A good attitude, that's what counts. --- Good attitude is an appositive?

A good attitude, that's what counts.

At first I saw this and thought comma splice; but that can't be because a splice requires two clauses.

In this sentence "a good attitude" is in apposition to the pronoun "that;" that's why this sentence is grammatically correct? (if I'd divided these two clauses by a comma then I'd be splicing with a comma.)

Solution 1:

As John Lawler states in the comments:

This is called "Left-Dislocation", and moves the subject to the beginning of the sentence, in a constituent of its own, followed by the rest of the sentence, but with a coreferential pronoun subject. "Right-Dislocation" works in the other direction, often with different intonation, and thus punctuation: That's what counts -- a good attitude. Both are transformations of What counts is a good attitude. Which is itself a pseudo-cleft transformation of A good attitude counts. See how sentences swell up?

Here's a list of the top 200-plus English transformations, with examples.