support for POINT class

[kevinhikaruevans]

Since node-mysql supports SELECTing and casting the POINT class, it would make sense to also support escaping POINTs during INSERTs and UPDATEs. Currently, if you SELECT a field with a point, it'll return a plain object with x and y attributes. This PR will allow it to also INSERT and UPDATE an object with x and y attributes.

I have no idea if this was the correct way to append a new type in SqlString, but it works fine for me. Date casts were defined there, so it seemed like a good place to start. The POINT function is defined here.

[dougwilson]

It needs tests, if you are so inclined :)

[kevinhikaruevans]

Added a test for it! Not sure how many tests are required. There probably should be a separate function for geometry in SqlString, like SqlString.geometryToFunction() or something.

[dougwilson]

That's fine, I just wanted a test so I know what you were expecting to happen. So I see form the test, it has the issue I described, where before your change that objects would have resulted in x = 0, y = 1, but now it results in POINT(0,1) which is totally breaking. I thought you said you would make it only apply to objects within other objects passed to escape?

For example, this use-case needs to continue to work with your change:

connection.query('INSERT INTO data SET ?', {x: 3, y: 7})

where there is an x column and a y column on the data table.

[kevinhikaruevans]

Oh, I intended it for it to be objects within objects. I didn't know escape would be called on all objects being passed, I just thought it was called on objects being passed into single fields.

[dougwilson]

OK, as long as that is your intention. I can adjust your PR then later :)

[dougwilson]

We can also make this a little less risky by saying "if it has x and y and no other properties"