Extra argument for list accessors

[Jeremy Dunn]

I was thinking that it might be nice to add an extra optional argument at the end of the functions FIRST, LAST, NTH, REST and SLICE that represent a value that is to be substituted at that position. So for example

(first "cat") -> "c"
(first "cat" "b") -> "bat"

or

(nth 2 '(2 3 7 77 8) 6) -> '(2 3 6 77 8)

and so on.

[Lutz]

thats what 'set-nth' is for:

Code: Select all

(set-nth 2 '(2 3 7 77 8) 6) => (2 3 6 77 8) 

Lutz