New functions take, drop, {take,drop}-{while,until}.

* lib.c (take_list_fun, take_while_list_fun,
take_until_list_fun): New static functions.
(take, take_while, take_until, drop, drop_while,
drop_until): New functions.

* eval.c (eval_init): Register intrinsics take,
take-while, take-until, drop, drop-while, drop-until.

* txr.1: Documented.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib.h b/lib.h
index 41b8608b..e48904a4 100644
--- a/lib.h
+++ b/lib.h
@@ -872,6 +872,12 @@ val pos(val list, val key, val testfun, val keyfun);
 val pos_if(val pred, val list, val key);
 val pos_max(val seq, val testfun, val keyfun);
 val pos_min(val seq, val testfun, val keyfun);
+val take(val count, val seq);
+val take_while(val pred, val seq, val keyfun);
+val take_until(val pred, val seq, val keyfun);
+val drop(val count, val seq);
+val drop_while(val pred, val seq, val keyfun);
+val drop_until(val pred, val seq, val keyfun);
 val in(val seq, val key, val testfun, val keyfun);
 val set_diff(val list1, val list2, val testfun, val keyfun);
 val copy(val seq);