so's

So that, in order that.

Of all the queer collections of humans outside of a crazy asylum, it seemed to me this sanitarium was the cup winner. […] When you're well enough off so's you don't have to fret about anything but your heft or your diseases you begin to get queer, I suppose.

To the extent that.

"Has he been working?" / "Not so's you'd notice."

So is.

My father's at work right now. So's my mother.

So has.

My father's gone away on holiday. So's my mother.