Move CONSTRUCT into util, it's more general than CONTENT.

src/config.lisp

     (let ((config-form (read in)))
       (if (symbolp (car config-form))
           ;; Single site config: ignore CONFIG-KEY.
-          (setf *config* (apply #'make-instance 'blog config-form))
+          (setf *config* (construct 'blog config-form))
           ;; Multi-site config: load config section for CONFIG-KEY.
           (let* ((config-key-pathname (cl-fad:pathname-as-directory config-key))
                  (section (assoc config-key-pathname config-form
                                  :key #'cl-fad:pathname-as-directory
                                  :test #'equal)))
             (if section
-                (setf *config* (apply #'make-instance 'blog (cdr section))
+                (setf *config* (construct 'blog (cdr section))
                       (repo *config*) config-key)
                 (error 'unknown-config-section-error
                        :text (format nil "In ~A: No such key: '~A'." in config-key)))))

src/content.lisp

    (date :initform nil :initarg :date :accessor content-date)
    (text :initform nil :initarg :text :accessor content-text)))
 
-(defun construct (content-type args)
-  "Create an instance of CONTENT-TYPE with the given ARGS."
-  (apply 'make-instance content-type args))
-
 (defun tag-p (tag obj)
   "Test if OBJ is tagged with TAG."
   (member tag (content-tags obj) :test #'tag-slug=))

src/util.lisp

 (in-package :coleslaw)
 
+(defun construct (class-name args)
+  "Create an instance of CLASS-NAME with the given ARGS."
+  (apply 'make-instance class-name args))
+
 (defun fmt (fmt-str args)
   "A convenient FORMAT interface for string building."
   (apply 'format nil fmt-str args))