editor: generalize `process-content`

This way the same logic can be re-used for saving and loading files

editor.hy

@@ -19,7 +19,7 @@ This application will serve as a platform to edit and deploy posts.
 ;; experimentation in hand-written test posts, and it should be applied to
 ;; all existing posts before being changed here.
 (setv post-template
-  (Template ;"${title}\n${date}\n${summary}\n${content}"))
+  (Template
     "{% if type == \"rss\" %}\n\t{% extends \"rss-item.xml\" %}\n{% else %}\n\t{% extends \"blog-post.html\" %}\n{% endif %}\n\n{% block title %}${title}{% endblock title %}\n{% block date %}${date}{% endblock date %}\n{% block summary %}\n\t${summary}{% endblock summary %}\n{% block content %}\n\t<p>\n\t\t${content}\t</p>\n{% endblock content %}"))
 
 ;; Setup top-level and main Frame
@@ -67,13 +67,28 @@ This application will serve as a platform to edit and deploy posts.
 		:title (.get post-title)
 		:date post-date
 		:summary (.get post-summary "1.0" "end")
-		:content (process-content (.get post-content "1.0" "end"))))))
+		:content (process-content-write (.get post-content "1.0" "end"))))))
+
+;; string string -> string
+;; process raw-input according to mode
+;; if mode is "w", wrap paragraphs in HTML "<p>" tags
+;; if mode is "r", replace HTML "<p>" tags with "\n\n"
+(defn _process-content [raw-input mode]
+  (setv read-chars "\n\n")
+  (setv write-chars "\n\t</p>\n\t<p>\n\t\t")
+  (return (if (= mode "r")
+	      (.replace raw-input write-chars read-chars)
+              (.replace raw-input read-chars write-chars))))
 
 ;; string -> string
-;; split the string into paragraphs, delimited by `\n\n`,
-;; and wrap them in HTML paragraph tags `<p></p>`
-(defn process-content [raw-input]
-  (return (.replace raw-input "\n\n" "\n\t</p>\n\t<p>\n\t\t")))
+;; call `_process-content` with a mode of "w"
+(defn process-content-write [raw-input]
+  (return (_process-content raw-input "w")))
+
+;; string -> string
+;; call `_process-content` with a mode of "r"
+(defn process-content-read [raw-input]
+  (return (_process-content raw-input "r")))
 
 ;; thunk
 ;; save the current contents of the editor then