Dlist (and SList) splice operations

[monarch_dodra]

Are there any plans to implement splice operations on Dlists and 
Slists?

I remember reading in a post somewhere that the problem was 
mostly a "defining the interface" problem. Is this true?

Or where they purposefully not added to the library? Maybe to 
adhere to the standardized container interface?

Should I invest any effort on my end to try to get that into the 
library?