to the java language. There is no power operator in java, therefore people should not be using the Expressions.power function, but instead make a method call.

Rather than Expressions.power(a, b) use Expressions.call(null, Math.class.getMethod("power"), a, b). Then I think the evaluate will be able to evaluate it without any extra work.

It is more convenient for users to use Expressions.power(a, b)。

[julianhyde]

I agree that it is a bit more convenient. But it goes against the philosophy of this class and package. We should not do it.

[danny0405]

Close because it is not needed.