cl-discount, basic CL interface to libmarkdown/discount

cl-discount.lisp

(ql:quickload :cffi)

  ;;; Nothing special about the "CFFI-USER" package.  We're just
  ;;; using it as a substitute for your own CL package.
(defpackage :cl-discount
  (:use :common-lisp :cffi)
  (:nicknames :discount)
  (:export #:markdown
           #:markdown-to-file))

(in-package :cl-discount)

(define-foreign-library discount
    (:unix (:or "libmarkdown.so.2.1.3" "libmarkdown.so.2" "libmarkdown.so"))
  (t (:default "libmarkdown")))

(use-foreign-library discount)

(defun markdown-to-file (string pathname)
  (let ((fptr (foreign-funcall "fopen"
                               :string (namestring pathname)
                               :string "w+"
                               :pointer))
        (doc (foreign-funcall "mkd_string"
                              :string string
                              :int (length string)
                              :int 0
                              :pointer)))
    (foreign-funcall "markdown"
                     :pointer doc
                     :pointer fptr
                     :int 0
                     :int)
    (foreign-funcall "fclose"
                     :pointer fptr
                     :int)
    (foreign-funcall "mkd_cleanup" :pointer doc :void)))

(defun markdown (string)
  (with-foreign-object (text-ptr :pointer)
    (let* ((doc (foreign-funcall "mkd_string"
                                 :string string
                                 :int (length string)
                                 :int 0
                                 :pointer))
           (compiled? (foreign-funcall "mkd_compile"
                                       :pointer doc
                                       :int 0
                                       :pointer))
           (len (foreign-funcall "mkd_document"
                                 :pointer doc
                                 :pointer text-ptr
                                 :int)))
      (declare (ignore compiled?))
      (prog1 (foreign-string-to-lisp (mem-ref text-ptr :pointer)
                                     :count len)
        (foreign-funcall "mkd_cleanup" :pointer doc :void)))))