Introducing cl-cmark

For the past few weeks I have been working on a little side project, a library of Common Lisp bindings to cmark, the CommonMark reference implementation: cl-cmark (GitHub mirror). CommonMark is a dialect of Markdown which aims to remove any ambiguity, clean up the language specification and provide a common dialect of Markdown for other projects to use. The cmark library is the reference implementation for parsing CommonMark. It is written in C, so creating bindings for other language is fairly simple.

The project is very much feature complete and tested, but I have yet to write the manual and declare the API stable. Users can use cl-cmark to parse CommonMark text into a tree of nodes and traverse that tree. Here is a small example from the readme:

(defpackage #:cmark-user
 (:use #:cl #:cmark))
(in-package #:cmark-user)

(defvar *document-tree* (cmark::parse-document "Hello *world*!")
 "Parse the document into a tree of nodes")

(defun print-node (node &optional (level 0))
 "Recursively print each node and its children at progressively deeper
 (format t "~&~A~A"
         (make-string (* 2 level) :initial-element #\Space)
         (class-name (class-of node)))
 (dolist (child (cmark::node-children node))
   (print-node child (1+ level))))

(print-node *DOCUMENT-TREE*)

This produces the following output:


There are actually two systems in the repository: libcmark and cmark. The libcmark system is mostly a low-level 1:1 binding to the C library; most users should never have to use it, but one could build a custom high-level lispy system on top of it. The cmark system is what most users should use, it an provides idiomatic lispy API that hides the gory details of C and is built on top of libcmark.

For now the project is not yet in Quicklisp, but it is very light on dependencies (only on CFFI and flexi-streams). Once I reach version 1.0 I will see to it that I add for formal request for inclusion in Quicklisp.