lix/tests/lang/eval-okay-flatten.nix
Eelco Dolstra d315210612 * Added a builtin function `isList' to test whether a value is a list.
With this primitive, a list-flattening function can be implemented
  (NIX-55, example is in tests/lang/eval-okay-flatten.nix).
2006-09-22 14:55:19 +00:00

20 lines
349 B
Nix

let {
fold = op: nul: list:
if list == []
then nul
else op (builtins.head list) (fold op nul (builtins.tail list));
concat =
fold (x: y: x + y) "";
flatten = x:
if builtins.isList x
then fold (x: y: (flatten x) ++ y) [] x
else [x];
l = ["1" "2" ["3" ["4"] ["5" "6"]] "7"];
body = concat (flatten l);
}