Changing the id of all absent pieces to '-' appears to have worked for on-page playing. (Flush the browser cache, as I also had to fix something in the Diagram script, to prevent the Start Position button would crash on a highlighted empty square, which can be a remnant of defining the morph board.) And it makes future editing only slightly more cumbersome, as you would have to redefine a new id. Perhaps I should reserve clearing the id to ids that have the same id as a participating piece; those would have to be redefined anyway if one wants those to appear together in the same variant.
Another matter is how to enable the user to enter a capture matrix. The problem here is that this, unlike the morph board, might not fit in the board, but would need a board that has all piece types as 'coordinates'. For games with multiple rows of pieces this is usually larger than the board. (Even for the 8x8 Team-Mate Chess it is!)
I suppose I could let the user enter the matrix per row, and then assign that row to a piece (the moving piece). Then there could be an Nx2 auxiliary board displayed, which on the upper rank shows all participating piece types, and pieces could be dragged to the lower rank to indicate what the moving piece should change to when it captures the piece displayed above it.
Changing the id of all absent pieces to '-' appears to have worked for on-page playing. (Flush the browser cache, as I also had to fix something in the Diagram script, to prevent the Start Position button would crash on a highlighted empty square, which can be a remnant of defining the morph board.) And it makes future editing only slightly more cumbersome, as you would have to redefine a new id. Perhaps I should reserve clearing the id to ids that have the same id as a participating piece; those would have to be redefined anyway if one wants those to appear together in the same variant.
Another matter is how to enable the user to enter a capture matrix. The problem here is that this, unlike the morph board, might not fit in the board, but would need a board that has all piece types as 'coordinates'. For games with multiple rows of pieces this is usually larger than the board. (Even for the 8x8 Team-Mate Chess it is!)
I suppose I could let the user enter the matrix per row, and then assign that row to a piece (the moving piece). Then there could be an Nx2 auxiliary board displayed, which on the upper rank shows all participating piece types, and pieces could be dragged to the lower rank to indicate what the moving piece should change to when it captures the piece displayed above it.