(Re) LOGO-L> A better penreverse?

[fajoy@uio.satnet.net]

What about this. Sorry, a global variable is used.

Also a property list.

; First, lets define the inverse moves (ways)
Pprop "inverse "lt "rt
Pprop "inverse "rt "lt
Pprop "inverse "bk "fd
Pprop "inverse "fd "bk

; This should be run first
to ini
make "retrace []
end

; Moves' controller. It does the atomic move specified in the :waylist
; and keeps a list of inverse ways
to move :waylist
run :waylist
push "retrace (list gprop "inverse first :waylist last :waylist)
show :retrace 
end

; It runs the :retrace list using the specified :color
to unmove :color
localmake "pc pencolor
localmake "rt :retrace 
make "retrace []
setpc :color
foreach :rt [move ?]
setpc :pc
end

---------------------
Let's try this

cs ini move [fd 10]
[[bk 10]] ; this is output of the "show :retrace" in "move"

move [fd 10]
[[bk 10] [bk 10]]

move [rt 45]
[[lt 45] [bk 10] [bk 10]]

move [fd 10]
[[bk 10] [lt 45] [bk 10] [bk 10]]

move [rt 45]
[[lt 45] [bk 10] [lt 45] [bk 10] [bk 10]]

move [fd 10]
[[bk 10] [lt 45] [bk 10] [lt 45] [bk 10] [bk 10]]

unmove 5 ; in color 5
[[fd 10]]
[[rt 45] [fd 10]]
[[fd 10] [rt 45] [fd 10]]
[[rt 45] [fd 10] [rt 45] [fd 10]]
[[fd 10] [rt 45] [fd 10] [rt 45] [fd 10]]
[[fd 10] [fd 10] [rt 45] [fd 10] [rt 45] [fd 10]] 

; the inverse of [[bk 10] [lt 45] [bk 10] [lt 45] [bk 10] [bk 10]]

unmove 3 ; in color 3
[[bk 10]]
[[bk 10] [bk 10]]
[[lt 45] [bk 10] [bk 10]]
[[bk 10] [lt 45] [bk 10] [bk 10]]
[[lt 45] [bk 10] [lt 45] [bk 10] [bk 10]]
[[bk 10] [lt 45] [bk 10] [lt 45] [bk 10] [bk 10]]

; the inverse of the inverse



Daniel
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