Double substitution fix

What is a double-substitution in volleyball?

When the setter and opposite in the court are substituted with the second opposite and the second setter respectively, the substitution is called double substitution.

Two approaches for double substitutions

In general, the substitution follows this pattern:

- Setter 1 (out) for Opposite 2 (in)

- Opposite 1 (out) for Setter 2 (in)

In DataVolley files, there are two approaches to perform a double-substitution:

1. Maintain the previous setter rotation, i.e., the rotation is the previous court position of Setter 1

2. Swap the setter rotation, i.e., the new Setter 2 court position becomes the current rotation

For several reasons, I prefer solution 2 (swapping the setter position). For example, if the setter rotation was 1, after a double substitution the setter rotation should become 4, and so on.

This app performs rotation swap (codes *z and az), new setter assignments (codes *P and aP), and setter sets correction (setter codes E).