I submitted CLAZY and CL-ENUMERATIONS to Quicklisp and found out that there were some problems with them. Mostly due to (unwarranted) package locks in SBCL and CLISP. Fixing these problems led to some revisitation of the code base and subsequent improvements (I hope).

Both libraries should appear in future Quicklisp releases.



HTML in Common Lisp: code or fill?

I finally got around to write my very own HTML documentation system. Of course, this may be pointless and useless, but I found the alternatives "out there" lacking this or that (obviously!). So here I am, trying to automate the process of producing documentation like that of CLAZY, which I hand-crafted in the past. In the process, needless to say, I got carried away and got lost in the land of featurism only to contemplate my overall ignorance of most things webbish.

As usual, Edi Weitz came to my rescue by offering his CL-WHO and HTML-TEMPLATE, which raised a question: which of the two approaches is best? Note that the answer should consider how many dependencies my system files can have.

Let's start with the simple problem I have: I need to produce a .html file that contains, say, a "header" for my documentation. I could do it using CL-WHO in the following way (just a snippet, not working...)

(defun produce-header-file (fs header-pathname)
(declare (type frameset fs)
      (type pathname header-pathname))
(let ((fs-order (frameset-order fs))
   (fs-head-title (frameset-head-title fs))
   (fs-body-title (frameset-body-title fs))
(with-open-file (hs header-pathname
                   :direction :output
                   :if-exists :supersede
                   :if-does-not-exist :create)
 (with-html-output (hs hs :indent t)
   (fmt "~A" (cl-fad:pathname-as-file header-pathname))
   (fmt +doctype-frameset-control-string+)
     (:title (str fs-head-title))
     (:link :rel "stylesheet" :href "clstyle.css"))
    (:body :style "margin: 0pt 0pt 0pt 0pt;"
      :class "header"
      :style "padding-left: 2em; padding-top: 5pt; color: #41286f; font-size: 14pt"
      (:strong (str fs-body-title))
       :class "navigation"
       :style "right: 2m"
        :href "index.html"
        :class "navigation-link-selected"
        :target "_parent"
        (str "Home"))

Or I could use HTML-TEMPLATE and ship around a "template" file like the following (again, this is just a snippet and contains errors):

<!-- header.html -->

"-//W3C//DTD XHTML 1.0 Strict//EN"

<title><!-- TMPL_VAR HEAD_TITLE --></title>
<link rel="stylesheet" href="clstyle.css">

<body style="margin: 0pt 0pt 0pt 0pt;">

<div class="header"
style="padding-left: 2em; padding-top: 5pt;  ">
<strong><i><!-- TMPL_VAR BODY_TITLE --></i></strong><br/>

<div class="navigation" style="right: 2m">
<!-- TMPL_LOOP frames -->
<!-- TMPL_IF current_frame -->
<a href=<!-- TMPL_VAR frame --> class="navigation-link-selected" target=_parent><!-- TMPL_VAR f_nav_name ->></a>
<!-- TMPL_ELSE -->
<a href=<!-- TMPL_VAR frame --> class="navigation-link" target=_parent><!-- TMPL_VAR f_nav_name ->></a>
<!-- /TMPL_IF -->
<!-- /TMPL_LOOP -->



<!-- end of file : header.html -->

I am inclined to go the CL-WHO way. I do not have to ship around an extra file and record its location etc etc; yet the HTML-TEMPLATE does have appeal. Any ideas out there?



NEW post


here is a NEW post after a long time. And the topic of this post is NEW. Of course, this is old stuff, but here it is: it's a post about the new operator. I'd bet there are many other little hacks like this floating around, but I finally got sucked in into writing a little library that introduces a new operator (and a newq one) in Common Lisp.

Why? After a very long time of putting up with make-instance and make-this and make-that, and after many other brain things going on in my head (cit. King Julien of the Lemurs) I decided that Common Lisp needed something capable of doing the following:

cl-prompt> (defclass foo () ())
cl-prompt> (new 'foo)
#<FOO instance 42>

or even

cl-prompt> (newq foo)
#<FOO instance 42>

So; what's the big deal? Not much, but I also want to be able to write:

cl-prompt> (newq (array single-float (2 2)) '((1.0 0.0) (0.0 1.0)))
#2A((1.0 0.0) (0.0 1.0))

The problem is that as soon as you wade in CL "type specifiers" land, you hit the dreaded "implementation dependent" wall, or, worse, the "this is not even mentioned in the ANSI spec" wall. Think of DEFSTRUCT and the fact that there is no portable way to get to the constructor, not to mention DEFTYPE.

Apart from that, I think that the little piece of code I wrote would maybe make programming in CL feel more in tune with the times. After all you can also write things like the following, which I think are rather cool.

cl-prompt> (new '(mod 42) (read))
Error: 1024 is not of type (INTEGER 0 (42)).

What do you think? Is this worth a CDR? Ping me if you want to see the code.