First lisp steps. elisp examples. http://ergoemacs.org/emacs/elisp_basics.html

local_variables.lisp

(;; my block
 (let (
       (str "string!")
       (local_list (list 1 2 3)))
 (message "This is a string %s" str) ;; prints to *Message* buffer 
 (message "This is a list %S" local_list)
 nil
) ;; => returns nil

;; from emacs 24 eslip simulates lexical scoping though it has
;; dynamic scoping
;; that is a difference to common lisp, which has lexical scoping by default
;; avoid macro usage it brings in dynamic scoping

parseDate.lisp

(defun parseDate (dateStr)
  "Parses the date from YYYY.mm.DD
  (parseDate "2016.03.12") -> (2015 3 12)"
  ;(interactive)
  (string-match "^\\([0-9]+\\)\.\\([0-9]+\\)\.\\([0-9]+\\).*" dateStr)
  (mapcar 'string-to-number (list
			   (match-string 1 dateStr)
			   (match-string 2 dateStr)
			   (match-string 3 dateStr))))

(provide 'parseDate)

read-lines.lisp

(defun read-lines (filePath)
  "Return a list of lines of a file at filePath."
  (with-temp-buffer
    (insert-file-contents filePath)
    (split-string (buffer-string) "\n" t)))
(provide 'read-lines)