Allow arbitrary tag names. However if two tags have the same slug they will be merged.

The name of the merged tag will be one of the original names.
However this should not happen in practice.

coleslaw.asd

@@ -19,6 +19,7 @@
                (:file "util")
                (:file "config")
                (:file "themes")
+               (:file "tags")
                (:file "content")
                (:file "posts")
                (:file "indices")

src/content.lisp

@@ -30,9 +30,11 @@
            (nth-value 1 (cl-ppcre:scan-to-strings "[a-zA-Z]+: (.*)" str)))
          (field-name (line)
            (make-keyword (string-upcase (subseq line 0 (position #\: line)))))
-         (read-delimited (str &optional (delimiter ", "))
-           (mapcar (compose #'slugify #'string-downcase)
-                   (cl-ppcre:split delimiter str))))
+         (read-tags (str)
+           (mapcar (lambda (name) 
+		     (let ((name (string-trim " " name)))
+		       (make-instance 'tag :name name :slug (slugify name))))
+                   (cl-ppcre:split "," str))))
     (with-open-file (in file)
       (unless (string= (read-line in) ";;;;;")
         (error "The provided file lacks the expected header."))
@@ -41,7 +43,7 @@
                      appending (list (field-name line)
                                      (aref (parse-field line) 0))))
             (content (slurp-remainder in)))
-        (setf (getf meta :tags) (read-delimited (getf meta :tags)))
+        (setf (getf meta :tags) (read-tags (getf meta :tags)))
         (append meta (list :text content))))))
 
 (defun find-all (content-type)

src/feeds.lisp

@@ -17,7 +17,7 @@
       (write-page (page-path rss) (render-page rss rss-template))
       (write-page (page-path atom) (render-page atom atom-template))
       (dolist (feed feeds)
-        (let ((index (index-by-tag feed by-date)))
+        (let ((index (index-by-tag-name feed by-date)))
           (setf (index-id index) (format nil "~a-rss.xml" feed)
                 (index-posts index) (first-10 (index-posts index)))
           (write-page (page-path index) (render-page index rss-template)))))))

src/indices.lisp

@@ -35,7 +35,7 @@
 (defun all-tags ()
   "Retrieve a list of all tags used in content."
   (let ((tags (mappend #'content-tags (hash-table-values *content*))))
-    (sort (remove-duplicates tags :test #'string=) #'string<)))
+    (sort (remove-duplicates tags :test #'tag-slug=) #'string< :key #'tag-name)))
 
 (defun get-month (timestamp)
   "Extract the YYYY-MM portion of TIMESTAMP."
@@ -43,10 +43,18 @@
 
 (defun index-by-tag (tag content)
   "Return an index of all CONTENT matching the given TAG."
-  (flet ((valid-p (obj) (member tag (content-tags obj) :test #'string=)))
-    (make-instance 'tag-index :id tag
+  (flet ((valid-p (obj) (member tag (content-tags obj) :test #'tag-slug=)))
+    (make-instance 'tag-index :id (tag-slug tag)
                               :posts (remove-if-not #'valid-p content)
-                              :title (format nil "Posts tagged ~a" tag))))
+                              :title (format nil "Posts tagged ~a" (tag-name tag)))))
+
+(defun index-by-tag-name (name content)
+  "Return an index of all CONTENT matching the given tag with tag NAME.
+The comparison is done by comparing the slugs because that is what 
+uniquely identifes a tag."
+  (index-by-tag 
+   (find (slugify name) (all-tags) :test #'string= :key #'tag-slug)
+   content))
 
 (defun index-by-month (month content)
   "Return an index of all CONTENT matching the given MONTH."

src/tags.lisp

@@ -0,0 +1,12 @@
+(in-package :coleslaw)
+
+(defclass tag ()
+  ((name :initform nil :initarg :name :accessor tag-name)
+   (slug :initform nil :Initarg :slug :accessor tag-slug)))
+
+(defun tag-name= (tag-1 tag-2)
+  (string= (tag-name tag-1) (tag-name tag-2)))
+
+(defun tag-slug= (tag-1 tag-2)
+  (string= (tag-slug tag-1) (tag-slug tag-2)))
+

themes/hyde/index.tmpl

@@ -17,7 +17,7 @@
 <div id="tagsoup">
   <p>This blog covers
     {foreach $tag in $tags}
-      <a href="{$config.domain}/tag/{$tag}.html">{$tag}</a>{nil}
+      <a href="{$config.domain}/tag/{$tag.slug}.html">{$tag.name}</a>{nil}
       {if not isLast($tag)},{sp}{/if}
     {/foreach}
 </div>

themes/hyde/post.tmpl

@@ -5,7 +5,7 @@
   <h1 class="title">{$post.title}</h1>{\n}
   <div class="tags">{\n}
     Tagged as {foreach $tag in $post.tags}
-                <a href="../tag/{$tag}.html">{$tag}</a>{nil}
+                <a href="../tag/{$tag.slug}.html">{$tag.name}</a>{nil}
                     {if not isLast($tag)},{sp}{/if}
               {/foreach}
   </div>{\n}