Add multiline prefixes & AI response prefixes (#142)

gptel: Add customizable prompt/response prefixes

gptel.el (gptel-prompt-prefix-alist, gptel-response-prefix-alist,
gptel-prompt-prefix-string, gptel-response-prefix-string,
gptel--url-get-response): Add customizable response prefixes (per
major-mode) in `gptel-response-prefix-alist`.

Rename `gptel-prompt-string` -> `gptel-prompt-prefix-string`

The function `gptel-response-prefix-string` returns the prefix
string for the response in the current major-mode.

gptel-openai.el, gptel-ollama.el (gptel--parse-buffer): Remove the
prompt and response prefixes when creating prompt strings to send
to the LLM API.

gptel-curl.el (gptel-curl--stream-cleanup,
gptel-curl--stream-insert-response): Insert the response prefix
for the current major-mode before inserting the LLM API response.

gptel-curl.el

@@ -183,7 +183,7 @@ PROCESS and _STATUS are process parameters."
             (with-current-buffer (marker-buffer start-marker)
               (pulse-momentary-highlight-region (+ start-marker 2) tracking-marker)
               (when gptel-mode (save-excursion (goto-char tracking-marker)
-                                               (insert "\n\n" (gptel-prompt-string)))))
+                                               (insert "\n\n" (gptel-prompt-prefix-string)))))
             (with-current-buffer gptel-buffer
               (when gptel-mode (gptel--update-header-line  " Ready" 'success))))
         ;; Or Capture error message
@@ -232,7 +232,10 @@ See `gptel--url-get-response' for details."
               (gptel--update-header-line " Typing..." 'success)
               (goto-char start-marker)
               (unless (or (bobp) (plist-get info :in-place))
-                (insert "\n\n"))
+                (insert "\n\n")
+                (when gptel-mode
+                  ;; Put prefix before AI response.
+                  (insert (gptel-response-prefix-string))))
               (setq tracking-marker (set-marker (make-marker) (point)))
               (set-marker-insertion-type tracking-marker t)
               (plist-put info :tracking-marker tracking-marker))

gptel-ollama.el

@@ -89,9 +89,11 @@ Ollama models.")
                      :system gptel--system-message
                      :prompt
                      (if (prop-match-p prop)
-                         (string-trim (buffer-substring-no-properties (prop-match-beginning prop)
+                         (string-trim
-                                                                      (prop-match-end prop))
+                          (buffer-substring-no-properties (prop-match-beginning prop)
-                                      "[*# \t\n\r]+")
+                                                          (prop-match-end prop))
+                          (format "[\t\r\n ]*%s[\t\r\n ]*" (regexp-quote (gptel-prompt-prefix-string)))
+                          (format "[\t\r\n ]*%s[\t\r\n ]*" (regexp-quote (gptel-response-prefix-string))))
                        ""))))))
 
 ;;;###autoload

gptel-openai.el

@@ -100,7 +100,8 @@
                   (string-trim
                    (buffer-substring-no-properties (prop-match-beginning prop)
                                                    (prop-match-end prop))
-                   "[*# \t\n\r]+"))
+                   (format "[\t\r\n ]*%s[\t\r\n ]*" (regexp-quote (gptel-prompt-prefix-string)))
+                   (format "[\t\r\n ]*%s[\t\r\n ]*" (regexp-quote (gptel-response-prefix-string)))))
             prompts)
       (and max-entries (cl-decf max-entries)))
     (cons (list :role "system"

gptel.el

@@ -230,11 +230,22 @@ defaults to `text-mode'."
     (text-mode . "### "))
   "String inserted after the response from ChatGPT.
 
-This is an alist mapping major modes to the prefix strings. This
+This is an alist mapping major modes to the prefix strings.  This
 is only inserted in dedicated gptel buffers."
   :group 'gptel
   :type '(alist :key-type symbol :value-type string))
 
+(defcustom gptel-response-prefix-alist
+  '((markdown-mode . "")
+    (org-mode . "")
+    (text-mode . ""))
+  "String inserted after the response from ChatGPT.
+
+This is an alist mapping major modes to the reply prefix strings.  This
+is only inserted in dedicated gptel buffers before the AI's response."
+  :group 'gptel
+  :type '(alist :key-type symbol :value-type string))
+
 (defcustom gptel-crowdsourced-prompts-file
   (let ((cache-dir (or (getenv "XDG_CACHE_HOME")
                        (getenv "XDG_DATA_HOME")
@@ -412,9 +423,12 @@ and \"apikey\" as USER."
      (skip-syntax-forward "w.")
      ,@body))
 
-(defun gptel-prompt-string ()
+(defun gptel-prompt-prefix-string ()
   (or (alist-get major-mode gptel-prompt-prefix-alist) ""))
 
+(defun gptel-response-prefix-string ()
+  (or (alist-get major-mode gptel-response-prefix-alist) ""))
+
 (defun gptel--restore-state ()
   "Restore gptel state when turning on `gptel-mode'.
 
@@ -733,11 +747,13 @@ See `gptel--url-get-response' for details."
                 (goto-char start-marker)
                 (run-hooks 'gptel-pre-response-hook)
                 (unless (or (bobp) (plist-get info :in-place))
-                  (insert "\n\n"))
+                  (insert "\n\n")
+                  (when gptel-mode
+                    (insert (gptel-response-prefix-string))))
                 (let ((p (point)))
                   (insert response)
                   (pulse-momentary-highlight-region p (point)))
-                (when gptel-mode (insert "\n\n" (gptel-prompt-string))))
+                (when gptel-mode (insert "\n\n" (gptel-prompt-prefix-string))))
               (when gptel-mode (gptel--update-header-line " Ready" 'success))))
         (gptel--update-header-line
          (format " Response Error: %s" status-str) 'error)
@@ -969,9 +985,9 @@ buffer created or switched to."
       (visual-line-mode 1))
      (t (funcall gptel-default-mode)))
     (unless gptel-mode (gptel-mode 1))
-    (if (bobp) (insert (or initial (gptel-prompt-string))))
     (goto-char (point-max))
     (skip-chars-backward "\t\r\n")
+    (if (bobp) (insert (or initial (gptel-prompt-prefix-string))))
     (when (called-interactively-p 'gptel)
       (pop-to-buffer (current-buffer))
       (message "Send your query with %s!"