The while concept is an extension of the English word "while" based on a former bug in the Taminations sequencer.
Callers already use the word "while" all the time, in contexts like "centers swing thru while the ends trade". The while concept defines these cases in the intuitive way: the people designated by the first designator do the first call, and the people designated by the second designator do the second call. But what if some people are designated by both designators?
The full definition of the while concept is as follows: on "X while Y", first memorize the path you would walk in if you were to do Y. Then, do X. Then, walk in the path you memorized.
To explain the motivation behind this definition, I have to tell a short story.
When I was a wee little dancer, learning plus for the first time, I spent a lot of time studying calls on Taminations. (The Tech Squares plus class meets "only" once a week, and I was so excited by the concept of square dancing that this was not nearly enough to satiate my desires. I ended up teaching myself plus by about week 3.)
As part of this, I would sometimes type random calls into the sequencer, just to see what would happen. I'm not sure what prompted me to do this, but one such call was plusacey deucey, which I typed in from a squared set. I don't remember the reason; my working hypothesis is that it was the alphabetically first plus call, so I saw it in the list and just input it having no idea what it meant.
As any plus dancer would know, plusacey deucey from a squared set is complete nonsense, and should have resulted in the sequencer yelling at me. That is not what happened, and what actually happened was... rather more surprising, shall we say.
Yes, from a squared set, Taminations's conception of plusacey deucey is "heads trade, heads run away". (This is obviously a bug, which has since been fixed.)
As baffling as this behavior is, like many confusing things computers do, it has a logical explanation. It's actually a confluence of several facts:
- Taminations defines plusacey deucey as the result of evaluating the literal string
Center 4 Trade While Outer 4 Circulate.
- From a squared set, the code happens to identify the heads as being both the "Center 4" and the "Outer 4".
- When the same dancers appear on both sides of "While", the code evaluates both calls in sequence, but as if they started from the same starting position.
As a result, the call "Acey Deucey" makes Taminations believe that the heads should do a Trade while the heads do a Circulate. The action for Trade is what you'd expect, and it's what they do. The action for Circulate, from a squared set, is to walk forward 3 positions (passing right shoulders), circulating within their box of 4.
So the heads perform the Trade action, which is to flip inwards, and then perform the Circulate action, which is to walk forward 3 positions.
After discovering all this by digging through the source code, I realized that I could, uh... have some fun with this.