ManipulateContextHelper
Helper class used for context commands
plan for context manipulation:
action = {replace out with in|prepend in to out|append in to out}
valuein
indexin|keyin|null
foreach = {value in list|key in map|value in map|int|null}
change = {expand to singleton list|collapse list to set|expand set to map keys|convert map keys to set|convert set to list|convert map values to list}
valueout
indexout|keyout|null
foreach = {value in list|key in map|value in map|int|null}
change = {collapse list to set|expand set to map keys|convert map keys to set|convert set to list|convert map values to list |