Should we have a relative version of zip?

[yotamDvir]

This is zip as it is now:

elm-pivot/Pivot/Map.elm

Lines 81 to 96 in cee1b98

	zip : Pivot a -> Pivot ( Int, a )
	zip pvt =
	let
	n =
	lengthL pvt
	onC =
	(,) n
	onL =
	List.indexedMap (,)
	onR =
	List.indexedMap ((+) (n + 1) >> (,))
	in
	mapCLR_ onC onL onR pvt

It indexes the pivot like a list, without any regard to where the center is.
It may be beneficial to have a relative version.

 zipRelative : Pivot a -> Pivot ( Int, a ) 
 zipRelative pvt = 
     let 
         onC = 
             \x -> (0,x) 
  
         onL = 
             List.indexedMap (\i x -> (-1 - i,x)) 
  
         onR = 
             List.indexedMap (\i x -> (i + 1, x)) 
     in 
mapCLR_ onC onL onR pvt 

For example, a situation where one knows their pivot is going to get jumbled, and would like to retain their current positions afterwards.

In such a case we could also change the name of zip to zipAbsolute, leaving less room for confusion. To increase uniformity, we could further replace goTo by goAbsolute; and goBy by goRelative.

In fact, why is it called zip in the first place? index is better...