Comments on: Arc-macros, baby. Arc-macros. (part II)

By: Kon Lovett

Kon Lovett — Sat, 16 Feb 2008 02:55:50 +0000

If your domain is not boolean than take a look at “filter-map”.

Chicken uses the “cut” macro for ‘{foo _ 2 _}’ – ‘(cut foo <> 2 <>)’. Not as concise but save thes ‘{}’ brackets for something really important.

By: Hans Nowak

Hans Nowak — Thu, 31 Jan 2008 23:35:06 +0000

Well, I was talking about replacing all instances of X with Y, either shallow or nested. Note that I am not asking you to write the function for me! :-) I was just wondering why such a beast does not exist. Maybe it’s not common enough an operation? Or is this another one-liner? :)

By: John Cowan

John Cowan — Thu, 31 Jan 2008 22:59:26 +0000

Because it’s a one-liner:

(define (set-elt! lst n obj) (set-car! (drop lst n) obj)