Use with-slots for initializers, readers only please!

docs/hacking.md

@@ -243,27 +243,6 @@ or other purposes. We should be able to build the paths at instance
 creation time and scrap the slugs altogether. Note that this will
 require changes to how we sort `NUMERIC-INDEX`.
 
-### Immutable Data
-
-Currently, most of our content classes (and the config class) have
-*accessor* slots in addition to *reader* slots. There should be no
-need for accessors as our data doesn't change after
-initialization. They are computed from the git repo, dumped into
-templates, and that's it. This is really a question of how we
-initialize things. I settled on the current `load-content` scheme,
-flawed as it is, because it is simple and lightweight.
-
-Content files in the git repo have a file extension denoting the
-content type, a header section with metadata and a text body. That
-gets transformed into a `construct` call (and ultimately
-`make-instance`) to the class matching the file extension, and a bunch
-of initargs. We avoid code duplication for lots of unique
-constructors, but we lose out some in error handling, separation of
-interface and implementation, etc.
-
-Keene's Object Oriented Programming in CL has good advice on this
-situation, specifically on page 162, Separation of Initargs and Slot Names.
-
 ### Finish up Basic Deploy
 
 The deploy method has been simplified and a git-hook plugin added.

plugins/static-pages.lisp

@@ -20,8 +20,9 @@
 
 (defmethod initialize-instance :after ((object page) &key)
   ;; Expect all static-pages to be written in Markdown for now.
-  (with-accessors ((text content-text)) object
-    (setf text (render-text text :md))))
+  (with-slots (url text) object
+    (setf url (make-pathname :defaults url)
+          text (render-text text :md))))
 
 (defmethod render ((object page) &key next prev)
   ;; For the time being, we'll re-use the normal post theme.

src/content.lisp

@@ -31,16 +31,15 @@
 ;; Content Types
 
 (defclass content ()
-  ((file :initarg :file :reader content-file)
+  ((url  :initarg :url  :reader page-url)
    (date :initarg :date :reader content-date)
-   (path :initarg :path :accessor path-of)
-   (slug :initarg :slug :accessor slug-of)
-   (tags :initarg :tags :accessor content-tags)
-   (text :initarg :text :accessor content-text))
-  (:default-initargs :tags nil :date nil :slug nil))
+   (file :initarg :file :reader content-file)
+   (tags :initarg :tags :reader content-tags)
+   (text :initarg :text :reader content-text))
+  (:default-initargs :tags nil :date nil))
 
 (defmethod initialize-instance :after ((object content) &key)
-  (with-accessors ((tags content-tags)) object
+  (with-slots (tags) object
     (when (stringp tags)
       (setf tags (mapcar #'make-tag (cl-ppcre:split "," tags))))))
 

src/documents.lisp

@@ -26,18 +26,17 @@
 ;; Instance Methods
 
 (defgeneric page-url (document)
-  (:documentation "The url to the DOCUMENT without the domain.")
-  (:method (document)
-    (let* ((class-name (class-name (class-of document)))
-           (route (get-route class-name)))
-      (if route
-          (format nil route (slug-of document))
-          (error "No routing method found for: ~A" class-name)))))
+  (:documentation "The relative URL to the DOCUMENT."))
 
-(defmethod page-url :around ((document t))
-  (let* ((result (call-next-method))
-         (type (or (pathname-type result) (page-ext *config*))))
-    (make-pathname :type type :defaults result)))
+(defun compute-url (document unique-id)
+  "Compute the relative URL for a DOCUMENT based on its UNIQUE-ID."
+  (let* ((class-name (class-name (class-of document)))
+         (route (get-route class-name)))
+    (unless route
+      (error "No routing method found for: ~A" class-name))
+    (let* ((result (format nil route unique-id))
+           (type (or (pathname-type result) (page-ext *config*))))
+      (make-pathname :type type :defaults result))))
 
 (defgeneric render (document &key &allow-other-keys)
   (:documentation "Render the given DOCUMENT to HTML."))

src/feeds.lisp

@@ -3,7 +3,7 @@
 ;;; Atom and RSS Feeds
 
 (defclass feed (index)
-  ((format :initform nil :initarg :format :accessor feed-format)))
+  ((format :initform nil :initarg :format :reader feed-format)))
 
 (defclass standard-feed (feed) ())
 

src/indexes.lisp

@@ -6,13 +6,13 @@
   "The list of tags which content has been tagged with.")
 
 (defclass index ()
-  ((path :initarg :path :accessor path-of)
-   (slug :initarg :slug :reader slug-of)
-   (title :initarg :title :reader title-of)
+  ((url     :initarg :url     :reader page-url)
+   (title   :initarg :title   :reader title-of)
    (content :initarg :content :reader index-content)))
 
-(defmethod initialize-instance :after ((object index) &key)
-  (setf (path-of object) (page-url object)))
+(defmethod initialize-instance :after ((object index) &key slug)
+  (with-slots (url) object
+    (setf url (compute-url object slug))))
 
 (defmethod render ((object index) &key prev next)
   (funcall (theme-fn 'index) (list :tags (find-all 'tag-index)

src/posts.lisp

@@ -1,18 +1,14 @@
 (in-package :coleslaw)
 
 (defclass post (content)
-  ((title :initarg :title :reader title-of)
-   (author :initarg :author :accessor author-of)
-   (format :initarg :format :accessor post-format))
+  ((title  :initarg :title  :reader title-of)
+   (author :initarg :author :reader author-of)
+   (format :initarg :format :reader post-format))
   (:default-initargs :author nil))
 
 (defmethod initialize-instance :after ((object post) &key)
-  (with-accessors ((title title-of)
-                   (author author-of)
-                   (format post-format)
-                   (text content-text)) object
-    (setf (slug-of object) (slugify title)
-          (path-of object) (page-url object)
+  (with-slots (url title author format text) object
+    (setf url (compute-url object (slugify title))
           format (make-keyword (string-upcase format))
           text (render-text text format)
           author (or author (author *config*)))))