(This is a repost of an old blog post of mine from Teknik.)

#alexandria #common-lisp

I had a hash table in a running Common Lisp image that I wanted to print readably while preserving object identity (mostly to avoid data duplication).

Alexandria and Bike from #lisp came to the rescue.

;;; (ql:quickload :alexandria)

(defun print-hash-table-readably (hash-table
                                  &optional (stream *standard-output*))
  "Prints a hash table readably using ALEXANDRIA:ALIST-HASH-TABLE."
  (let ((test (hash-table-test hash-table))
        (*print-circle* t)
        (*print-readably* t))
    (format stream "#.(ALEXANDRIA:ALIST-HASH-TABLE '(~%")
    (maphash (lambda (k v) (format stream "   (~S . ~S)~%" k v)) hash-table)
    (format stream "   ) :TEST '~A)" test)
    hash-table))