It seems like this tune creates a little chaos when folks play it together.
People have their own interpretation and understanding about the "A" part and B" part.
Here's my take on the matter.
For a standard AABB tune, each "A" or "B" part is 8 measures long or 16 beats.
Most of the time the "A" parts are nearly identical. In the case of Bonaparte Crossing the Rhine,
the first four measures of each "A" part are the same but not the last four measures.
Now the "B" part. Again each "B" part is 8 measures long or 16 beats.
The "B" parts are not identical in Bonaparte so they are written out separately.
The 2nd "B" part is like the "A" part in this tune, talk about confusing.
In conclusion, most "square" fiddle tunes are 32 measures long or 64 beats.
This matches the set of figures in a contra or square dance.
Each time through the dance takes 64 beats, after which the pattern is repeated.