[clean-list] Clean unimplement code

[todoroki]

Hello, I'm uzm. I live in Tokyo Japan.
I'm a big fan of the Concurrent Clean language and enjoy it.

The other day, I found the unimplement code and I fixed it.
I hesitate whether to make the uniformity of the behavior of
Right and Center and Left or to make convenience.
I put the code here and please use it if you like it.
Thank you.

// windowvalidate.icl
 >getItemPosPosition _ _ _ _ windows tb
 >  = (zero,windows,tb)

<getItemPosPosition _ _ size itemPos windows tb
<    # (rect,tb)                = osScreenrect tb
<      screenDomain                = rectToRectangle rect
<      screenOrigin                = {x=rect.rleft,y=rect.rtop}
<      (exactW,exactH)            = toTuple size
<      {vx,vy}                = case itemPosOffset (snd itemPos) 
[(screenDomain,screenOrigin)] of
<                              Alt1Of2 v    = v
<                              _            = windowvalidateFatalError 
"getItemPosPosition _ _ (pos,center|right|left )" "pos in 
{Left,Right,Center}, but offset is illegal: OffsetAlign"
<         pos                       = case (fst itemPos) of
<                                       Center -> {x = (rect.rright - 
exactW)>>1 + vx, y = (rect.rbottom - exactH)>>1 + vy}
<                                       Right  -> {x = rect.rright - 
exactW + vx, y = vy}
<                                       Left   -> {x = vx, y = vy}
<                                       _      -> zero
<    = (pos,windows,tb)

uzm