Add list_head_opt and list_tail_opt
Add two new function:
- List.head_opt
- List.tail_opt
which returns none if the list is empty and respectively hd and tl if the list is CONS (hd,tl)
fix #1058 (closed)
Edited by Pierre-Emmanuel Wulfman
Add two new function:
which returns none if the list is empty and respectively hd and tl if the list is CONS (hd,tl)
fix #1058 (closed)