Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).

Raise an exception if the needle is missing.

If there is more than one occurrence then return the smallest index to the needle.

Extra credit
Return the largest index to a needle that has multiple occurrences in the haystack.

See also
 Search a list of records

(de lastIndex (Item Lst)
   (- (length Lst) (index Item (reverse Lst)) -1) )
 
(de findNeedle (Fun Sym Lst)
   (prinl Sym " " (or (Fun Sym Lst) "not found")) )
 
(let Lst '(Zig Zag Wally Ronald Bush Krusty Charlie Bush Bozo)
   (findNeedle index 'Washington Lst)
   (findNeedle index 'Bush Lst)
   (findNeedle lastIndex 'Bush Lst) )