Does hy have cons, car and cdr equivalents?

[yatsukha]

I really miss having cons, car and cdr, but I'm fairly new so are there any equivalents?

[brandonwillard]

They were removed from Hy a while back, but I created a package that mostly reproduces their semantics: https://github.com/pythological/python-cons.

[Kodiologist]

To create a list, use [ … ]. To get the first item (a la car), use (get x 0), or (first x) from the toolz library. To get all but the first item (a la cdr), use (slice x 1 None) (cut x 1 None), or (rest x) from Hyrule, or (drop 1 x) from toolz.

[Zambito1]

I am not super familiar with how slices work, but cut seems to behave closer to how I would expect for cdr to work.

=> (slice [1 2 3 4] 1 None)
(slice [1, 2, 3, 4] 1)
=> (slice '(a b c d) 1 None)
(slice hy.models.Expression([
  hy.models.Symbol('a'),
  hy.models.Symbol('b'),
  hy.models.Symbol('c'),
  hy.models.Symbol('d')]) 1)
=> (cut [1 2 3 4] 1 None)
[2 3 4]
=> (cut '(a b c d) 1 None)
'(b c d)

Is there a reason to prefer slice over cut?

[Kodiologist]

I really meant cut, yeah. (cut x …) is shorthand for (get x (slice …)) and more often useful than slice itself, since it's rare to use a slice object for anything other than an immediate index operation.

[brandonwillard]

Just so everyone is aware, those functions are not equivalents to cons, car, and cdr; they're just list creation, first/head, and rest/tail functions. They lack some important properties that would allow them to serve as replacements to cons, car, and cdr in most Lisp-like code.