Answer(There is actually no final answer, many places in the code can be improved.)
(defun natos-englishs ()
(list '(Alfa Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliet Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey Xray Zulu)
'(A B C D E F G H I J K L M N O P Q R S T U V W X Z)))
(defun convert-nato-english (item)
(destructuring-bind (natos englishs)
(natos-englishs)
(cond ((member item natos)
(nth (position item natos)
englishs))
((member item englishs)
(nth (position item englishs)
natos))
(t
(error "Unvalid")))))
(defun -mapcar (function list)
(if (null list)
nil
(cons (funcall function
(car list))
(-mapcar function
(cdr list)))))
(defun format-lists (function lists)
(format nil "~{~{~A~}~^ ~}"
(-mapcar (lambda (list)
(-mapcar function
list))
lists)))
(defun conve (english-lists)
(format-lists (lambda (english)
(string-capitalize
(write-to-string
(convert-nato-english english))))
english-lists))
(defun convn (nato-lists)
(format-lists (lambda (nato)
(write-to-string (convert-nato-english nato)
:case :downcase))
nato-lists))
(list (conve '((P R O)
(L A N)))
(convn '((Papa Romeo Oscar)
(Lima Alfa November))))
("PapaRomeoOscar LimaAlfaNovember" "pro lan")
