Live coding session at Lisp Meet Up #9. Case insensitive word count.

meetup9.lisp

(defparameter *test-data*
  "PAPPLY is a macro family that offers a shorthand form to write the partial
   application of fucntions.

   PAPPLY macro generates a function object by partial applying the fucntion
   specified as the first argument to the rest arguments. A special symbol `_`
   is utilized as a place holder that denotes not-yet-fixed arguments.

   (papply (list (1+ _) (string _)))
   ;=> #'(LAMBDA (#:P0 #:P1 &REST #:REST0)
   (APPLY #'LIST (1+ #:P0) (STRING #:P1) #:REST0))

APAPPLY macro introduces anaphoras and made possible to utilize one parameter
multiple times. A symbol `An` (n is a number) appears in APAPPLY form is
recognized as the nth parameter of generated function object.")

(ql:quickload :cl-ppcre)

(use-package :cl-ppcre)

(show-hash-table
  (let ((table (make-hash-table :test #'equalp)))
    (dolist (word (split "\\s+" *test-data*) table)
      (incf (gethash word table 0)))))

utils.lisp

(defun show-hash-table (ht &optional (stream t))
  (format stream "~% key -> value ~%")
  (format stream "--------------~%")
  (maphash
    (lambda (k v)
        (format stream "~a -> ~a~%" k v))
    ht))