💡📝H. G. Muller wrote on Thu, May 20, 2021 07:12 AM UTC:
Modifier repetition
The diagram now implements repetition of modifier groups through including those in parentheses: x(y)zA = xzAxyzAxyyzA.... This makes it possible to encode moves like a Mao-rider or Quintessence (= Crooked Nightrider). I was a bit dismayed, though, by how lengthy these encodings still are. The Quintessence, for example, would require (alar)N(aral)Nar(alar)Nal(aral)N. The problem is two-fold: because the move deflects alternately left or right, the smallest repeating group needs to contain two legs. But we need to indicate both moves with an even and an odd number of steps.
And to indicate that the two turns in the repeating group have to be made in opposit direction, we need to explicitly write l and r. Which means we have to write everything a second time for indicating the mirror image. That problem already existed for pieces like the Falcon, where the zig-zag path is either aflafrK or afraflK.
The z and q modifiers
So far XBetza used z and q only in their legacy meaning of crooked and circular pieces, respectively. There can be a very natural use of these in multi-leg move descriptions too, though. In particular in continuation legs (which then would never interfere with the legacy use on single-leg moves).
So in multi-leg moves we use z and q as alternatives to l and r. Where q means 'the same as in the previous leg', while z means the opposit. If there was no l, r or s in any previous leg, both z and q mean the same as s.
This allows move specifications like (az)N for the Quintessence, which 'expands' to NazNazazNazazazN.... The first z in a longer path can be read either as l or r, (so the descriptions actually define two mirror-image paths) and from then on they alternate. The zig-zag path of the Falcon can then be written as afsafzK. The Rose could be writen as (afq)N.
Modifier repetition
The diagram now implements repetition of modifier groups through including those in parentheses: x(y)zA = xzAxyzAxyyzA.... This makes it possible to encode moves like a Mao-rider or Quintessence (= Crooked Nightrider). I was a bit dismayed, though, by how lengthy these encodings still are. The Quintessence, for example, would require (alar)N(aral)Nar(alar)Nal(aral)N. The problem is two-fold: because the move deflects alternately left or right, the smallest repeating group needs to contain two legs. But we need to indicate both moves with an even and an odd number of steps.
And to indicate that the two turns in the repeating group have to be made in opposit direction, we need to explicitly write l and r. Which means we have to write everything a second time for indicating the mirror image. That problem already existed for pieces like the Falcon, where the zig-zag path is either aflafrK or afraflK.
The z and q modifiers
So far XBetza used z and q only in their legacy meaning of crooked and circular pieces, respectively. There can be a very natural use of these in multi-leg move descriptions too, though. In particular in continuation legs (which then would never interfere with the legacy use on single-leg moves).
So in multi-leg moves we use z and q as alternatives to l and r. Where q means 'the same as in the previous leg', while z means the opposit. If there was no l, r or s in any previous leg, both z and q mean the same as s.
This allows move specifications like (az)N for the Quintessence, which 'expands' to NazNazazNazazazN.... The first z in a longer path can be read either as l or r, (so the descriptions actually define two mirror-image paths) and from then on they alternate. The zig-zag path of the Falcon can then be written as afsafzK. The Rose could be writen as (afq)N.